# Bogstandards "Paddleducks" engine



## shred (Mar 1, 2009)

It's sort of traditional when I get a new machine to use it to make a simple engine to get a feel for how it works and what all the knobs do.

This time around I decided to try Bogstandard's "Piston Valve Engine from mainly junk materials" -- it's a little 2-cylinder twin engine that I'd been meaning to give a go for a while now. Plans and text are posted in the download section. With any luck I can finish it in less than the year the my loco took 

Of course the plans are metric and while the new machine has a DRO that will speak metric, I still don't have metric drills, reamers or stock material, so I get to adapt and improvise. So far that's been limited to switching the bore for 3/8", changing the piston rods to 1/8" with 5-40 and 4-40 threads as well as 3/16" crosshead guides.

Anyway, after Day 1, I got the block bored, the glands, caps and piston made, plus started in on the cross head blocks and broke one tap. We'll see how square everything ended up later..


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## malcolmt (Mar 1, 2009)

Hi Shred

"after Day 1, I got the block bored, the glands, caps and piston made, plus started in on the cross head blocks and broke one tap.!

I would call that almost prolific.

Nice work, I'm looking forwards to watching this come together. 

Kind regards

Malcolm


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## ozzie46 (Mar 1, 2009)

I also plan to build this engine. I have even obtained some cast iron window sash weights for the cyls. ;D

 Ron


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## Philjoe5 (Mar 1, 2009)

Thanks for the progress report. I'm with Malcolm - seems a lot was accomplished in 1 day especially with new tools and converting metric, :bow:

Cheers,
Phil


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## deere_x475guy (Mar 1, 2009)

Shed I have been eyeing that engine for a long time now. I am looking forward to seeing your progress.


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## shred (Mar 1, 2009)

Well.. I did have the entire day to play.  Normally I do well to make a part or two per day, what with the rest of life intruding and all.


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## shred (Mar 1, 2009)

Tried to hack the crossheads out of the blocks today. That didn't go so well. Looks like the piston hole is considerably off-center. Oh well, it's good practice with the new machine. I'll carry on a bit and see when I need to make a new set. These still have a lot of ugly left in them, so it wouldn't be a big loss.

One thing I did notice was the resemblance to a certain common household plumbing fixture from certain angles. I believe our British cousins might refer to it as a 'bog'. If that was a sneaky joke by John, it was a very clever one 




One thing that did turn out ok was rounding the parts using some filing buttons on the belt sander. If you've not run across filing buttons, they're easy and useful for this sort of thing-- take some drill rod, turn it down to the size you want, drill it out, then harden it, but don't bother tempering-- then you have some super-hard (but brittle) buttons. Just the thing to slide up next to your part on a rod and file or sand away. When the level of the part gets down to the level of the buttons, they are too hard for the file to dig into, so it stops cutting. If you are using a sander, make sure they can roll or they will get ground down eventually.




Here's the crossheads with some rounding applied--


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## Bernd (Mar 2, 2009)

Hey Shred,

Those holes that are off center, how about soldering a plug in them and recenter the hole?

Bernd


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## shred (Mar 2, 2009)

Bernd  said:
			
		

> Hey Shred,
> 
> Those holes that are off center, how about soldering a plug in them and recenter the hole?
> 
> Bernd


That was one thought (though a little trickier now since I'd have to use the bores to align the work), but really they're ugly enough that I think I may just redo them and try to make them look nicer next time.


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## bentprop (Mar 2, 2009)

I'm greatly interested to see how you get on with this engine,Shred.I started one last year,but ran into so many problems,I gave up ,and started something simpler.It was probably a bit too ambitious as my 2nd engine.The piston rod holes in mine were in the right place,but the support rods didn't line up with the cylinders in the block.I was on to my 3rd bottom plate before I put it aside.I don't know where I went wrong,probably somewhere during the marking out.
I'll revisit this engine when I have a bit more experience,as it is a nice engine to see running.


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## chuck foster (Mar 2, 2009)

looking good so far shred 8)

i will be watching this build very close as i have thought about building one of these engines myself (after i get the other 100 projects done) :big:

is this engine going to be used in a boat or just as a display?

chuck


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## shred (Mar 2, 2009)

aermotor8  said:
			
		

> looking good so far shred 8)
> 
> i will be watching this build very close as i have thought about building one of these engines myself (after i get the other 100 projects done) :big:
> 
> ...


I'm probably just going to display it, not having a suitable boat or desire to get into yet another hobby; boatbuilding (aside; I'm always faintly amused by the occasional justifications I see in plan sets like some of Elmers Engines "this could be used in a model boat".. as if the model engine itself weren't enough justification to make it). I'm considering building a small boiler for it since I had a lot of fun playing with live steam on my little loco. That might make an entertaining pair.


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## chuck foster (Mar 2, 2009)

your little loco looks great and from what i see you had allot of fun with that build 8)

chuck


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## shred (Mar 15, 2009)

Quick update-- my mini-vacation and resulting Evil Honduran Chicken Flu kept me out of the shop, but after standing up for 3 whole hours in a row yesterday, I felt well enough to visit a friend's CNC shop this afternoon. He gave me a couple used-but-still-ok end mills (what I think of as 'big' ones; 1/2" and 5/8") that I used to crank out a couple more brass blocks to make another set of crossheads from. That's it so far... more to come.


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## Philjoe5 (Mar 17, 2009)

Shred, thanks for the update. I have downloaded Bogstandards build log so I'm watching this thread with interest.

Cheers,
Phil


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## shred (Mar 17, 2009)

Got the 2nd set of crossheads done tonight. Much better than the first set. They still need a date with the bling-fairy, but are good enough as-is for me to move on to the next part.

Cutting brass goes a lot faster when you can plow through it with a 5/8" end mill.


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## shred (Mar 22, 2009)

Made a little more progress on the 'ducks engine. Got the top plate made, partly blinged and tapped 22 #2-56 holes in the block.




The engine turning was a bit of an experiment but it came out nice and is pretty easy (though a little tedious)




I did it on the mill just to play with the concept and quickly realized the way to index the plate was to ignore the DRO and just use "one crank" of the X handle per swirl, then one crank of the Y at the end of a row. Even though it wasn't 100% precise, it's tough to tell by looking at it how rough the indexing was-- I was off by a 1/8 turn several times.

I used a little DremelTM craytex bit, but that broke right at the end, so I'm going to try some other options next (annoyingly, Dremel has discontinued their little metal end-brush that I was about to try). I have several craytex sticks but would need to whip up a holder for them since they're way too whippy as-is. Bogs uses grinding paste, but I'd rather not mess with getting that all over the mill.


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## Metal Butcher (Mar 22, 2009)

Your project looks really good! :bow:

I have been following your progress with great interest.

Would like to give it a try someday when I feel I'm ready for a more complex build.

In your thread there is mention of the plans in the down load section, but I can't find them. Is that were you got them?

-MB


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## shred (Mar 23, 2009)

Metal Butcher  said:
			
		

> Your project looks really good! :bow:
> 
> I have been following your progress with great interest.
> 
> ...


Thanks. The downloads section seems to be broken right now, but I think I got them from a link off some site called 'rake60.com' or something 

Scope through this thread: http://www.homemodelenginemachinist.com/index.php?topic=615.0 -- the links are there along with a bunch more pics of the originals (note that contrary to what I wrote then, I'm building this using the same de-metricification I used on the Slightly Loco-- holes, threads and stock like drill-rod are converted to a convenient imperial size, the rest remains metric-- it's easy enough for me to switch digital calipers and the DRO to metric; I just bail out on drills, fasteners and threads, hopefully making a note of it so I don't hose myself later on.


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## shred (Apr 5, 2009)

I got a little time on the Paddleducks engine today. Didn't make much beyond the crosshead rods, but I did a lot of tweaking and assembly. The top end is all assembled and running on air (a squirt in the appropriate port slaps the piston & crosshead to the other end). Unfortunately the battery was dead in my shop camera, so no pictures of any operations (note to any following along.. you might want to make the piston rods a few mm longer to easier accomodate the cross-head lock nuts. I will be needing some thin ones later on)

for future reference and other de-metricifyers, I went with #2-56 for the crosshead bars and #4-40 for the piston rod thread. The crosshead rods are 3/16" and the piston rod is 1/8".


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## Blogwitch (Apr 5, 2009)

Shred,

You are doing a wonderful job.

You have the crossheads done, they are the hardest pieces to make, the only other critical bit is the control valve. So now you have this bit done, the rest should be plain sailing.

Blogs


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## Paolo (Apr 6, 2009)

A really wonderful Job.... :bow:
Paolo


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## shred (Apr 7, 2009)

Made four little square blocks of brass for the bearing blocks today. Gave me something useful to do whilst on a two hour conference call with Asia that I only needed to be involved with occasionally (since I have to talk, it means I have to turn off the machines, making a nice safety interlock)

The next bit of thinking revolves around de-metrification; contributions and idle thoughts welcome--

Originally I thought to have the main crank shaft be 1/4" drill rod, but looking at the little raw bearing blocks (for some reason whenever I work in metric my mental image of the parts-to-be-made is always about 25% too large) it seems that 3/16" would be a better fit to the originally spec-ed 5mm (those are my options-- 1/4" and 3/16", so the big end pins will likely be 3/16" as well)

I don't think that matters much except looking at the eccentrics, the crank bore would be very close to the eccentric strap with a 1/4" shaft. But that eccentric strap is 14mm and I'm not likely to make 14mm eccentric straps unless I have to. 1/2" (12.7mm) and possibly 9/16 (14.3mm) are far more likely to be in my drill repertoire. Of course if I do that, then I may have to redo the eccentric geometry because I suspect it may throw the throw out. 

Hmm.. now I get to think on which is easier, boring the holes or redoing the eccentrics? Time to go see if Marv has an eccentric-strap design program


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## shred (Apr 8, 2009)

Got the bearing blocks cranked out of the squared blocks I made yesterday and a start on the baseplate. 

About halfway through I remembered the camera was now charged.

Here's a decorative contour pass after drilling, reaming and tapping (#2-56) the blocks. Not for nothing does it slightly resemble the Alamo 
Note the vice stop. Most handy when doing 4 sets of bearing blocks. Zero the DRO on it and the fixed jaw and it really helps speed things along. In this case I just set the corner rounding bit where I wanted it once and kept putting blocks in the stop, cut, flip and cut again.





Over to the lathe and being bolted onto a headless #10-32 bolt for the boss cut (3/16" crankshaft ~= #10 bolt)




If you lock everything but the cross-slide down, and set the infeed once with the compound you can crank 'em all out quickly if you were reasonably careful with the width (I used 3/8" material which worked nicely as a just-under 10mm width) -- just bolt them on, face to the nut, flip, face to the nut and go get the next one.




​
After checking that the crank bore is in the right spot, it's time to make the baseplate. There is an important lesson here for those inclined to take shortcuts. This is the fourth baseplate of the night.




Here's the story-- Since I'm using the vice stop and DRO, I re-marked Bogs baseplate drawing to be origin in one corner instead of the datum line on center as he had it so I can just drive the DRO to the coordinates without fussing around marking-out. I have a decent stash of irregular 1/8" Alu sheet, so I grabbed some and hacked off a bit (plate #1). Squared up the rough cuts and aw, rats.. I overcut it squaring... it's 99mm long.. 1mm too short. Well, I could probably use it as-is, but I have a lot of Al and it didn't take long to get to this point, and I'd like to do it right, so off to the bandsaw.. since the first plate is just a little small, slap it in a clean area of the Al sheet and draw around it with a marker to get a cut line. Cut slightly outside the lines to be sure I have enough for squaring. (plate #2). Square that up all nice and neat, 50mm x 100mm. Stick a spotting drill in the mill and away we go spotting the hole locations. Drive Y to 5mm and run along X along spotting them as needed. 5mm.. 15mm.. Third location out and I spot somewhere that's not supposed to have a hole as I'm going off the X and Y at the sides of the drawing and that particular X is for another row. Crud. Well, it's on the edge, I can use it as an extra support bolt. All I have to do is remember to drill one over on the other side as well. Keep going. 45mm.. <spot>... 99mm...<spot> 105mm... <erk, wait.. one hundred and what?!?> This plate is 100mm long. Look at the drawing again. Plain as day, it's 50mm x 110mm. Aw [email protected] Time to go cut some more stock. Since we're a little torqued with ourselves today, slap down the old one in some of the now-diminishing available sheet, outline it and cut it out... (plate #3) to realize immediately that we forgot to add the 10mm to the length. Son of a... one more time, but this time with plenty of extra rough (plate #4), and for good measure, we'll actually mark it out this time. And mark where the holes aren't supposed to go.. This time, so far, It's a success.

So now you know "the rest of the story"  

No way I'm going to try cutting the crank clearance slots in the baseplate tonight..


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## Kermit (Apr 8, 2009)

:big: HAHA  Cut it twice and it was STILL to short!   :big:


That's never happened to ME.  (Everyone ducks for cover and eyeballs the sky for lightning bolts)


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## Shopguy (Apr 8, 2009)

Coming along very well. Excellent photos of showing making the pillow block bearings. 8)
Regards
Ernie J


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## Maryak (Apr 8, 2009)

Shred,

Your engine is coming along very nicely. :bow: :bow:

Your recycle box is doing the same as mine, recycling the recycled. ;D

Best Regards
Bob


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## shred (Apr 8, 2009)

Yeah, I made two nicely squared pieces and one rough chunk for the scrap, er, "small aluminum pieces" box . The squared ones will likely get used before long-- too easy to clamp them up and hack away for some little task. Maybe if I get really bored someday I should go through the scrap boxes and square off the really baroque bits and pieces...

Frank Ford has a piece on his web site about putting a hole through nub ends of lathe stock to use as general purpose spacers. Over time I've faced off and drilled a handful of short-ends in standard small-tap shank sizes to make handy little tapping blocks that can be easily modified for special purposes.


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## bentprop (Apr 8, 2009)

I feel your pain,shred.I've done exactly the same thing,but with the top plate 
I've put the whole thing aside until I either get better at making stuff,or kick the bucket and some other poor slob gets to puzzle over my cock-ups,eeerrrrr,modifications :big:
regards,Hans.


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## shred (Apr 10, 2009)

Got the slots for the cranks cut without excess drama, after a couple rounds of cut-and-try, though I did notice one glitch when I was editing the photos that will get fixed.




The reason for the mass amounts of Dykem on the blocks is I thought to bolt the blocks down, hose down the assembly with spray layout fluid, wait for it to dry and cut to the white spaces. That didn't work as well as I hoped. Too much flaking and oozing around and under the blocks.

If you do these with a DRO, keep a pad of paper and pencil handy to write down what coordinates you're working on and getting back to.


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## Kermit (Apr 11, 2009)

I assume you mean the little wave up near a corner of your cutouts?

 ;D  I've heard this before and been eyeballed as some kind of saboteur by the machinists at work. "That wasn't there when I gave this to you".

 

Damn my eyes, 8)
Kermit


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## shred (Apr 11, 2009)

Kermit  said:
			
		

> I assume you mean the little wave up near a corner of your cutouts?
> 
> ;D  I've heard this before and been eyeballed as some kind of saboteur by the machinists at work. "That wasn't there when I gave this to you".
> 
> ...


 Yeah, that was on the side that was towards me in the vice and I must have missed running the mill all the way from side to side when I deepend that end. As I remember there was some debate in my mind as to if I was going to 37mm or 37.5mm for that particular space. Another reason two keep good notes while you're working!


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## shred (Apr 11, 2009)

Spent most of the day playing outside, but got the flywheel done (and fixed the mis-cut).




One more good use for the vice stop and DRO (and you don't even need the DRO)-- since it's zeroed on the fixed jaw and edge of the stop, its easy to find TDC to drill the set screw hole.

Measure the flywheel width and thickness, set it on parallels against the stop so the widest part of the wheel hits the stop, then drive over to half the width and half the thickness, spot, drill and tap.


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## Kermit (Apr 12, 2009)

???&#160; How do you account for the thickness of the drill bit itself?

If you touch at the edge then go over to the center isn't the radius of the drill bit going to cause you to move over too far?

Expecting to feel stupid soon,
Kermit


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## shred (Apr 12, 2009)

Kermit  said:
			
		

> ??? How do you account for the thickness of the drill bit itself?
> 
> If you touch at the edge then go over to the center isn't the radius of the drill bit going to cause you to move over too far?
> 
> ...


This may not be the best way, but it's what I learned playing with CNC machines-- I zeroed with an edge-finder such that the spindle center is at 0,0. Drilling is then dial-and-drill since the center of the hole is the hole coordinates. 

I apply cutter size offsets for milling. That's sort of a nuisance with imperial cutters and metric measurements, but makes sense in my brain and isn't too bad with a shop calculator handy-- want a cut 5mm from the stop-edge? Drive the DRO over to (5mm + cutter radius) and make the cut. The same thing can be done with handwheels, but it takes a little more care and a lot more calculatoring if you've got imperial dials and are making metric parts.


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## Kermit (Apr 12, 2009)

shred  said:
			
		

> I zeroed with an edge-finder such that the spindle center is at 0,0. Drilling is then dial-and-drill since the center of the hole is the hole coordinates.



Don't understand a word of it. ???  (Kermit leaves for google book land in order to add this piece of appearantly much needed know how to his "pile" of pdf files)


Thanks Shred. "I'll be back!"


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## Metal Butcher (Apr 12, 2009)

Kermi, Its just a simple "wording malfunction." I breezed through using my secret speed reading method and understood completely.

My understanding: You simply zero out the dials and the spindle- center on the x-y edges of the work piece using a standard edge finding practice. Then you move in from both directions half the thickness and diameter of the work piece to find dead center. Then you drill or what ever at ground zero or 0,0 or the sweet spot, or home, or whatever you call it.

(When at that point I usually take a five second break to dance the Chubby Checker "Twist" before proceeding. Its help to sooth me and results in good accurate drilled holes. Don't laugh, try it some time).

Shred, you aptly named it, "Dial- and- Drill."

I like it!

-MB


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## shred (Apr 12, 2009)

Metal Butcher  said:
			
		

> Kermi, Its just a simple "wording malfunction." I breezed through using my secret speed reading method and understood completely.
> 
> My understanding: You simply zero out the dials and the spindle- center on the x-y edges of the work piece using a standard edge finding practice. Then you move in from both directions half the thickness and diameter of the work piece to find dead center. Then you drill or what ever at ground zero or 0,0 or the sweet spot, or home, or whatever you call it.
> 
> ...


That's correct. If I had a laser beam directly down the spindle, it would be exactly in the corner of the stop and vise jaw when the DRO says X=0 and Y=0. If I had a 3/8" cutter in the spindle and lowered the quill, it would cut a 3/8" hole centered on 0,0 (which would take a semi-circle notch out of both the vise jaw and the stop, so I avoid that). 

Drill holes are generally specified to the center of the hole and thus the center of the drill, so working off the center of the spindle works well-- no correction needed.

For side-milling to a dimension, you work with the side of the cutter, so you really want to know where it's edge is. You can zero off that, but that's kind of a pain since your zero is only good for the side of the cutter you zeroed on-- if you touched off on the right side of the cutter for example and then wanted to cut on the left side, you have to either touch off again or apply a correction. I just leave the spindle zeroed on the center and correct for all the sides. That way you can change cutters with abandon and not have to reset the zero, just change the 'correction-factor' you apply when milling, and that is constant for any direction you cut until you change the cutter (you do, however, need to know the cutting diameter of the cutter accurately enough to produce the desired results-- CNC machinists can get all wound up about cutter compensation, though for our kind of work usually good-enough is good enough.)

Here's a little crap-o-cad sketch that might help. The red dotted circle is a cutter zeroed on center-- a drill or end-mill, showing how for a drill hole, it cuts where it's supposed to (assume it's the appropriate size for the hole), but were I trying to mill to the 10 line, it would cut too much off.

MB: I will have to try the twist


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## Metal Butcher (Apr 12, 2009)

{Shred wrote:} MB: I will have to try the twist 



If you have a radio on as background, turning up the volume and taking a 5 to 10 second break before a critical operation is also beneficial. 
This technique is not limited to any song or dance. "Stepping away" to have a few puffs of a good cigar, or a breath of fresh air, etc, will also work.

Drill 2 holes and call me in the morning. :big:

-MB


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## shred (Apr 13, 2009)

Got a bunch done today as I had almost all day to run free in the shop.

Started out making the crankshaft webs. Got a piece of 1-1/8" hex brass and whacked it down to 28mm diameter. Then I sliced off some 6mm-or-so slices. To true them up and make them all 5mm thick, I bored out a set of soft jaws I had mounted on my Taig lathe chuck (it was handy and had soft jaws on it which are excellent for this sort of thing), faced the disks to 5mm and reamed the center hole. I had forgotten how useful that little thumb-screw carriage stop is on the Taig. Must make one for the 12x




Somewhere along the way I made a 3/16" toolmaker's reamer to help with the holes, so here's the disk stack on the reamer. It came in handy finishing the second set of holes.



The third hole is less critical, so I drilled them as a stack-- drill the top one, pull it off (otherwise it can get loose and climb the drill), then the next, remove it, next...




Reassemble the stack and mill the sides of the webs




Then two at a time on the rods for drilling and tapping #2-56 (the second web is only there to fill space so the vise stop doesn't hit the other jaw-- once the first was tapped, I flipped the set over and drilled and tapped the second web in the same location. The lower hex piece is a tapping guide that I made after seeing some of Marv's on here-- the bottom half is drilled for a small-size tap shank, the upper drilled and reamed for a 1/8" dowel pin. In use the dowel pin keeps it aligned and the guide slides down the pin as the threads are tapped. I usually turn it with my fingers on small taps.




Then back over to be slit with a slitting saw. You'll notice my saw didn't quite reach the small hole and I had to extend the cut a little with a jewelers saw. Lucky for me the ugly cuts are pretty tough to see once it's all assembled.




Then I drilled out a clearance hole for the squeeze bolt. This is where disaster struck. I had a piece of metal (broken slitting saw blade) in the cut to stop the clearance drill from breaking through beyond the cut, but it got a little out of place on one and before I could stop it, I'd put a clearance hole right through the web. Ack. Bogstandard wisely makes extra parts for reasons like this, but.. I'm lazy and didn't. So, make a new one or fix the old? May as well try and fix the old first. I scrounged up a little brass wire that fit ok and silver-soldered it into the side where the threads should go.




Cut off the excess and retap and you can't tell it was ever wrong (which means it's right ) The only way I know which was fixed is the fire scale and that will be gone soon.




Then on to the eccentrics. Since I'm not using 4mm material for the straps, I cut the slot to 3/16" which limits the available space for the set screw (mental note, make a good slotting/grooving cutter next time I have the cutter grinder going). I'll be putting in a flat-blade screwdriver #2-56 set screw later. I chose to try re-using the cut off bolt and nut from turning the bearing block bosses instead of tapping a rod as in Bog's instructions and it worked well.




Here's the crankwebs and rods and eccentrics and flywheel all test-assembled to see if it's all going to work. Amazingly enough, it all fit and turns with only a little effort.  Some running in and it'll be fine.


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## shred (Apr 14, 2009)

It's kinda late for me, so I'm just going to throw some pictures and a little text up and add commentary later as needed.

This post is about making the support columns. I experimented with blinging them up from the plan stock rods and made square fluted columns. I figured there wasn't a lot of metric on them to occupy my few free brain cells so I could play a little.

The first (well, second try, but first 'good' one) sample and raw stock for the next 3. Note they are extra long.





Here's why they're extra-long-- to give the vise something to hold onto at either end. The one in the vise has had one side cut, then flipped to the other to do the next two cuts with a 3/8" ball end mill. See the dark area in the middle bottom of the part where there's no material anymore. Were these cut to the 70mm final length, there wouldn't be much there to hang onto (see the next picture)




The final columns, drilled and tapped #4-40.




And test-assembled to get all of the parts made to date attached into one glob. I think they'd look better in brass, but I had no 3/8" brass square stock handy. I can always color them later at painting time.






(and one note-- I'm tending to illustrate items not illustrated in Bogstandards' book. So if something seems unclear, check there as well..)


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## shred (Apr 22, 2009)

Made the con-rods and pins, did some tuning and running-in and put a couple sleepers on the bottom for now.

Alas the fluted con-rod test part I made was deemed ugly and/or out of place on this engine and straight turned ones were used, so I still await a chance to play with Marv's latest program. Due to my de-metrification of the crankshaft pins to 3/16", the 6.5mm square dimension on the plans only had a very small amount of material surrounding the pins; maybe 1/32" either side, so I thickened the rods up a little at the big end to 5/16"x1/4" (the small end is on a 1/8" pin and is 3/16" wide-- You'll note a slightly different pin style versus the plans). The only trick was turning the round section on the con-rods without fussing with a 4-jaw chuck. I did that by milling the 5/16"x1/4" out of 3/8" round in a collet block. With a holding/turning nub on the end, it's no problem to round the shaft in the lathe.




Here's my Lego guy showing what we have to date and trying to sort the eccentric timing. It turns over well on an electric drill with good compression but is still a little stiff turning by hand. I expect that will loosen up with time.


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## Maryak (Apr 22, 2009)

Shred,

Looking very nice. :bow:

I like the lego engine driver. Now all you need is the Fat Controller ???

Oops - English joke. :

Best Regards
Bob


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## steamer (Apr 22, 2009)

Nice Build Shred! Can't wait to see her running on her own!......with a little help from Lego guy of course


Dave


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## shred (Apr 26, 2009)

Latest update-- got the valve blocks done. For the playing-along-at-home types, I went with #2-56 for the steam port threads, and #4-40 to hold the blocks on (aside: I don't know if drills, taps and screws are commonly available in 0.5mm steps in this size range, but if so, metric is the way to go for models this size-- several more options). The rest of the holes are whatever number drill was close to the right measurement in mm. The ports were cut with a 3/32" end mill and the spool valve bore is 1/4"

We're continuing the 'Alamo' bling style here with the rounding bit. At the moment they intentionally doesn't quite align with the top of the main block, on the theory I can always cut more off if I don't like it in the end. I'll be putting in nicer screws or studs later as well.


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## RobWilson (Apr 26, 2009)

Real fine looking engine your building :bow: :bow:
Rob


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## ozzie46 (Apr 26, 2009)

Shred would a 1/8 end mill be to big for the ports?

 Ron


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## shred (Apr 26, 2009)

I don't think it would matter much if you used a 1/8". There's enough metal around the slot as-is and it's just a way to get steam from one place to another. I was about to use a 1/8" end mill when I discovered the 3/32 hiding out in my tiny endmills box.

You can see the slots in this picture and get an idea how much space there is.




Also in the picture is the valve spools I just got done with (they are somewhat less gnawed-out-looking than the pic). That took four tries to get two decent ones-- When reading the instructions, when he says "put the unthreaded end in the chuck", he means "Stuff that end far into the chuck and don't cut on it, dummy!" ;D). They also get very fragile when drilled out-- no heavy cuts allowed.

I tapped the end #4-40 (there doesn't seem to be any text about how the two female threaded ends get connected on the eccentric strap, but I suspect I can work that out based on the pictures) and cross-drilled with a 1/16" end-mill. I had no spotters or centers that were going to sneak down that far next to the collet block I used to drill them and 1/16" is only a little over 1.5mm anyway.


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## steamer (Apr 27, 2009)

Looking good!

Mr. Lego appears to be deep in thought?  ;D

Dave


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## ozzie46 (Apr 27, 2009)

Thanks Shred, Looking good. 


 I have 4 Blocks ready to be bored at this time. I expect to make a lot of mistakes. :big: :big: :big:


 Ron


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## Blogwitch (Apr 27, 2009)

Shred,



> there doesn't seem to be any text about how the two female threaded ends get connected on the eccentric strap



Top of page 53 and bottom of page 54 shows it all.

A tiny bit of threaded rod.



Blogs


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## shred (Apr 28, 2009)

ozzie46  said:
			
		

> Thanks Shred, Looking good.
> 
> I have 4 Blocks ready to be bored at this time. I expect to make a lot of mistakes. :big: :big: :big:
> Ron


Those blocks have lots of places to mess up, but if you take it steady and recheck everything you should be good. Remember not to do the final valve spool bore until after the cross holes are all drilled. I reamed mine .249" (I have an O/U reamer set), then made a toolmakers reamer out of the drill rod I'd made the spools from to do the final hole sizing (as seen here but leaving a small flat on the end of the reamer-- no need to harden for one or two-time use in brass). 



			
				Blogwitch  said:
			
		

> Shred,
> 
> Top of page 53 and bottom of page 54 shows it all.
> 
> ...


Thanks.. I finally noticed that this morning.. that makes two errors in the plans I thought I found and didn't!


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## shred (May 2, 2009)

Making a quick run-by to check what I did on something earlier...

Here's the in-process eccentric straps to-date. I got a little more on them versus the plans. The first corner cut I did with the rounding bit to match the other flourishes, but that still looked too bulky, so I went for a little closer to the classic eccentric look and took some swoops out with a 3/8" ball end mill. I considered going a lot further and doing a nut-n-bolt style setup, but so far stopped here. Since I didn't pre-plan for this, I broke into the screw holes. No big deal for me, but if you care, you may want to be more careful when drilling them in the first place.




It took a while to bore the holes (I did that before the bling cuts when it was still easier to hang onto) since not only wasn't it a convenient drill size, but the eccentrics themselves weren't quite the same. Throw in a floppy boring head and it took a while of lapping with polish and hand work to get a good fit on both.

For the de-metricers, I used #2-56 for the strap bolts and 1/8" for the rod hole. A few more bits to crank out and we should be close to the first run.

Note on the plans the distance to the center of the eccentric strap is blurry and looks a little like 11.5. Obviously it's supposed to be 10.5 if the overall width is 21mm.


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## bearcar1 (May 2, 2009)

Looking good so far Shred, The suspense is killing us. I like the little bit of tasteful 'bling bling'. Rather Art Deco-ish. Nice touch.

BC1


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## shred (May 3, 2009)

Got the rest of the valve string done. With a little plumbing (and reassembly) this thing would run, albeit without the control block. Maybe I can get on that after a mandatory yard-work break  :-\




I also made the link pins according to the plans this time. It's the first time I've tried this method and it works well. I left some length on the off side to visually balance the nut, but it could go all the way flush if desired. If you don't have a copy of the plans handy, the pin is a short length of 1/8" rod with a #2-56 thread on one end. The joint sections are all reamed 1/8" except for one side of the outer joint, which is drilled to a #2 clearance. So, assemble the pieces, stick the threaded pin all the way through and bolt it on. No worries about the nut tightening and locking up the joint since all it does is hold the pin in place. The rest of the joint gets to run on a nice piece of smooth finished 1/8" rod.




De-metric notes: valve packing gland- 1/4-28 thread. Drilled to match spool valve stems. Attached to the block with, as usual, #2-56. A slightly loose fit on the gland attachment screw through-holes may help with fitting up later. Joint pins 1/8" with #2-56 thread on one end. The pack nut was made from 1/4" hex rod which will feel a tad small if your valve stems are large.

The eagle-eyed will notice I've loctited (using the uber-strong 'sleeve retainer') the top of the eccentric strap on versus silver soldering it for the time being until I decide if I want to bling it further.


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## Blogwitch (May 3, 2009)

> With a little plumbing (and reassembly) this thing would run, albeit without the control block



Go for it Shred, give yourself a Cheshire cat grin. It is just what you need at this stage to keep the momentum going after doing such great work.


[ame]http://www.youtube.com/watch?v=I8UCWr_BeqE[/ame]


Blogs


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## ozzie46 (May 3, 2009)

Is it just me or did shreds pics go away?

 Ron


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## ozzie46 (May 4, 2009)

I can see the pics today, Why not yesterday??? scratch.gif scratch.gif scratch.gif scratch.gif scratch.gif scratch.gif

 Ron


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## shred (May 4, 2009)

The pics are hosted on my desktop server, which is on a poor-quality DSL link, so if the pictures go away, wait about 10 minutes for the link to reestablish itself and they should return. 

I did get it all reassembled last night (about fifty #2-56 screws ), but it still won't turn over completely on air (it's close) so I need to go revisit the friction points and timing tonight.


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## shred (May 4, 2009)

Not quite running, but here's where it is. The control block and plumbing up top is yet to be done.


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## shred (May 6, 2009)

It Runs!

After a couple evenings dinking with it, tearing it down, smoothing it out, putting it back together, timing it and re-timing it, running it in on a drill and having it almost-run on air, I finally got it sorted.

It's kinda funny now.. I'd just torn it all the way down and polished and tweaked a little more on the crossheads and reassembled it and timed it yet again and as usual, it kicked when turned over by hand, but didn't run. This was getting tedious... 

Then I went through re-timing it one more time (the built-up bolted together crankshaft is a bit of a nuisance when trying to get the thing going-- as soon as something binds, it throws the crank out and you have to fuss around re-setting the crank and the timing). 

After I set one end eccentric, I moved down to the other end to set it's eccentric and for some reason hit the air valve on the way before I set it. PHIPHIPHIP.. WAITTAMINUTE! it turned over! Crap, I've been setting the eccentrics wrong. :'(  No wonder it didn't want to run.

Here's the trick-- set each eccentric with it's corresponding crank webs on the same side of the engine as the other one is set. Seems so simple now, but for some reason I had it in my head that they needed to be set opposite from each other (the instructions, as usual, are correct, it was me that mis-remembered them on the way from the PC to the shop)

First Run Video

It's running a temporary manifold for testing and about 40 PSI as I've yet to make the control block. It's leaking air like a sieve as there's no packing, piston rings or sealant anywhere, but it runs along nicely. On 80 PSI it buzzes like mad.


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## kvom (May 6, 2009)

Super! :bow:


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## Blogwitch (May 6, 2009)

Nice one Shred,

With the cheesy grin, and your confidence boosted, you can now carry on and bling to your hearts content.

It does pay sometimes to read the instructions.

You are the first one to build and show it running on the web (other than myself), you can be very proud of yourself.


Blogs


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## Maryak (May 6, 2009)

shred  said:
			
		

> It Runs!



Great stuff Shred - congratulations :bow:

Best Regards
Bob


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## shred (May 10, 2009)

Had some relatives in town and fired the CNC Taig up for the first time in ages to do a little project for work, so not much progress... just the steam control block made and blinged a little.





I find it much easier to do edge-y things like this by setting the corner rounder (or chamfer or whatever) running along the fixed jaw of the vise and flip the part around as needed to catch all the edges. I think I got that tip from 'Machine Shop Trade Secrets". Here I've already done one side and flipped the part to cut the other. The downside is you can't watch the cut, but it's more than made up for in convenience.

These are with the rounding bit (I think it's 1/8" round, but it's not written on the obtained-surplus bit) centered on the jaw and 2.25mm down in Z, though sometimes in my limited corner-rounding experience I've moved the Y a bit to get the effect right (on this engine I've been 'abusing' the corner rounders by making them make a router-like cut with flats leading to a quarter-round section, no doubt with a proper router-bit name like 'Roman Ogive with a Half Gainer' that I'm conveniently unaware of). Experimenting on some scrap first is recommended.


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## shred (May 21, 2009)

No real engine progress lately.. I decided (on John's advice) I wanted bent tubing and have been sidetracked building Bogs' favorite tubing bender (and a whole lot of work-related late night conference calls to Asia that cut into my evening shop time. )






Pretty straightforward, though I simplified it a little and skipped a lot of the draw-filing.  Whoever "Torus" is, he really likes his draw-filing (note there are a few dimensions missing and a couple incorrect metric->imperial conversions on the drawings-- if you build this one pay careful attention )

The most interesting part was making the rolls. I used a method of cutting half-round grooves taken from Frank Ford's FRETS pages-- it's a bit of a hack, but worked.

In summary, load a round bit of the appropriate diameter into a QCTP holder and using the QC height adjustment as the 'infeed', run the lathe in reverse (non-threaded chuck required) and cut on the bottom. A little rake helps but there's still no clearance, so cutting isn't great, but it worked ok-- cut a little, move it up, cut a little more until you get the depth you want. 






 Short length of hardened drill rod turned to size used as cutting bit





 Sharpening and putting a bit of rake into the bit.. QC holder is upside down in this pic





 (lathe is in reverse)

Making them with a RT and mill would probably be better... I'll try that when I get my RT going vertically.


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## shred (May 23, 2009)

Used the new bender to crank out some plumbing for a bent-pipe manifold. Here it is mocked up-- nothing soldered in yet, the brass screws are just to make sure the pipes won't block the cross hole.  Cutting little bits of bent pipe identically is sort of irritating... anybody know any good tricks for that? These pipes aren't quite identical, but I'm suspecting that silver-soldering and subsequent fitting will get them bent up some more anyway.


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## kvom (May 23, 2009)

Interesting look with the bent tube and flat flanges. More things to think about.  8)


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## rickharris (May 23, 2009)

http://nextday.diy.com/app/jsp/product/productPage.jsp?productId=21946 Shows a pipe cutter many DIY stores will have in the plumbing section - I have one that woks very well.


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## shred (May 23, 2009)

kvom said:
			
		

> Interesting look with the bent tube and flat flanges. More things to think about.


Bogs says the engine looks better with curvy pipe on it and I agree. I've not fallen in love with this particular bend set, so may try a few more options before soldering it all up. 



			
				rickharris  said:
			
		

> http://nextday.diy.com/app/jsp/product/productPage.jsp?productId=21946 Shows a pipe cutter many DIY stores will have in the plumbing section - I have one that woks very well.


That one works well on thin-wall tube? The similar cheapy one I have is pretty useless for annealed thin-wall, just bending the heck out of the tube before cutting anything. I'll have to see if better quality ones work better or if an insert might help. Actually cutting the tube is only half the battle though-- getting the lengths all trimmed up identically gets tedious as well (I've been bending a longer bit of tubing, then trim to length). I'm now kicking around the idea of making a specialized clamp which might work.


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## rickharris (May 23, 2009)

The one I linkes to is made to cut small diameter small bore heating pipe and I have cut thin brass tube down to 3 mm easily and cleanly - it makes a progressive cut - You tighten it up as you turn it round the pipe.


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## Blogwitch (May 23, 2009)

Shred,

Try this method.


Blogs


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## Maryak (May 23, 2009)

Good One Blogs :bow: :bow: :bow:

Best Regards
Bob


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## shred (May 24, 2009)

Simple and works better than holding them next to each other..  Thanks 

The drilled-pliers (another classic Bogs' tip) worked great to hold the bent bits up against my mini belt sander for final length adjustment.


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## mklotz (May 24, 2009)

Bogs is right on about cutting small or thin copper/brass tube. A cutoff disk in a Dremel is the stress-free way to do it and, done carefully, produces a finished edge that needs not much more than a tiny bit of deburring.

You'll get much better results doing this job and many others if you build an accessory table for your Dremel to provide the necessary alignment. I detailed such a table in an earlier post...

http://www.homemodelenginemachinist.com/index.php?topic=414.0


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## shred (May 24, 2009)

mklotz  said:
			
		

> Bogs is right on about cutting small or thin copper/brass tube. A cutoff disk in a Dremel is the stress-free way to do it and, done carefully, produces a finished edge that needs not much more than a tiny bit of deburring.
> 
> You'll get much better results doing this job and many others if you build an accessory table for your Dremel to provide the necessary alignment. I detailed such a table in an earlier post...
> 
> http://www.homemodelenginemachinist.com/index.php?topic=414.0


Funny.. I have that page open on a browser tab right now.. left over from deciding yesterday if I wanted to go make one right away or wait until this project is over.. With only 8 tubing cuts and a previous tool-making digression most of last week, laziness won out, but it's in the 'things to make' box now.


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## mklotz (May 25, 2009)

It's one of those "baseball diamond" fixtures - make it and the ideas for using it will come.

To that end, keep flexibility in mind while designing it and don't be too quick to cut off what looks like excess material unless it's really in your way - there's no telling what you may invent to hang on it down the line.

The paper thin, about 1" diameter, cutoff disks Dremel sells work really well but they're fragile as hell. The slightest twist while using and they fracture. Dremel now sells some reinforced (~ 2" diameter) disks that are much sturdier. In addition, they alleviate the interference problem when cutting long stock.

Also, I use mine all the time for sizing small machine screws. (It's more economical to buy bulk quantities of 1/2" length and cut them down to needed size.) There are endless possibilities for screw holders to be used in conjunction with the cutoff guide pictured in my writeup.

Be sure to show us your version when you get it built. I for one will be anxious to steal any clever details you might include in your design.


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## shred (Jun 6, 2009)

Alas shop-time is becoming scarce these days, with competition season heating up and the shop heating up (95'F/35'C today ). We do have a very good (and cheap) wholesale bolt-and-screw store here that's about made me give up on cutting down machine screws unless I really need one now or really need an off-size. The Dremel-table is still on-plan for everything else it's good for.

Anyway for the past few weeks I've been faffing around soldering up the piping and control block.

I thought I would try tumbling the fire scale off after pickling in a vibratory tumbler.. that took forever and a day (well, several days), then I saw one of the joints wasn't complete and had to go re-solder it.. Not wanting to tumble again, it went into the microblaster and five minutes later, it was clean and while rather matte than shiny, plenty good enough. The bonus of being able to blast off some errant silver solder easily was handy too (if you bling-corner the block like I did, watch out-- some solder ran off down the bling-channels instead of going up the proper spouts and would have been very difficult to remove without the blaster.)

Here's a staged photo in the hearth (post-blasted block, not bolted to the engine, etc):




The burnt-looking torn piece under the block is a little scrap of 1/8" fiber paper. Sometimes called 'fiberfrax', it's a heat-resistant ceramic paper material with a binder that burns off and smells like burnt sugar. Available for a few dollars a square foot at glass shops catering to the glass fusing crowd (they call it 'fiber paper' of all things). I use it for molten glass and underneath torch work and it works well-- not even a smudge or flux drippings on the underlying block.

The bit of hex rod over on the side was used previously to prop the bent tubes on for soldering to the flanges; Since I bent then soldered the tube, the hex gave the off-end a place to sit still in proper orientation to the flange which was flat on the hearth.


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## Blogwitch (Jun 7, 2009)

Roy,

You have done a great job on that silver soldering job, very professional indeed.

A thin sheet of almost any metal between the parts would do as a heat shield, as long as it is not touching the valve block.

The way to make the parts hold together by themselves is to very gently squeeze the end of the copper tubes to ever so slightly deform them. Then they should hold in their holes in the right position while you continue with the dastardly deed of soldering them up.

I must admit, they do look a lot better with the bent tubing, but if you remember it was designed for people who didn't own such a thing as a tubing bender.


Blogs


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## shred (Jun 7, 2009)

Thanks Blogs. I did blast off some extra SS to clean it up 

I used the fiber paper because I have it handy and resists temperatures over 2000'F, but thin metal would be good for this operation as well.

I squeezed the tube ends a little, but the flanges wanted to creep up the tubes and rotate when heated since I probably didn't squeeze them enough. Setting one end on a conveniently sized bit of hex was the quick solution.

Hopefully I'll get time to finish up the control valve before too much longer.


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## RobWilson (Jun 7, 2009)

Very Fine Work shred , great post :bow: :bow:


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## shred (Jun 25, 2009)

At last, a little more shop time.. I got a start on the last bits for the control block. Lapping the valve I think was a lot more effort than it should have been.. I started with a 'just barely won't fit' and went from there. In the process some of the copper piping on the block got a little bent but nothing that can't be tweaked back into place later. Were I to do it again I might consider lapping before soldering on the plumbing to the control block-- less to get in the way.





The O-ring I decided on was one with just under a 5/32" ID-- very close to 4mm and by using the formulas in Kozo's New Shay book, a 5/32" shaft should be just about right for a 10% squeeze.


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## shred (Jun 26, 2009)

Got the control valve spool fitted and cut. When Bogs says it's going to take a while to get the spool right, he really means it. That's pretty much all I did this evening. I found my ER collet chuck in the lathe to be really handy for this step, both for trimming the spool end and holding it when assembled to test-turn it and work it in. 

Sorry, no pictures  The piping is still askew from the beating it's taken the past few days. A quick anneal and straighten should sort it out.


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## Blogwitch (Jun 26, 2009)

Roy,

By this time, you are reaching the end of the build, not only should you end up with a well running engine, but you will have a lot more arrows in your quiver.

It looks to be a monstrous engine to build, but is rather easy if you follow the instructions. You should now be able to look at much more complicated builds without the fear maybe you once had.

Very well done indeed, you should be proud of yourself.


Blogs


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## shred (Jun 27, 2009)

Thanks John.. it's been fun, educational, and a great way to get the hang of my new mill.

Here's where we are today-- made an arabesque lubricator to go with the general theme, though I think the top and bottom pips may be a little out of character.

With that, all the parts are made! I'll need to get some more 5/32" tubing to complete the exhaust if I ever want to run it on steam (why do I always run out of such things right after the stores closed on Saturday, leaving me to suffer through to Monday ). Steam may be a while yet anyway, so I'll probably take another spare flange (make extras, John says! ) and make an air intake with some sort of in-line drip oiler.

Now it mostly needs a whole lot of elbow grease, sanding and polishing..


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## Blogwitch (Jun 28, 2009)

Wonderful Roy. You have turned a generally available engine into one that you can call unique, purely because you have put your own personal artistic stamp on it.

One (or a few) good piece(s) at a time, and you got to where you needed to be.

You can still drip feed on air with the steam luber fitted, it won't cause you any problems, but of course, it won't work as it should without steam either.

Leave the luber as it is, it came from your imagination at a certain point in the build, so it must be right, no matter what you think of it now.

Blogs


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## SBWHART (Jun 28, 2009)

That's a real nice looking engine Roy.

Been following the build with interest, I like the arabesque finishing touches.

Will you show a video of it running ?.

Have fun

Stew


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## RobWilson (Jun 28, 2009)

Hi shred 
That's a wonderfull engine,i like the touches you have added to it, great work :bow: :bow: :bow:
Regards Rob


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## shred (Jul 12, 2009)

Finally got some video--

[ame]http://www.youtube.com/watch?v=Se-6AZFyH70[/ame]


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## vlmarshall (Jul 12, 2009)

Beautiful work.


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## rake60 (Jul 12, 2009)

Beautiful build shred! Thm:

Rick


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## joe d (Jul 12, 2009)

Shred

Way to go! All the work bending tubing was worth it, looks great!

Cheers, Joe


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## zeeprogrammer (Jul 12, 2009)

Wonderful stuff.
Yet more inspiration.
Thanks.


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## steamer (Jul 12, 2009)

Awesome Build Shred!

Dave


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## ksouers (Jul 12, 2009)

That's really cool, Shred! Runs really great.
I can't believe that's only 5 PSI.

Congratulations!


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## ozzie46 (Jul 12, 2009)

Great looking engine Shred, Where did you get your 5/32 copper tubing? 

 I have not been able to locate any locally yet. Not thru looking yet either.

 Drilled my steam chests for the 1/4 valve and goofed up and reamed them before I drilled the rest of the holes. I hope they will clean up by running the reamer thru again after the holes are drilled.

  Ron


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## cfellows (Jul 12, 2009)

Very nice work, Shred.

Chuck


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## shred (Jul 12, 2009)

ozzie46  said:
			
		

> Great looking engine Shred, Where did you get your 5/32 copper tubing?
> 
> I have not been able to locate any locally yet. Not thru looking yet either.
> 
> ...


The 5/32" tubing was in one of those K&S Metal racks at a local hobby store (I found it in the 1/8" tubing slot jumbled with the 1/8". Lazy stockers, it pays to check them all). I seem to remember reaming those holes before drilling and tapping too. At least I vaguely remember something of the sort, and in any case I had to clean up those threads with the tap again after polishing and ran the reamer through hand-held and hand-turned one more time.

ksours-- I was surprised how low pressure it would run (so much so I videotaped the regulator pressure gauge on one run). O-ringing the pistons seemed to help a lot (the noise in the video is my compressor and the air leak on that regulator, not the engine)

[ame]http://www.youtube.com/watch?v=GYmAee9Vmnk[/ame]


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## shred (Jul 12, 2009)

Here's a couple more beauty shots after I hosed off most of the oil and grime: 











http://www.shred2.net/~shred/gallery14/albums/album22/CIMG9813.sized.jpg


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## Blogwitch (Jul 13, 2009)

That is a rel real credit to you Roy.

You have persevered and made a totally unique engine, even though it was from 'plans', there will never be one exactly the same as yours.

Very well done indeed. It has been a pleasure and joy watching your journey.


For those that are making small engines, and do make mistakes, do not despair.

I am just doing a small article on another site about the rescue of a very badly built engine (not by me), and if you are fairly competant at silver soldering, shows just how easy you can bring something back from the dead. It could save you having to remake a very complicated part.

http://madmodder.net/index.php?topic=1370.0

Blogs.


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## Maryak (Jul 13, 2009)

Shred,

A unique and lovely engine. :bow: :bow:

Best Regards
Bob


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## arnoldb (Jul 13, 2009)

Very nice little engine Shred - Well Done !!

Regards, Arnold


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## kustomkb (Jul 13, 2009)

Looks and runs fantastic!

great job.

Kevin.


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## putputman (Jul 13, 2009)

Nice running engine and some real neat finishing touches to it.

Great job, Shred


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## shred (Jul 14, 2009)

Here's one for Carl.  : Most of the time when we mis-make a part it gets flung into a dark corner of the shop or straight into scrap bin, but this time I put most (there's a fair bit more malformed bits of copper tube flung somewhere) of them back into the engine project bin, so, when cleaning out the bin, I pulled out the unused, defective, off-size, temporary, and just plain ugly parts-that-didn't-make-the-final-cut. "Always make extras.." The Bogster says...  Wise advice.


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## zeeprogrammer (Jul 14, 2009)

shred  said:
			
		

> Here's one for Carl.
> 
> "Always make extras.." The Bogster says...



Hey thanks Shred. :big:

Until one can make 'good' parts...one must be proud of the 'less than good' parts. After all...there are many who make 'no parts'.

My only question...'Always make extras..'...of what? Nah. Don't answer that. Doesn't matter.


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## Blogwitch (Jul 14, 2009)

> My only question...'Always make extras..'...of what? Nah. Don't answer that. Doesn't matter.



Everything matters if you don't understand it.

If say you needed to make six identical parts for an engine, and each part needed a few operations to make it. Then it is always preferable to make one or two extras while you have the machine set up to do it, rather than bugger one up a little further down the line, after they are finished, and having to go back and redo all the setups just to make another one.
As long as the parts being made aren't going to break the bank in material costs, then it is much better to have to throw a few machined parts into the recycle box, rather than trying to go back and match up a new one if you do make a mistake later in the build.

Blogs


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## shred (Jul 14, 2009)

zeeprogrammer  said:
			
		

> Hey thanks Shred. :big:
> 
> Until one can make 'good' parts...one must be proud of the 'less than good' parts. After all...there are many who make 'no parts'.
> 
> My only question...'Always make extras..'...of what? Nah. Don't answer that. Doesn't matter.


As you get better, your standards get better, but I bet you ask any modelmaker and they can point out a screwup on the most perfect-looking engine they've made. 

Like Bogs says, extras are good for multiple parts. If it's a one-off, there's not generally much point making an extra. For things like the tubing flanges, I could have used a couple more of them; not because the first 6 were bad, but to make additional intake and exhaust pipework. If I'd had an extra crank web, I could have saved a bunch of dinking around trying to save one when the drill pulled through on it and/or ditched the one with the ugly saw cut (nearly impossible to see, but it's there). Fiddly things like packing glands you could pick the best 2 out of 3 instead of making do with only two.... and so on. I like trying to 'save' parts that have mistakes in them, but at some point it's just easier to make a new one, doubly so if you've got a partly-made spare on hand.


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## vlmarshall (Jul 14, 2009)

Also, when you kill one of your extras, hang onto it. Just mark it as a "setup piece" and do the first operation of each following step on that part first. That way you're not using up an extra with every mistake.

It's far easier to run an extra part or two, starting from step one, than to ruin a part at the last step and need to go back through every setup you've used, to get the replacement part caught up.


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## GailInNM (Jul 15, 2009)

For many years I went to various model engineering shows. At most shows there are "Do not Touch" signs everywhere. I always took so of my extra parts with me so people could pick them up and play with them. Remember, to the non machinist or novice who is just thinking about building an engine, even simple parts are "magic" to them. It does not matter if a crank journal is 0.005 under size to them. It can't be seen with the naked eye, so to them it is perfect. 

It is amazing what the simple act of holding a part can do to the mind of a ten or twelve year old youngster. And it is even worse for a thirty or forty year old youngster. I kept the parts in a bin near the front of the display with a sign encouraging them to play with them.  Sometimes I would give away a few parts to people who asked the right questions. For me this was a big part of going to shows. 

Gail in NM,USA


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## zeeprogrammer (Jul 15, 2009)

My question 'Why make extra parts' was meant as a joke but apparently was a poor one that took the topic off thread a bit. I apologize for that.

On the other hand, it resulted in some very handy tips and excellent comments.

In particular, Gail's comments. Some of my first practice pieces (small turned cylinders) sit on my desk at work. When people come by my desk...they can't help themselves...they pick them up and start asking questions.


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