# Dave's twin



## Dave G (Dec 8, 2011)

Well, I have finally found some time to start another engine. This will be my first attempt at posting a build here so please keep this in mind as we go. Any helpful suggestions on my posting will be gratefully accepted.

I like to build my own designs and I have been thinking about this one for a while now. It will be a twin cylinder IC engine of four stroke design. I have wanted to build an engine with all roller bearing construction for a while now and this is what I have come up with. I don't normally do much drawing before I start and this one will be no different. I hope you will be able to follow along and as it takes shape it should become much clearer to understand. 

I picked up a couple of 2:1 bevel gear sets at an engine show a while back and tried to figure how I could incorporate them into an engine. What I came up with is the smaller gears which are the pinions are on integral shafts which will have crankdisks attached to the outboard ends. The pinions will act on the larger ring gear which the flywheel will be attached to.
So the flywheel will rotate at half engine speed with the exhaust valve cam attached to the other end of this shaft. One cam lobe will operate both cylinders. This will be a slow speed throttle governed engine so I will use atmospheric intake valves. The first pic I have is of the work I have finished so far( not much ). 







Here I have one pinion assembly put together and the other in pieces. These are constructed like the pinion supports in Ford 9" differentials.


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## Dave G (Dec 8, 2011)

The crankdisks were made from a piece of 2 3/4 hex 12L14 I had laying around. This pic shows the turning done and then setup in the mill vise and the 3/8-24 tapped hole for the rod journal already done.






The pinion shafts were .500 dia when started but I had to install a sleave on the shafts to get the right dias. for the taper roller bearings to fit. While I had to OD grind the sleave to dia I went ahead and ground the crankdisk dia to .497. to true it up with my new dias. The crankdisks were bored on the lathe to .496" dia to be honed to size later. The small dia is for a .875" dia seal to ride on.


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## Dave G (Dec 8, 2011)

Here I have used a 1/2" dia endmill to make the cuts for the sides of the crankdisk.






These cuts were made referenced from the center of the part and the depth was greater then needed for a reason I will explain later. The cuts were terminated just short of contacting the seal dia.


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## Dave G (Dec 8, 2011)

This pic shows the part rotated in the vise and clamped on the flats of the hex as before. Now a cut was made to form one of the sides of the counterweight.


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## Dave G (Dec 8, 2011)

Here I have once again rotated the part in the vise jaws and made the cut for the other side of the counterweight.


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## Dave G (Dec 8, 2011)

Now I have repositioned the part in the vise so I can radius the rod journal end of the crankdisk. I did this with a 3/8" corner round cutter.






After completing the radii I took the part to the cutoff saw and severed the part from the stock.


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## Dave G (Dec 8, 2011)

Now I need to finish the crankdisk to width. I clamped the disk in the lathe using a 7/8" collet. Taking light cuts I faced the disk so it was cleaned up but not to size. I need to have both faces parallel to each other so after cleaning up the surface I measured the width with mics to check for parallelism. I found the disk to be out of kilter about .002". I marked the thickest point on the face with a marker and then put my dial indicator on the face of the disk and where it was the thickest I lightly tapped the part until my indicator gave me a reading of about .003" runout. Another light cut was made and then checked again with my mics. I did this until I had less than .0005" difference in thickness and then I faced the part to a thickness of .375".






Once both crankdisks were finished to thickness they were deburred and then I honed the bores to .497 plus about .0003 for clearance for the shafts.


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## kuhncw (Dec 8, 2011)

Hello Dave,

This looks like an interesting and informative build. I'll looking forward to following your notes and photos.

What bore and stroke are you planning?

Regards,

Chuck


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## metalmad (Dec 9, 2011)

Hi Dave 
Ive been waiting for this build for ages.
Looking great so far :bow: :bow:
Pete


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## Dave G (Dec 9, 2011)

Thanks guys, This thing will have a 1.250" bore and a 2" stroke. I have some rings left from my sideshaft engine build which also has a 1.250" bore. I am going to try to duplicate the rod length and stroke combination from my sideshaft to help cut down on the engineering abit. The compression ratio will be 4:1, I have tendency to build too much compression in my engines so this one will be kept low. I use a Sunnen honing machine to finish my cylinders and one ring on the piston and usually get good compression this way. 

 My biggest concern with this engine is starting it. Because the flywheel runs at half speed and the engine will be started from the flywheel shaft, the mechanical disadvantage of the flywheel turning the crankdisks will make it difficult to turn. I hoping the low compression and maybe a handcrank of large proportion will do the trick, we will see. I may have to borrow one of those starters the top fuel dragster guys use. 


Keep tuned and lets hope all goes well, Dave


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## kuhncw (Dec 9, 2011)

How about commpression release/priming petcocks like the old two cylinder John Deeres with no electric start.

As a kid, I enjoyed watching our neighbor grab the flywheel and crank his 1937 G. Sixty two years later I can still hear all the hissing as the cylinders came up on compression and began to fire. Odd the things we remember for years.

Regards,


Chuck


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## Dave G (Dec 9, 2011)

Heres a pic of grinding the OD of the pinion shaft.







I had 2 bearing dias and the crankdisk dia to grind.


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## Dave G (Dec 9, 2011)

This may help clear up what I'm trying build. 






The flywheel is a weight that came off the slip yoke of a Dodge truck transmission. I chucked it up in the lathe and turned all the surfaces true to clean them up. I finished the pinion support assemblies today. I had to surface grind the thickness of the inner spacer of the second assembly to get the proper preload on the bearings. I also broached the keyways in the crankdisks for the woodruff keys in the pinion shafts. This took some doing as the keyways have to be indexed with the rod pin holes. A keyway broach bushing and an alignment fixture to orient it. It took all day to make the fixtures and about 2 minutes to broach the keyway. 
 I like the idea of a compression release Chuck, I will make sure I leave enough room in the head for one if needed. Thank you!

 Next will be the shaft for the ring gear and then the bearing supports for this shaft. Once I have the these bearing supports finished I can determine the width and length of the gearcase. The gearcase will be a weldment made from 1018 CRS with a permanent floor and a removable lid. It looks like it will be roughly 3.25" square and about 2.5" tall.


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## Dave G (Dec 9, 2011)

Hey Chuck, a former coworker of mine was heavy into JD tractors and he told me his father once had a H that they could start by rolling the flywheel over with their foot as they were sitting in the seat. He said that they would run that way if you knew how to tune one. I have always liked the sound of them running under load. Maybe an idea for a future project. Dave


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## stevehuckss396 (Dec 9, 2011)

Dave G  said:
			
		

> Well, I have finally found some time to start another engine. This will be my first attempt at posting a build here so please keep this in mind as we go. Any helpful suggestions on my posting will be gratefully accepted.



I have been in your shoes Dave. Don't let it bother you too much. Show everything warts and all. It's important to show that no matter who you are, there are struggles along the way. Show the victorys and also show the parts where you need to step back, change your plan, and push on to the finish. I think it's important because it makes all of us feel like we are not the only ones who make a boo boo here and there. I think you will find overwelming support, I did!

BTW Don't forget to have fun!!

Steve


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## Dave G (Dec 9, 2011)

Thanks Steve, I think I have just about everything figured out but we all know that goes. I find I get more enjoyment out of completing a project and sharing it with everyone who has an interest in it than the actual building of the engine. Maybe too many years of making parts for a living has me a little burned out at times. My motivation for building these things is to have something new to take to shows to share with all who care and to leave something for my kids and grandson to have that is different than the normal things we hand down. 
 Oh, and by the way, there will be warts. I normally don't get to concerned with a part if it has, shall we say, an unplanned feature that gives it character, as long as it functions I will usually use it and maybe go back and clean it up or replace it after I'm sure the design is workable. 
 I will try to post the making of as many parts as I can. I don't have any CNC capability in my shop so all the components will be made on conventional equiptment. Hopefully my methods will help others and that is why I will post them. Once again, Thank You, Dave


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## Dave G (Dec 12, 2011)

Had a little time today to make the flywheel shaft. This pic is of turning the first end of the shaft. First I faced the ends to length and then drilled and tapped a 10-32 hole in each end. I used a #3 center drill to leave a center in each end for OD grinding. After finishing the ends I turned one end to size leaving .010" on the ODs for grinding stock.








This pic shows the shaft reversed in the chuck and the second end being turned to size. Also you can see the undercut for the thread that will be for the bearing nut. These dias have .010" grind stock on them also.






Now we go to the OD grinder to finish the ODs to size. One dia is for the bearings and this gets a light slip fit. Another dia is for the gear and this is a light slip fit also. I ground the dia for the flywheel hub to .6250". On the flywheel end there is a .500" dia for a pulley or starter fixture. The small end is for a hardened sleeve for a needle roller bearing and for the timing wheel.


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## Dave G (Dec 12, 2011)

Here we have the shaft with the gear and the bearings installed.






Now I needed to single point the threads for the bearing nuts. These threads are .586-32 for a N-02 nut. This info is taken from my Machinery Handbook.


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## Dave G (Dec 12, 2011)

Heres the shaft with the threading finished.






A pic of the shaft with the nuts in place.






One nut will hold the flywheel hub to the shaft and retain the bearings. The other will hold the gear and the cam ring to the shaft. All the diameters have to be concentric with each other and that is why I choose to grind them. Grinding between centers allows me to flip the part end for end and still have concentricity. Also on the critical dias like for the bearings and the gear I used a snap gage that has a .0001" resolution and are set with gage blocks. Getting the taper out of the part when grinding is done by adjusting the table of the grinder. I set a .0005" indicator on the end of the table and use this for a reference. The bearing dia has less than .0001" taper on it for the length of 1.570".


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## Dave G (Dec 12, 2011)

This pic shows the keyway being cut for the locking tab washer for the locknut. This info is also taken from the Machinery Handbook. These bearing locknuts are made in different sizes to mate with the different bearing bores avaliable. The locknuts have a locking tab washer that goes between the nut and the bearing and once the nut is tightened to the desired torque one of the locking tabs must be folded over the nut to keep it from loosening during operation. 






Next I will need to cut a couple of woodruff keyways in the shaft. One is for the gear and the other is for the flywheel hub.
Once these keyways are cut the shaft will be finished. The next part will be the bearing retainer for the outer races.


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## Dave G (Dec 14, 2011)

Heres a pic of cutting the Woodruff keyway. The shaft is held in the vise jaws using V-blocks. I used my angle plate on the outboard end for support. The center in "Z" was found by using a piece of .004" thick paper between the cutter and the major dia of the part. The knee was raised until the paper walks out from between cutter and the part and then Zero was set. I next moved the knee up in .001" increments until it lightly touched the part. This was done with the cutter rotating and I reset my Zero. Now I moved the knee up half the dia of my shaft and half the thickness of the cutter to put me on center. 







The info for the depth of cut was taken from my Machinery Handbook.


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## Dave G (Dec 14, 2011)

I had to grind .001" off the thickness of the Woodruff key to get it to fit the keyway. I always block the part to be ground with parallels to keep it from flying off the table when grinding.


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## coopertje (Dec 15, 2011)

Hi Dave, looking great so far! Love your finishing, I never get my parts looking so shiny and without machine marks..... :bow:

Seems that you have some nice (and serious) equipment in your shop, if possible could you post some pictures of the grinding machine you build? I have a clarcson tool grinder and I am thinking to make some additions to that machine so I can use it as a grinding machine too. 

Have fun, regards Jeroen


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## Dave G (Dec 15, 2011)

Hi Jeroen, Thanks for the support. My OD grinder is a Myford that I bought used at a used machinery dealer. It didn't have a headstock or a tailstock so I had to make them. The headstock has 2 angular contact bearings on the outboard end and a precision ball bearing on the inboard end. The shaft that the bearings ride on has a tapered hole in one end for a dead center and is bolted to the support on the other. When making the supports for the shaft I tried to keep everything as square as I could get it. The housing for the outer races of the bearings was probably the hardest part to make. The outer race bores had to be very concentric so I ground them on a bore grinder using shoes. When grinding between centers the housing is used just as a driver for the workpiece but I can also bolt a 5" dia magnetic chuck to it for other applications. 

The tailstock is just a spring loaded spindle with a tapered hole in it for a dead center. There is an adjustment for the spring tension on the center. 

The headstock is powered by a DC variable speed motor connected with a v-belt. 

When OD grinding I will normally use a snap gage to check for size and to be able to correct for taper in the part. On the shaft I just made I held the dias to within .0001" in size and taper for the length of the surface. I grind all my crankshaft journals and any dia I want to hold close.


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## Dave G (Dec 15, 2011)

This is a pic of the bearing housing for the flywheel shaft. Here I have turned all the dias leaving stock for finishing. I don't normally finish any dias until the part is roughed to size and I leave .02 to .03 on each dia. 






Here I have just finished the bore for the outer race of the bearing on the outboard side of the housing. This boring bar was made from a piece of 4140 and the tool is a broken center drill.






After finishing the face and all the dias to size the part was reversed in the chuck and lightly clamped. A light cut was taken on the face and then checked with mics to see if the part was sitting in the jaws square. The part was tapped until it ran true and then faced to length. My 3 jaw chuck is of the adjustable type so I indicated the bore until I got it running within .0002" TIR. Next I bored the other outer race dia and deburred the part.


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## Dave G (Dec 15, 2011)

From here I needed to drill some mounting holes in the part. I placed a support piece under the part to give me table clearance and bolted the part through the center to the table of the mill. In this pic I am indicating the OD of the part to find center.






The support will be bolted to the gear housing using 8 10-32 capscrews. The holes for these fall on the intersection of 2 surfaces on the face of the part so I needed to spotface the locations of the holes first with an endmill.








After spotfacing I center drilled and then drilled the clearance holes for the fasteners.


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## Dave G (Dec 15, 2011)

Here we have the counterbores finished. 






Now I needed to cut a couple of grooves in the part for a punch just in case I ever have to replace the outer races of the bearings. I had to reclamp the part from the outside so I could access the bore.






The face of the housing got 8 4-40 tapped holes in it for a seal retainer.


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## coopertje (Dec 16, 2011)

Hi Dave,

Thanks for the picture of the tool grinder! You did a very nice job on completing the missing parts, must have been fun to do. I truly like these kind of machines, they are very robust and evenbetter most of the times affordable. I do not have space for more machines so I have to stick with what I have. It seems that the only thing missing to convert my Clarcson mill grinder into an OD and surface grinding machine are 2 centers and a variable speed motor. That's not too bad I guess. I would really appreciate to see a detail on your spring tension adjustment, hope I am not nagging now :'(

Regards Jeroen


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## Dave G (Dec 17, 2011)

Jeroen, Heres a pic of the spring I used for tension on the center. On the table is the adjuster nut.






Heres a pic of the lever for retracting the center to install the part on the centers. On the back side of the mounting block that the lever shaft goes through is another lever that goes up into a groove in the tailstock spindle. Move the handle to the right and the center retracts.


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## Dave G (Dec 17, 2011)

Back to the twin. Heres a pic of the 3 gearshafts with the bearing housings installed. They are placed where they should be. I have to make the spacer for the flywheel bearings yet and grind it to length to get the proper endplay. I also need to make a wrench for the bearing nuts. After that will be the gear housing which will be a weldment.


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## metalmad (Dec 17, 2011)

Hi Dave
The quality of your work is amazing, really something to aspire to
 :bow: :bow:
Pete


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## coopertje (Dec 18, 2011)

Perfect pictures and explanation Dave, thank you so much! If you don't mind I will "steel" this idea to transform my toolgrinder in a OD grinding machine. 
Your engine project is going very well, looks good! Keep the progress coming, its a pleasure to follow your building steps!

Regards Jeroen


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## Dave G (Dec 18, 2011)

Thank you Pete, Your support is a big help in keeping me going on this project. 

Jeroen, I am happy to help and steal all you want. Thanks for the support on my engine, building these things is always a challenge and its good when others take an interest. If anyone can benefit from the postings then that makes it all worthwhile. 

I have a couple Christmas presents to make this week so the postings will probably be a little light until they're finished. One is for my new grandson and another for a good friend. I like to wait until the last minute, actually I don't like to wait until the last minute, it just happens that way. I have to make a stable for the Baby Jesus in my grandson's Nativity scene. I just hope he doesn't grow up thinking his grandpa made the stable that Jesus was born in. Dave


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## Dave G (Dec 27, 2011)

Lets get back at it. I have made the spacer for the flywheel bearings and have adjusted the endplay by grinding this spacer to the proper thickness. I have also made a wrench to tighten the bearing nuts. This pic shows the parts needed for the weldment of the gearcase.






This pic shows the parts clamped and ready to be welded. A generous chamfer was machined on all the joints to help with penetration. I will bewelding with my Lincoln 175 amp Tig welder.






And now we have a welded up block of steel.


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## Dave G (Dec 27, 2011)

I took the liberty of removing some of the weld that was sticking up off the part by milling. 






After welding and some mill cleanup the gearcase was deburred and placed on the surface grinder to clean up the top and bottom surfaces. This gave me 2 parallel surfaces to locate the other surfaces from.


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## Dave G (Dec 27, 2011)

The gearcase is clamped to my angle plate to grind the 3rd surface. By clamping the bottom surface to the angle plate which is known to be square, we will now have the 3rd side square to the reference side which is the bottom. 






After grinding the 3rd side to cleanup it is unclamped and this side is placed down on the chuck and the 4th side is ground to clean up. Now we should have 4 sides ground and square and parallel to each other.

To grind the 5th side we will need to lay the angle plate on its side on the magnetic chuck of the grinder. I will place the bottom face of the gearcase up against the angle plate and the 3rd face I ground down on the chuck. The magnet is energized and then the part is clamped to the angle plate.


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## Dave G (Dec 27, 2011)

Once the gearcase is clamped to the angle plate the chuck is released and the assembly is rotated on the chuck to allow the 5th side to be ground.






Once the 5th side is cleaned up the gearcase can be unclamped from the angle plate and then placed on the chuck with the 5th side down to be able to grind the 6th side.


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## Dave G (Dec 27, 2011)

Now we should check to see how square our gearcase really is. I didn't grind any surfaces to dimension yet because I want to see how square the surfaces are to each other. It may need correction so it is best to check before sizing. For this I needed my granite surface plate, a .0001 indicator and base, a cylindrical square, and a gage ball stop. 






The indicator is placed above the ball stop and centered with it by eyeball as best that one can. The cylindrical square is pushed up to touch the ball stop and the indicator is adjusted to read zero when touching the square.






To check to see if the indicator stylus is in the center of the gageball the cylindrical square can be rotated side to side while still touching the gageball. The indicator needle should drop off the same amount on each side when rotated. Whats really neat about using a cylindrical square is you can now check the cylindrical square in many places by rotating the square. Any inaccuracies can be compensated by averaging. 


This pic shows the gearcase being checked for squareness.






I found that the worst side was out by less than .0003". Most of the sides were within .00015" and I can live with that. Next I will make a cover for the gearcase and attach it and then I will grind the gearcase to the proper dimensions.


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## stevehuckss396 (Dec 27, 2011)

I could live with .00015 also but I never get the chance to live with it.

I have a cylindrical square but never knew how to use it. 

Looking good Dave!!


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## Dave G (Dec 27, 2011)

Thanks Steve. I spent 6 months in the metrology dept as an apprentice. We were well schooled in how to check things. When we had the opportunity to make an angle plate, as the one you saw in the pics, we would check the squareness as shown. Our goal was less than a .0001" per surface. The trick was to find a journeyman with an angle plate that was good enough to grind from. 

This pic is of the top cover of the gearcase. Here I am spotting the holes with a spotting drill.






Now we drillthe holes. These holes are clearance for an 8-32 flat head.






And now for the countersink.


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## Dave G (Dec 27, 2011)

The gearcase needs 8 8-32 tapped holes put in the top surface for the top cover. This pic is of the gearcase set in the mill vise and using an edgefinder to find the left edge of the part.







Spotting the holes with a spotting drill first.






Then drilling with a tap drill.







Then tapping.


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## Dave G (Dec 27, 2011)

We now have the top cover to the point where we can bolt it to the gearcase so we can surface grind the 4 sides of the gearcase to size. Once this was done the gearcase needed the corners radiused. For this I used a 3/16" corner rounding cutter.






Here we have the gearcase finished ground to size with the top cover installed. 






Tomorrow I hope to be able to bore the holes for the bearing retainers. Once I have the holes bored and the mounting holes tapped I will be able to assemble this thing to see if the gears mesh well.


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## metalmad (Dec 27, 2011)

Hi Dave
Ill be following along for sure Buddy ;D
Pete


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## Dave G (Dec 27, 2011)

Hi Pete, I'm glad you're still with me. I hope this thing will start to look like an engine soon. I know this project is like walking into a room with the lights out for you guys but I hope when the light comes on you will enjoy the effort. Dave


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## smfr (Dec 27, 2011)

Lots of techniques here that are new to me, and I'll take every metrology tip that you can give ;D

Thanks for the clear pictures and detailed explanation.

Simon


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## steamer (Dec 27, 2011)

Looks great from here Dave!

Dave


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## kuhncw (Dec 27, 2011)

Hi Dave,

This is an interesting build and you are doing a fine job on the photos and explanations. Lots to learn in this thread. It appears you are using some sort of coolant or cutting fluid in the shot of the corner radiusing operation. What are you using?

Regards,

Chuck


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## Dave G (Dec 28, 2011)

Hi Chuck, thanks for the support. I am using Tapmagic on the corner round cutter. I have found that climb milling the corner cutter will give you a better finish. I will conventional mill all the stock off except for the last .005" in each axis and then climb mill the finish cut. Bear in mind that I use a Bridgeport copy that has very little backlash. I'm not sure how much luck one would have climb milling on a loose machine so be careful. 
 I am glad you are enjoying the build and I hope something useful can be gotten from the effort. My goal is to have this thing finished for Names 2012 so I will have something new to display. Dave


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## Dave G (Dec 30, 2011)

I had a little time today to do some boring. The first thing I did was to check the tram of my mill. Using my .0005" indicator in my indacol I swept the table anf found it was out .002" side to side. This was corrected and rechecked.






Next I installed the vise on the mill and clamped the gearcase in the vise. Then I indicated the bottom surface and adjusted it until it was true.






I then swept the surface that will be bored to make sure it was in the vise square.









The hole for the flywheel bearing support needs to be in the center of the part in X so an indicator was used to sweep both sides and adjusted until the indicator reads zero on both surfaces.


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## Dave G (Dec 30, 2011)

The hole now needs to be located from the top surface of the gearcase. For this I used my precision edge finder and my .0005" indicator. I could have used a standard edge finder but I thought the forum would like to see another option so I used the edge finder that we used to use to locate holes on a jig grinder. We used to jig grind alot of our tooling as the hole locations had to be held within .0002" - .0005" and the hole sizes also were just as close.






Using a spotting drill to start our hole on location.






Drilling a pilot hole.


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## Dave G (Dec 30, 2011)

Using Silver & Deming drills to open the hole up to 1".






The largest endmill I have is 1.375" dia so it was used to open the hole up even more by plunging.






The finished hole size is 2.000" for the flywheel bearing support so I needed to bore the hole to size from here. Using a HS steel toolbit in my boring head I bored the hole in .10" increments until I was within .030" of final size.


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## Dave G (Dec 30, 2011)

Before finishing the hole to size I removed the boring head from the spindle and replaced it with my drill chuck and used my indicator to check to make sure the part hadn't moved. Once this was confirmed, I finished boring the hole to size. Then the boring bar was used to chamfer the hole.






After the hole was finished to size on the top surface I needed to bore a .8125" dia hole in the opposing surface in the same setup. This was done the same way as before.


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## coopertje (Dec 30, 2011)

Nice work Dave! Very educational and useful information.
Keep the progress coming, I like it a lot. 

Regards Jeroen


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## Dave G (Dec 31, 2011)

Heres a pic of the gearcase with the first hole in it. In this setup I bored the 2.00" hole for the bearing support, tapped 8 10-32 holes for mounting, and bored a .8125" dia hole for a needle roller bearing in the opposing surface. After taking the part from the vise I checked the location of the hole on my surface plate by indicating the low spot of the hole and then flpping the part 180 and rechecking. I was pleasantly surprised by how close to center it was.


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## Brian Rupnow (Dec 31, 2011)

I am absolutely mind boggled that you build an engine without any plan, making it up as you go along. it must work, for I know others do it as well, but I couldn't do that in a thousand years. I'm okay with simple parts that don't interact a great deal with other components, but something as complex as an engine-----no way.----Brian


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## steamer (Dec 31, 2011)

I'm in the same boat Brian....I've tried it too many times and failed miserably ....every time!

Dave


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## Dave G (Dec 31, 2011)

This thing isn't running yet. I was leary of posting this build, it took a long time to convince myself to do it but I figured even if it were a failure, something could be gotten from posting the effort other than a black eye. I've done it before but I will admit this one is a little bit out there. Challenges keep me thinking and out in the shop away from the TV. 

I finished boring the holes for the bearing supports in the gearcase today and after clean up it was assembled to see how my gear mesh was. Looks as though I will need to make a small adjustment in the gear depths but this I will do after finishing the internals of the gearcase. Heres a pic of the gearcase with the bearing supports in place.


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## Dave G (Dec 31, 2011)

A pic of the cover in place.






At the left end of the gearcase in this pic is the end of the flywheel shaft which will have a wheel with a magnet for the spark timing trigger. I will also use this for driving a water pump as it will be liquid cooled. This same end will get busy as there will need to be 2 holes bored for the roller lifters and the mounting holes for the cylinders attachment. If you haven't noticed yet, the crank disks will be rotating in opposite directions from each other. I think the next part I will make is the cam disk. This will be done on the mill using the rotary table. Since this engine has a bore of 1.250" I will make the cam with a valve opening of .125".


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## metalmad (Jan 1, 2012)

This is looking real interesting Mate
Two singles sharing a single flywheel, ignition and god knows what else :big:
This guys is how its done 
The mind Boggles :bow: :bow:
Pete


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## stevehuckss396 (Jan 1, 2012)

I don't even know what it's going to look like and I already want one.


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## gbritnell (Jan 1, 2012)

I'm with Steve. I'm not quite sure how this is going to form up as an engine but the work is first rate. This one definitely has my interest.
gbritnell


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## Dave G (Jan 1, 2012)

I was hoping once I got the gearcase assembled the design would start to take shape. I have some internal parts to make and then we'll start to attach a couple of cylinders to this thing. I find that I like to build things in subassemblies. I will design and build an assembly such as the bearing supports before moving to next part of the build. Building in subassemblies allows me to make changes easily and makes the assembly of the engine less complicated. If I think I'm having trouble with a certain area of the engine it can be removed without much difficulty to be corrected or replaced. Also if an idea for a feature of the engine just doesn't work, not all is lost. I can step back and go a different direction without starting completely over.

I'm glad you guys are following along, I just hope its not like when as a kid I tried unsuccessfully to jump a ditch with my bicycle with all the neighbor kids watching. At least if I fail this time a trip to the ER won't be needed. Evel Kneivel's place in history was never threatened by me and its probably good that I decided to follow a different career path. Dave


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## Dave G (Jan 2, 2012)

Made the cam ring yesterday. Started with a piece of 4140 that was preheattreated to rockwell 32 C. This pic shows the OD being cleaned up. 







Once cleaned up the material was reversed in the chuck jaws and the OD was turned to size and faced. I like to take a cleanup cut on the rough stock so I have a nice true dia to indicate on if needed. 






The bore needs to finish at .625". I bored this to .624" dia leaving .001" for sizing on the sunnen honer. If I want a bore to be concentric with an OD I will always bore and not ream if possible.







Here we have the cam ring turned to size with a counterbore for the retainer nut and backcut for clearance.


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## Dave G (Jan 2, 2012)

After parting off the cam ring from the stock in the lathe I sat the ring on the surface grinder and ground the thickness to size. Now my faces should be parallel to each other.






I needed to make an arbor to mount the cam ring to for milling the cam surface.






Here we have the rotary table mounted on the mill and the arbor clamped in the jaws. An indicator was used to find the center of the arbor in "Y" by sweeping over both sufaces.


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## Dave G (Jan 2, 2012)

The first stock to be removed is the 240 degrees of cam surface that is flat. This was done by touching the endmill to the part and setting zero in "X" and advancing into the part .04". Then the rotary table was rotated 240 degrees cutting away the material. Because I want .125" of lift on the cam numerous cuts had to be taken until I got to full depth.






It may be a little difficult to see in the next pic but the flat surface of the cam is now finished.


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## Dave G (Jan 2, 2012)

Because this is to be an engine that runs at a slow speed I decided to use 240 degrees of duration on the cam. As the cam rotates at half crankshaft speed the cam will only need 120 degrees of duration on it. I have cut 240 degrees of material away already so now I need to cut the ramps for opening and closing of the valve. I left a flat of 10 degrees at the center of the lobe to allow me some room to blend a radius at the full open part of the lobe. That means I will have to open and close the valve in 110 degrees. Divide 110 by 2 and we get 55 degrees per ramp. 

Because I want .125" of lift I will need to divide .125" by 55 to give me .0022" per degree of rotation. If I rotate the rotary table in 2 degree increments I will be able to move the table .0045" in "X" for each cut. Being that my DRO is graduated in .0005 increments this will work out well. Basically what I am doing is positioning the rotary table and "X" axis and then plunging the endmill with my power feed. All this time the "Y" axis stays at zero. Many plunge cuts later I have a ramp with some small facets to be smoothed out later.


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## Dave G (Jan 2, 2012)

This is what spread sheets looked like before computers.






A pic of the finished cam and the fixture for milling. This is after spending about 1 1/2 hours stoning then sanding the cam surface. I started with a hard Arkansas stone using lots of oil and then once the facets disappeared I went to wet/dry sandpaper in 320, 400, then finished with 600 wrapped around a flat bar of steel. 






And a pic of the cam ring in place on it's shaft in the gearcase.






I used a .875" dia endmill to make the cuts on the cam surface. The radius where the flat portion of the cam meets the ramps is .4375" ( half the cutter ). I will use a roller follower with a dia of .500" so I should have a slight easing of the roller opening with the difference of radii. The proper cam shape should be 3 radii all blending with each other but I think the flat flanks on this cam should work alright. The cam and roller followers will be well lubed by gearlube splash.


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## Dave G (Jan 7, 2012)

I made the lifter guides last night. 2 pieces of 1.5" dia 660 bronze were cut off and then the first end was turned smooth until both cleaned up at the same dia. The parts were reversed in the lathe and a 1.400" dia was turned to size up to the chuck jaws. The hole for the in the gearcase will be .5625" so I will need to turn the a .562" dia stopping at .530" from the face of the part. The lifter will be .375" dia so a hole will need to be reamed in the part next. This is a pic of the part up till this point.






Here I have taken the parts to the mill and clamped in the rotary table. I need a .094" wide slot in the center of the part for the roller to be used as a guide to keep the roller straight. First I needed to touch the top of the part with the slitting saw to give me my "Z" zero.


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## Dave G (Jan 7, 2012)

To get the depth in "Z" we will need to add the width of the cutter (.094) to the dia of the part the was touch off of (1.400")
to get 1.494". Divide this value by 2 to get the "Z" depth of .747". The slot was cut to the depth of .554" in "X" on center with the part.






While leaving the part in the jaws of the chuck I have mounted to my rotary table, the rotary table was now remounted in the vertical position on the mill table. The bottom face of the RT is indicated square to maintain realtive alignment. 2 holes were drilled in the part on .550" centers for clearance for 8-32 mounting bolts. To mill away the extra material not needed and to make the part look better 2 cuts were made on the flange portion of the part to leave a boss .800" wide.






I did a small layout on the computer using cad to give me a blend angle of 27 degrees. The RT was now rotated in 5 degree increments and sweeping cuts were made until I reached 27 degrees on both sides of my zero.






The mounting flange will be .187" thick so the cut was made deep enough.


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## Dave G (Jan 7, 2012)

All I need to do now is to face the part to length and turn a .562" dia stopping at .440" from the face. To be able to clamp on the .562" dia turned in the first op I needed to insert a scrap piece of matl in the .375" dia hole to support the walls and keep them from collapsing. Once this was done all Ineed to do is to blend the radii on the ends ofthe flange and for this I turned up a file guide the located off the mounting holes. 






Heres a pic of the 2 guides with the corners radiused with a file and then sanded on a sanding plate.






Because my lifters will be .375"dia I figured I'd use automotive valve seals on the lifters to help sealing.


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## metalmad (Jan 7, 2012)

Hi Dave
I wish Id read this before I made the exhaust flanges on my Wallaby,
Oh well theres always next time :big:
Fantastic as expected.
Pete


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## coopertje (Jan 9, 2012)

Very nice work Dave :bow: :bow: :bow: 
You sure know how to use your tools! Looking forward to your next post.

Regards Jeroen


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## Dave G (Jan 10, 2012)

Thanks guys, I appreciate the support. I had to turn up the lifter bodies next. For these I used a piece of 4140 that was preheat treated to 32 Rockwell C. After turning to within .002 of finished size on the OD I used a square Arkansas honing stone with plenty of oil to stone the surface to within .0005" of finished size. To finish I used 320, 400, then 600 grit paper to bring the surface to a nice polish. After parting them off from the lathe and finishing to length I placed them in my square 5-C collet holder in the mill vise. The lifter was indicated to find center by sweeping over each side. Here I am using my edge finder to find zero in "X".






After finding the edge I moved over .1875" and drilled then reamed a .125" dia hole for a dowel pin in the lifter.






Now I need to cut the slot for the roller. For this I used a 3/32 wide slitting saw mounted on an arbor. The table of the mill was raised until the cutter just touched the part and then "Z" zero was set. I do this with the spindle of the mill in neutral and rotating the cutter by hand. I want this slot to be wider than the slot in the lifter guide to avoid interference at assembly. 2 cuts were made with there being .004" difference in "Z" height.


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## Dave G (Jan 10, 2012)

The lifters were deburred and repolished in the lathe and then cleaned. Other than needing a dimple in the end of them for the pushrod they are finished. Next I will need to make the rollers. For these I used a piece of O-1 drill rod as I want to flame harden them for wear. The stock was chucked in the lathe and turned to within .002" of finished size and then finished to size as before. I drilled and then reamed a .126" dia hole for the pin and then parted them off. I laid them on the surface grinder with the finished side down against the magnetic chuck and blocked them in. The rollers were now ground to thickness. 






Heres a pic of the lifter components together. On the right are all parts that will make up the lifter assembly and on the left it is assembled.


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## willburrrr2003 (Jan 10, 2012)

All from the top of your head...WOW :bow: :bow:

Regards,

  Will R.


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## Dave G (Jan 11, 2012)

Now we need to ream a couple of holes in the gearcase for the lifter guides. This pic is of me indicating the roller bearing hole to find zero.





These holes will need to be .5625" dia. First we need to spot drill with a 1/2" spot drill.







A pilot hole is drilled.






Drilling a 35/64 hole for the reamer.


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## Dave G (Jan 11, 2012)

Now the hole is reamed with a .5625" reamer.






There are 2 locations for the lifter guides so the other hole was reamed as before. There will be 2 8-32 holes tapped for each lifter guide. This pic shows the locations for these being spot drilled.






I want these holes to be blind so I can keep leakage to a minimum. The tap drill was placed in the drill chuck and lowered until it touched my 6" scale and the quill stop was set. The table was raised to leave .04" in the bottom of the hole before breaking out of the other side. These holes weredrilled at this depth now.


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## Dave G (Jan 11, 2012)

These 4 8-32 holes are tapped now.






After a good cleaning the flywheel shaft was inserted into the gearcase and 1 lifter guide and lifter was installed. 






This basically the same pic but with the lifter on the raised portion of the lobe. You can see the lifter protruding from the guide on the left.


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## Dave G (Jan 11, 2012)

A pic of what I have finished up till now. The flywheel on the right, the crankdisks on each side and the lifters on the left. 






I have a few things to finish up on the gearcase and will do these next. After this we will start on mounting some cylinders to this thing.


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## bronson (Jan 13, 2012)

I just found this build and read thought the whole thing. I have learned lots from your setups and how you go about machining the different parts. You do some very nice clean work, your engine is looking great can't wait to see the end product running.


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## Ruy (Jan 13, 2012)

Nice work, I am waiting to see your project finalized.


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## Dave G (Jan 16, 2012)

Time for the cylinder yoke now. A piece of 6061 al. was cut off and the sides were milled to size. The first face was milled with a facing mill and then the part was flipped in the vise and then faced to size and checked to make sure the faces were parallel. A .500" dia construction hole was reamed on center after the part was indicated to find center in "X"&"Y". The holes for the cylinders were bored next to 1.501" dia to leave .001" clearance for the cylinder liners. 







Each cylinder will be attached to the yoke with 8 10-32 capscrews. The counter-bored holes for these are drilled next on a 2" bolt circle.


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## Dave G (Jan 16, 2012)

You will notice that I sawed the corners off of the part before boring the holes. The ends of the part will have a full radius milled on them. If I were to wait until after I bored the holes to remove this stock my holes wouldn't be round anymore. Anytime I have to bore a hole to size, I make sure I remove the stock from around the hole first to relieve the stress. To radius the ends I had to take a piece of stock and tap 8 10-32 holes in it on a 2" dia bolt circle to fit the yoke. The stock was placed in the rotary table on the mill and indicated in. The part was bolted to the stock and the ends were milled using the rotary table to generate the radius. Both ends are done this way.






And a pic of the finished yoke. The cylinder holes are bored to size and the mounting bolt holes are drilled and counter-bored.


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## stevehuckss396 (Jan 16, 2012)

2 more holes and there wouldn't be anything left. Nice!


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## metalmad (Jan 16, 2012)

Hi Dave 
I can not wait to see how you add the cyls to the Crank Module.
keep it coming its looking great !
Pete


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## Dave G (Jan 23, 2012)

I need to make the supports for the yoke next. For this I found 2 pieces of CRS .5" thick. They were squared up on the mill and then surface ground to make them flat. I also ground the edges square using my angle plate the same as I did the gearcase. The reason for this is when I drill and ream the holes for the dowel pins I want them centered in the part exactly. The holes go in the edges of the parts and must locate the yoke correctly. After reaming the dowel holes and tapping the mounting bolt holes the part was set up in the mill vise to remove some of the bulk. To start with I used a ball end mill to give me a radius to blend to.






Next I clamped the parts to my angle plate that is bolted to the mill table. An angle of 30 degrees as used. The excess stock is milled away now on each end.


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## Dave G (Jan 23, 2012)

A pic of my angle plate. The array of holes are for placing parts at 5 degree increments by placing the dowel pins in different holes. I didn't make this angle plate, it was made by one of my former co-workers and I bought it at his sale last fall. I can see I will get alot of use out of it. 






I drilled and reamed the dowel holes in the gearcase to match the supports and drilled clearance holes for the mounting bolts. Everything was cleaned well and assembled to see how it looked.






And from a different angle. 






The cylinders and liners come next. The cylinders will be made from 6061 al and the liners from 12L14.


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## metalmad (Jan 23, 2012)

Hi Dave
I guess your a doctor who fan Dave :bow:
cos it looks like your making your own Darlek :big:
EXTERMINATE EXTERMINATE


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## Dave G (Jan 23, 2012)

I'm a big Who fan but I'm not too keen on Drs. Pete LOL Do Darleks have machine guns or Ray guns? If this thing doesn't run maybe I can sell it to a local fisherman to keep his boat in place. Anyways, theres alot of extra bulk on the supports and the yoke to come off yet. I will need to mount the hall effect sensor and a coolant pump to the supports at some point and then I will know where to remove the extra stock. The cylinders shouldn't take too long to make but the cylinder heads will be a challenge. I'm going to have to think about a base soon also. I hope you can get an idea of where I'm going with this thing now. Soon it will look more like an engine, I hope.


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## stevehuckss396 (Jan 23, 2012)

Whatever it turns out to be, i'm enjoying watching it take shape.


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## Dave G (Jan 29, 2012)

I got tied up with a paying customer for a few days so I haven't had time to do much lately. I did get the cylinders started.
Heres a pic of the boring of the cylinders. I bored the ID to give me a press fit of .0015" on the sleeve. 






I had to bore a groove to form a water jacket around the sleeve next. I used a boring bar with a grooving tool insert for this.


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## Dave G (Jan 29, 2012)

I went ahead and drilled and tapped the mounting holes in the cylinders next. The cylinders were setup in the mill vise and indicated true. The holes were located with the DRO after using trig to find the locations.






The cylinder sleeves were made from 12L14 steel. The ODs were turned to within .020" of finished size and the bores were finished leaving .002" to hone after assembly. After finishing the bores the ODs were finished to size and then parted off. The sleeves were put in the freezer overnight and the cylinders were put on my hotplate the next morning to warm up. The sleeves were slid into position in the cylinders with a light coat of Locktite and let to cool. 

Heres a pic of the cylinders installed in yoke. 






I'll start on the cylinder heads next.


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## coopertje (Jan 31, 2012)

Hi Dave,

Good to see you back on the engine. I am very impressed with your finishing, man look at the way the cilinders match to they yoke? :bow: :bow: :bow:

Regards Jeroen


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## Blue_Rock (Jan 31, 2012)

Hi Dave, she's looking real fine. Keep up the good work, a very interesting build with a great finish.


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## gbritnell (Feb 2, 2012)

Hi Dave,
Very nice work as usual. Now I'm starting to get an idea of what it's going to look like. Quite unique!
gbritnell


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## Dave G (Feb 2, 2012)

Thanks guys, I've got some work done on the heads and will post the pics soon. I got some more real work dropped off at my place last night which will keep me busy until early next week. I have a friend that works for his brother-in-law in a machine shop and when they get real busy they funnel a little work my way. I'm glad I can help as they have just started and are doing well so far. 
 After the heads are finished I will go ahead and make the valve cages, valves, retainers, etc. I will try to post the making of these components as I move forward. I haven't decided on a coolant system yet or where to mount it. What does the forum think, radiator, screen cooled or a coolant tank? My grandson just woke from his nap and he looks hungry so I have to go, Dave


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## Dave G (Feb 8, 2012)

For the heads I cut 2 pieces of 6061 al 2.5" in dia at 1.1" in length. I chucked up on the OD and faced the part then turned the OD to cleanup.






Next the parts were turned around in the chuck and faced to cleanup. I used 3 pieces of shim to keep the part from being marked by the chuck jaws. The thickness was measured in 3 places and then tapped witha small hammer until the faces were running true with each other and then the thickness was finished at .750". Before removing from the lathe I used a toolbit with a radius ground on it to form a radius on the corner.


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## Dave G (Feb 8, 2012)

The heads were clamped in the mill vise with the outside surface up supported by parallels underneath. The OD was indicated in with the spindle and the 6 bolt holes were spot drilled.






The clearance holes were drilled for the 1/4" bolts next.






A pic of the holes counter-bored for the capscrews.


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## Dave G (Feb 8, 2012)

While the heads were still clamped in the vise I drilled and tapped the hole for the sparkplug which is 10x1 mm for a NGK plug.
This pic is of the counter bore being milled into the head for the sparkplug.


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## Dave G (Feb 8, 2012)

I needed to make a fixture to mount the heads to for the next operations. This was just a block of CRS big enough to mount the head to machined square and ground flat. 6 1/4-20 holes were tapped on the correct bolt pattern to match the heads. 
The heads will be cooled with holes drilled through them. The holes will intersect the exhaust valve cage and will exit the head from the top. The coolant will come from a port drilled through the cylinder into the jacket surrounding the sleeve.






Once all the coolant ports were drilled the heads were flipped over on the fixture and remounted in the mill vise so the the holes for the valve cages could be machined next. After indicating the OD to find center the holes for the cages were drilled and reamed .3125" dia through. Next I used a 31/64 endmill to take out most of the stock for the cage itself going .625" deep
in both valve locations.


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## Dave G (Feb 8, 2012)

Heres a pic of the head mounted to the fixture upside down so the holes for the valve cages can be seen. I used a small woodruff key cutter to extend the slot for the coolant to surround the exhaust valve cage. Heres where I made my first big OOPS. When withdrawing the keycutter from the hole on the last part I drug it across the surface of the hole leaving a large void where coolant will leak. I have a replacement started and will finish soon. 







Heres a pic of the heads attached to the cylinders. I am going to open up the coolant lines some before I go any further. I was originally going to use 3/16 fittings but I think they will be too restrictive so I will open everything up to 1/4".


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## Brian Rupnow (Feb 8, 2012)

Dave, I've got to say, That is one very imaginative engine. You are doing great work, I'm impressed with both the idea and the quality of your machining.---Brian


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## Dave G (Feb 19, 2012)

Thanks Brian. For an update, I have finished my customer work and in the proccess I have managed to destroy a bearing in the head of my mill. My modeling work doesn't tax my machine much because of the small size of most of the parts but the last work I did had alot of extra stock so I kinda got carried away with some very large cuts to save some time. Well during one of these cuts my mill started to squeal in pain. I finished the job as the mill would still run and I was on the last part anyways. My son and I tore into it the other day and we found one bad bearing. Its the bearing that takes the axial load on the movable pulley on the variable speed. I have a new bearing on order at a cost of $106 and it should be here in the next few days. Hopefully the reassembly will go well and I will be back to the twin soon. 
 I have decided to redesign the heads a little. I need to remake one anyways so I will just start over. After making the first ones I didn't like how close the sparkplug was to the rocker arm. I will also use the 1/4-32 plug instead of the larger NGK. I didn't have much work in the first set of heads so not much is lost. I'm sure sitting at the computer and drawing them first would have helped but that would be too easy. I like to do things the hard way. I took one of the heads I will scrap and modified it for an example to see how it looks and I am happy with the results. 
 My mill should be back together this week so I can continue with the twin. Dave


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## Dave G (Mar 6, 2012)

It took a little longer than I expected to get my mill back together but it is finished and running better than ever. I went ahead and made a new pair of heads. In this pic I am milling away the area for the spark plug. Using a ball endmill will give me a radius in the corner. 






Before removing from the fixture I used a 3/32" corner cutter to round off the edge. I remounted the fixture in the vise so I could drill and tap the hole for the spark plug. A shallow counter-bore was milled in for the gasket to seat to.


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## Dave G (Mar 6, 2012)

The valve cages came next. They were made from aluminum bronze. A tough material but good for seats and guides. A piece of stock was chucked in the lathe and the od was turned to clean up. The end was faced and a .149" dia hole was drilled to a depth of 1.125". A 7/16" dia ball endmill was plunged into the part to a depth of .525" to form the bowl area. The guide hole was now reamed to size and the od turned to a finish dia of .501" to give me a press fit of .001" in the head. Before parting off my 45 degree seat cutter was used to cut a seat in the cage. After parting them off they were remounted in the collet in the lathe and faced to a length of 1.125". A .311" dia was turned on the end to fit in the .3125" dia hole in the head. The heads were then put on my hotplate and heated until the cages slipped into holes with no effort. A light coat of loctite was applied to the od of the cage. I made a pusher from CRS that slipped into the guide hole and pushed on the bowl radius for easier installation. A pic of the cages before assembly.


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## Dave G (Mar 6, 2012)

A pic of the heads wit the cages installed.


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## Dave G (Mar 6, 2012)

Once the cages were installed and the heads allowed to cool they needed to be set up so the port holes could be drilled. The heads were once again bolted to the fixture and mounted in the vise on the proper angle. The intake ports were drilled to intersect the cage with a 3/8" dia ball endmill. I used a 1/2-32 tap to make threads for mounting an extention onto the head. The exhaust ports were done the same way but were 5/16" dia and tapped 7/16-32 for an exhaust pipe. All 4 ports were done the same way.


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## Dave G (Mar 6, 2012)

The port extentions were next. They were made from CRS. I would have prefered 303 SS but I didn't have any large enough to do the job. They were turned to dia and a .500" dia was turned so it could be threaded to match the port hole. They were single pointed in the lathe and then the .375" dia hole was drilled and they were parted off. They were turned around and installed in the collet and faced to length. I bored a pocket in the face for an O-ring for port seal. A brass spacer was turned to size so it could be sandwiched between the extention and the head. This pic shows one head with the extention installed and one yet to be installed.


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## Dave G (Mar 6, 2012)

Heres a pic of the heads installed on the engine finished to this point. The round heads of the extentions will be contoured when the mating pieces are made. I will setup the heads next and drill and tap for the intake attaching holes. I don't like the exhaust pipes and once this thing runs I will probably change them.


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## AussieJimG (Mar 6, 2012)

It's looking good so far, I like the little brass spacers on the intake.

Jim


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## stevehuckss396 (Mar 7, 2012)

Way to go Dave! God I miss being in the garage. I haven't made a part in months.    Keep up the good work and I'l keep checking in.


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## Dave G (Mar 7, 2012)

Thanks guys, it was 66 degrees F today so no time in the shop. The nicest day in quite some time for us so I spent the day outside. Rain and colder tomorrow is the forcast so I hope to be in the shop all day. Dave


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## petertha (Mar 9, 2012)

Dave G  said:
			
		

> The valve cages came next.... and the od turned to a finish dia of .501" to give me a press fit of .001" in the head.



So if I understand from your posted subsequent step, you then heat up the head, insert the room temp (or chilled?) valve cage, they cool together & that interference fit is what maintains the valve cage in permanent position thereafter in operating conditions, right? No high temp locktite used? 

If so, how hot does the head have to be for this? (Im wondering about the cage taking on heat transfer quickly & therefore having to work quick getting it landed in position & not stuck short?)


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## miner49r (Mar 11, 2012)

Dave,
  I don't know how I missed seeing this build til now. Totally awsome.
Alan


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## Dave G (Mar 11, 2012)

The interference was .001" and the cages were .500" dia. I left the cages room temp and applied loctite on the OD. The heads were placed on a electric hotplate that I bought for the shop. I didn't monitor the temp of the heads but they got hot enough to discolor the cages after installation. The cages did slip right in and went all the way to the bottom of the pocket. I turned up a pusher that piloted in the guide hole and pushed on the bowl radius. I made sure I had a good surface finish on the walls of the pockets in the head and everything was deburred carefully to make sure there were no obstructions or voids where coolant could leak. I don't expect any leakage of coolant. I used loctite more as a lube and a void filler than a retaining compound. Normally you should leave a void for the loctite but I felt an interference fit would be better. Time will tell, I guess I'm just old school and don't trust loctite as a retaining compound in this application. The cage was inserted and pushed all the way to the bottom of the pocket with one motion, you only get one chance and if you stop before reaching bottom it will stop there with little luck of moving further. I figured if something went wrong I could always reduce the dia of the cages and loctite them in place as a second option.                                   
 Where I used to work we had some jobs where the press fit between 2 pieces was quite excessive, the smaller piece was put into a freezer we had that was used to stabilize parts after heat treat and was -100degrees F and the outer piece was heated to just below the temp that would cause permanent transformation of the structure. Both parts were usually hardened to 56 RC plus and were made from toolsteel. Putting them together usually wasn't too bad of a job but when they came back for rework no one wanted that job. Taking them back apart made for some tense moments. 
 Since you asked, I will try to check the temp of my hotplate soon and post the results. I know it will turn mild steel blue. Dave


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## Dave G (Mar 14, 2012)

My hotplate checked at 430 degrees F. I went ahead and made the valves next. A length of 303 SS was placed in the jaws of the lathe with enough stickout to finish the job. The OD was turned to .158 for a length of .5". My finished dia should be .1555" and will be finished when the last cut is made. After the first series of cuts to .5" I next turned the next .5" to .159" dia. Once this was finished I turned the last little bit to .159" dia. Heres a pic of the first cut finished and the second cut partially finished.






Heres a pic of the next cut which will leave the OD at .159" for the full length of the valve stem.


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## Dave G (Mar 14, 2012)

Heres a pic of the tool I use to cut my seat surface of the valve. Its a HS toolbit that was ground to a 45 degree angle and relieved by hand.


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## Dave G (Mar 14, 2012)

A pic of the 4 valves after parting off. The valves were inserted in the collet of the lathe from the backside and the keeper grooves were cut with a grooving tool. 






Once the valves are completed all there is left to do is to hone the seat surface. I do this by setting my toolpost of the lathe at 45 degrees, easily done by clamping my square head to the toolpost and indicating true. The valve stem is placed in the collet and the seat surface is inked up and a fine Arkansas stone is placed up against the toolpost as a guide and the carriage of the lathe is moved until the stone removes the ink from the seat. After stoning smooth the surface is further honed by wrapping a piece of 400 then 600 grit paper around a piece of keystock and polishing the seat surface using the toolpost as a guide also. 






I have found that this way works well for me and usually my valves will seat without any lapping.


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## Dave G (Mar 14, 2012)

The rocker arms come next. After squaring up the stock to size the stock was placed in the mill vise and the .250" dia hole was reamed to size. This for a bushing that the pivot pin will ride on. The other hole is reamed to .0625" dia for the roller pivot pin. 






Next I needed to mill a 5 degree angle on the bottom of the rocker so they were setup on a 5 degree angle using an angle block.
The pivot pin was indicated to find the location for the adjuster hole which is also on a 5 degree angle.






The center of the rocker was found by sweeping both edges with an indicator.


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## Dave G (Mar 14, 2012)

Heres a pic of the bottom surface milled to size and the hole for the adjuster being spot drilled.






A pic of the adjuster hole being tapped.


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## Dave G (Mar 14, 2012)

The end of the rocker that get the roller needs a groove milled into it. A 3/16" endmill was used.







Once the mill cuts were made the rockers needed to be radiused on the die filer. I used the belt sander to rough the surfaces in and then went the die filer and then finished with paper. A few clearance cuts were needed for the intake valve and then the rockers were debuured and sanded smooth.


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## Dave G (Mar 14, 2012)

A pic of the rocker arms with the rollers. The rollers came from the scrap bin and were from an old roller bearing. They were drilled with a .0625" dia carbide drill for the center hole. 






The rocker stands will come next and then the heads will have to be modified for the stands.


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## stevehuckss396 (Mar 14, 2012)

Unusual looking rockers. I like em!


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## kuhncw (Mar 14, 2012)

Hi Dave,

I've been enjoying your build. You've posted a lot of good technique and I especially like the way you made the valves.

Regards,

Chuck Kuhn


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## petertha (Mar 14, 2012)

Dave G  said:
			
		

> ...rockers needed to be radiused on the die filer.



Sorry for the side-post, but that die filer machine looks really useful. Is it a shopmade masterpiece or a commercial unit?


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## Dave G (Mar 14, 2012)

Thanks Steve and Chuck. I'm glad you are following along. 

Peter, the die filer was made from a set of MLA castings. Metal Lathe Assesories. I bought the castings about ten years ago but I think they are still available. This has got to be one of my favorite and most used tools. Because I have no CNC capabilities, if I want any odd contours I have to belt sand them and then I go to the die filer. I normally finish with sandpaper but the die filer is a good medium between the belt sander and the hand work. I recomend this die filer as a good useful project. Dave


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## Dave G (Mar 31, 2012)

After a couple of weeks of warm weather, and getting nothing done in the shop, it has decided to get cold again which drove me back into the shop. I made the rocker stands and modified the heads for them but due to operator error no pics came out. Next came the intake manifold. 

I started with a piece of brass 1"x1"x1.4". After the piece was squared to size a window needed to be milled into the part. A 3/8" endmill was used after drilling a pilot hole first. 






The bottom of the piece needed to be milled on a 30 degree angle on each side. The piece was setup in the mill vise using my 30 degree angle block and then the piece was milled to size and then flipped over to do the other side.








While the part was still in this setup I needed to mill a .05" deep groove in each side for the side plates to fit into.


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## Dave G (Mar 31, 2012)

Now I needed to turn a spigot on the top end for the carb to fit into. The piece was setup in the mill vise and indicated to find center.
A .344" hole was reamed thru the top surface and then deburred. A piece of CRS was put into the chuck jaws of the lathe and an arbor was turned to size so the manifold would slide onto this arbor and would be secured with a 1/4-20 bolt. A radius tool was used to backcut the spigot dia. 






Heres a pic of all the manifold pieces before soldering them together. The center plenum will have 2 sideplates. The 3/8" dia tubing has the adapters slid onto them. The adapters have a generous radius on the entrance to the hole so the mixture has a smooth surface to flow around. This is also the carb I intend to use. 






A pic of the engine with the intake manifold in place before soldering. The combination square is for reference and is 6" long.






And a front view pic.






The tubes will be secured by retainer clamps that still need to be made and will be sealed with o-rings. After the manifold is soldered I will radius all the edges to smooth the look of it. I wanted to have a small plenum under the carb for better distributing the fuel mixture and I think this will work alright. We will see. 

Also in this pic you can see the rocker arms and their stands assembled to the heads. When assembling, I will need to install one head and then place the manifold and then install the other head.


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## AussieJimG (Mar 31, 2012)

That intake manifold is a work of art on its own. And the whole setup looks great.

I am still following with admiration.

Jim


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## CMS (Mar 31, 2012)

Now that's cooler than the other side of the pillow!!! Great work and thanks for the update. The warm temps here have kept me busy outside too, but today the rainy weather has given me some inside time, maybe I'll do something?!?!?!

Craig


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## Blue_Rock (Mar 31, 2012)

She's coming together very nicey Dave. Good tip on honing the valves in the lathe.


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## Dave G (Mar 31, 2012)

Thanks guys, I'm glad you're following along. Got some time tonight to do some soldering and finishing. The intake manifold pretty much finished.






It doesn't look like I'm going to have this thing ready to run before the NAMES show but it will be there. I am going to make the support legs next and then a base. I better get humping or I'll need a milk crate to set this thing on. Dave


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## Dave G (Apr 6, 2012)

The support legs were made from .5" thick 6061 al. They were squared up to size on the mill then clamped to my adjustable milling table. The table was set at 10 degrees and then the part was clamped to the table. I had scribbed a line on each end for reference. I used a pointer in the drill chuck and positioned the table with the line perpindicular to the x axis of the mill. Once the line was true the table was tightened to the mill table. One end on each support was milled to the scribbed line. 






To cut the other ends the table had to be set at 10 degrees in the other direction. The parts were inverted and milled to the line.


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## Dave G (Apr 6, 2012)

Oops, duplicate pic. heres the one I should have posted.






The top and bottom edges needed to milled at a 10 degree angle next. The adjustable table is repositioned to be parallel with the x axis but is still set at ten degrees. 






The mounting holes were drilled and then they needed to be relieved so the head of the bolts had clearance.


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## Dave G (Apr 6, 2012)

I had to disassemble the engine so I could drill and tap the mounting holes in the gearcase. While it was setup I also tapped a 1/16-27 pipe tap for a drain plug. I didn't want the legs to just extend from the gearcase at a 90 degree angle so they were milled at a 10 degree angle to give them a little wider stance and I thought it would look better. A pic of the engine with the legs attached.


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## Dave G (Apr 18, 2012)

Haven't had much time lately to work on the twin but I did get a few things done. I made the intake pipe clamps and the pushrods. I also found some time to make the fuel tank and it's holder.


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## Dave G (Apr 18, 2012)

A different view of the fuel tank and it's mounting.


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## Dave G (Apr 18, 2012)

The intake pipe clamps will sandwich an o-ring which will seal the intake pipes to the heads. The fuel tank was made from a piece of brass tubing that previously spent alot of time inside a drinking establishment ( bar rail ). I found a couple pieces of this at an engine show a few years back and I should of bought more of it. 

The cam seems to open the valves as they should when the flywheel is turned. I made the rocker arms so the pushrods and the adjusters are in a straight line at half of the valve lift. The Starbursts in the background were compliments of the Easter Bunny. Dave


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## gadabout (Apr 18, 2012)

Very Very nice!
So are the inlets atmospheric, I canna not see whats working them

Mark


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## Dave G (Apr 18, 2012)

Thanks Mark, the intake valves are atmospheric. My hopes are that this engine will be a slow runner. Dave


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## metalmad (Apr 18, 2012)

Hi Dave
I have a word for that intake manifold
Elegant. :bow:
Almost like a Darleks laser :big:
Pete


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## kutzdibutz (Apr 20, 2012)

A piece of art! Truely!
I'll be ashamed to post anything myself... :hDe:
(but will do anyways...)

Cheers, Karsten


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## Dave G (Apr 22, 2012)

Thank you Pete and Karsten for the kind words. Well I made it home from NAMES in one piece but alot poorer. I had at least a dozen gentlemen stop and recognize my twin from this forum this weekend. I thank all of you for the support and the interest you have in this project, it does help in the motivation dept. Its nice to know you are watching the progress. 

With the weather getting better I will have less time available to work on it, but not much more needs to be done before it makes it's first attempt at running. Although I hope for a nice and warm spring I will have something to keep me busy on the bad weather days. If I get anything done I will post it. Dave


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## Dave G (May 23, 2012)

I've had a little time to work on the twin lately so I started the connecting rods. I milled 2 pieces of 7075 al. to size and then reamed a .750" dia hole in one end for the big end and a .281" dia hole for the small end. These are undersize and will be finished last. A stub arbor was turned for a sliding fit with the .750 dia bore and then tapped 1/2-20 for a clamp bolt. 

The arbor was then clamped in the rotary table that is bolted to the mill table. The arbor was then indicated to find center and then a .500" dia endmill was used to contour the big end of the rod. Before mounting on the arbor I scribed lines for reference when milling the radii. The big end was then milled using the rotary table. The cuts were made from line to line.


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## Dave G (May 23, 2012)

A pic of the 2 rods with the big ends contoured.


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## Dave G (May 23, 2012)

Once the ends were done I needed to make a cut with an endmill with a .030" radius on it to the depth of the beam.

Both rods were done on both sides for a total of 4 operations.


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## Dave G (May 23, 2012)

The beams of the rods will be .375" thick so the cuts were made accordingly.


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## Dave G (May 23, 2012)

The small ends needed to be done next. Another arbor was turned to fit the .281 dia and then tapped 10-32. The arbor was once again clamped in the rotary table in the mill and indicated in. The small end of the rod was now milled to the correct radius and then the relief cuts were made as on the big end.


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## Dave G (May 23, 2012)

A pic of the rods up to this point.


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## Dave G (May 23, 2012)

Now I clamped the rods in the mill vise to mill the beam down to the correct dimension which should connect the relief cuts made before.


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## Dave G (May 23, 2012)

I couldn't figure a better way than to make fixture for the final cuts on the beam. What I need to do is to connect the 2 tangent points on each end of the rod. The fixture was just a piece of CRS that I ground to finish the top and bottom surfaces. The edges were milled parallel so it coukd be clamped in the mill vise. The fixture got a .750" dia reamed hole .375" deep and then tapped 1/2-20 and then the other end got a .281 reamed hole .375 deep and then tapped 10-32.         2 sleeves were turned to fit the rods bores with clearance holes for mounting bolts. One being 10-32 and the other 1/2-20.

The rod was mounted on the fixture and then the vise was loosened from the table so I could tap it around for alignment.
An indicator was used to find the low spot on one radius and then the radius was picked up on the other end and the fixture was tapped around until I got the same reading on the indicator on both radii. The vise was clamped to the mill table and The beam was milled to size with a .500" dia endmill. The rod had to be flipped on the fixture to cut the other side and both rods had to be cut.


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## Dave G (May 23, 2012)

The bores in each end needed to be sized next. They were clamped to the table and the holes were picked up with an indicator. The small ends were reamed to .3115" dia as the wrist pins will be press fit in the rod. The big ends were bored to .8125" dia for the roller bearing shell.


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## Dave G (May 23, 2012)

The small ends needed to be reduced in width and this was done in the mill vise. The rods were smoothed all around with emery paper and then the bores were touched up on the sunnen honer to make sure they were round. A pic of the finished rods.


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## Don1966 (May 23, 2012)

That is by far some beautiful work of art. I love the way you document and photo you work. You are a true craftman Dave. Thanks for sharing this journey with us.

Regards Don


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## stevehuckss396 (May 24, 2012)

Hello Dave!

Just wondering why the top of the rod is flat, clearance issue?

Everything looks great!


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## Dave G (May 25, 2012)

Can't get anything past you Steve, actually the piece of stock I had was only this long. I didn't want to short myself on the big end as it sees more stress than the small end. No trade secrets here, just using what I had. Thank you Steve and Don for the support. I finished the head gaskets yesterday, just a few more pieces and then the final assembly. 

It's starting to get warm here so I might get some time in the shop as it is air conditioned. Dave


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## gmac (May 26, 2012)

Geezzz Dave, you're no fun. I noticed that too - you could have at least told us in your spare time you're an engine designer for the Ferrari F1 team and that's how a REAL conrod should look .... 

Great work, keep it coming!

Cheers Garry


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## d-m (May 26, 2012)

That is what I'm talking about just an outstanding ideal and for a project and a informative wright up. I have learned an so much and made a new cool tool (angle plate ) 
Thanks Dave 

Dave


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## Blogwitch (May 27, 2012)

Dave,

Even though I haven't chipped in before, I am following along avidly awaiting your next steps.

I am really loving how you are showing the old school means of achieving things, well documented and shown.

People should learn a lot from your posts just by reading and understanding what you are achieving.

Great work :bow: :bow: :bow:


John


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## Dave G (May 27, 2012)

Garry, Dave, and John, Thank you for the support, it is nice to know you are following along. Like I have said before, I was reluctant to post this build as my first one on the forum but now I feel I made the right choice. Edison said he had no failures, he learned something from everything he did. I try to keep this in mind when designing and building things. 

I ran a 4 axis Mazak machining center when I was last employed so getting back to the old school methods is kinda refreshing for me. I have no CNC capability now so everything must be done the old way. As this is the world in which most of us work on our engines, I'm glad my methods are of some help to others. I find that I make alot of fixtures for making parts. I try to design my fixtures so that they can be used more than once and for multiple parts. Thats my Lean training kicking in, LOL. I do wish that I had a Mazak at my disposal though, I could get alot more done. 

I hope my postings will help the new machinist in his quest for which tools to buy or make and the way to use them. I'm just like everyone else, I dislike having a tool I will only use once, I would rather spend my money on a tool that gets used often.

I will continue to post my progress as it happens, kinda spotty these days but I am getting fairly close. Dave 



P.S. Garry, I do build old beat up Mopars and take them to the dragstrip often. Not Ferraris or F1 mind you but still alot of fun.


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## db6261 (Jun 3, 2012)

This had better win project of the month when it's finnished! Extremely fine work Dave!!!


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## Dave G (Jun 29, 2012)

Its been too long since I've posted any progress, I spent some time in the shop the last couple of days and made the 2 crank pins. These were made from a piece of 6AL 4V titanium I bought from the scrap man a few years ago. It doesn't machine that bad, slow speeds and proper feeds with sharp tools did the trick. I used titanium to keep the weight down and for the strength and I have been saving the stock for a special occasion and this was it. I didn't take any in process pics as it was a fairly easy job to turn them up. The thread is 3/8-24 unf which will thread into the crank disks. The threading was done by single point and made to fit the mating piece with a close fit. I machined a 7/16" hex to be able to tighten them at assembly. 







The crank pins will support and tighten on a hardened sleeve made for roller bearings. The big end of the rod will have a needle roller bearing pressed into it and the roller bearing will rotate on the hardened sleeve.

The wrist pin will be a press fit in the small end of the rod. This is the first time I will try to use a pressed pin here. I need to modify the pistons to have a surface to rest on when the pins are installed. An undercut should do it. This I will do next and take pics.

After I mod the pistons I think I will have everything made to be able to assemble the engine and give it a try. Alot of cleaning first and then a trial fit of all the pieces. I hope to be able to do this soon. Its getting close so I will take pics of all the components before assembly. Dave


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## kuhncw (Jun 29, 2012)

Nice work, Dave. This is not only an exotic design, but exotic materials too. I'm looking forward to seeing your twin run.

Regards,

Chuck


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## Chitownmachine (Jun 29, 2012)

Beautiful work.....your finishes are amazing....how do you get such a fresh clean finish on all your parts? whats yer secret??


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## Ogaryd (Jun 29, 2012)

Really a cool design Dave, I love how you tucked the intake valves under the exhaust rocker.

   I'm enjoying every minute of your build.

                                                Regards Gary


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## Don1966 (Jun 29, 2012)

I am really enjoying your built Dave, I am still following along waiting on your continued progress. :bow:

Don


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## metalmad (Jun 29, 2012)

Hi Dave
Its looking amazing Mate :bow:
Pete


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## Dave G (Jun 29, 2012)

Thanks guys, I'm glad you are enjoying it. 

With aluminum I use sharp tools made from hi-speed steel and steady feed. I hone my tools with a stone after grinding to shape. The naked eye can't tell if your tools are sharp or not, at least mine can't. Normally no sandpaper with al. after turning. With steel I use carbide insert tooling and a new one for finishing. If I can't get a good enough surface from turning or milling I will either stone the high spots off and then sandpaper it to death. The beams of my connecting rods were milled then I used 240, 320, 400, and 600 grit to sand out the previous grits scratches. I try to get as good of surface finish when machining as I can so it is easier to finish with sandpaper. I have rubbed my fingertips to nubs trying to get something to look good before so I try not make myself more work than I have to. Sometimes that is what it takes though. 

With brass, lots of sandpaper. I think its actually fun to shape brass by hand. Hard on the fingertips though. 

I guess with finishing it is where you finally say thats good enough or your fingers quit working, which ever comes first. In the last couple of years uncle Arthur Itis has taken up residence in my knuckles and the fingers will quit working before that good enough point gets there. I'm glad the camera does a good job of hiding it. I still get a kick out of shaping a piece by hand after machining but it doesn't come as easy at it once did. 

I just recently bought George B's v-twin drwgs because everyone should have one in my opinion. I love how he shapes the crankcase and other parts by milling away the stock then finishing the surfaces by hand. A sign of a true craftsman. I want to build this engine in the worst way and will find a way to do it. I just have to talk my fingers into it. 

I'm glad you're still with me on this one, Dave


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## Chitownmachine (Jun 30, 2012)

Dave, Thanks for the info!! I'm gonna work on sanding till my fingers are nubs!  Looking forward to the rest of the build!!!


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## Dave G (Jul 4, 2012)

I still need to modify the pistons yet, but I took a pic of all the components that are finished up to this point. 






I think I have everything made that will allow this thing to run. Still need a base to mount it to though. The base won't be anything special until it runs and then it will get a new one. If I can make this thing run it will then need a coolant system made for it. That won't happen until the fall. Dave


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## ShedBoy (Jul 5, 2012)

That is a beaut looking pic Dave. Looking forward to the vid.

Brock


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## stevehuckss396 (Jul 5, 2012)

Good stuff!!


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## Don1966 (Jul 7, 2012)

Beautiful looking parts Dave and quiet a few of them. Hope to see it assembled and running soon. Great work as always and thanks for sharing.

Don


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