That's exactly what I was thinking about Gail. That will probably be a whole heck of a lot easier than trying to find the BeCu in small-ish quantities. Those Hall effect sensors are looking better all of the time. 
BC1
Jim
BC1
Jim
The Geneva .... My first Hit and Miss Engine
- Thread starter bearcar1
- Start date
Help Support Home Model Engine Machinist Forum:
Hello Arnold, glad to know that you are keeping an eye on me ;D and yes, red wine. Of course white will also do in a bind, but after that it is what's in the cleaning products cabinet. Rof}
Thanks Doc', I'm glad that's over with. Been tinkering with the cam blanks and using what appears to be a rather neat set up for turning the part up on the lathe. Time will tell.
BC1
Jim
Thanks Doc', I'm glad that's over with. Been tinkering with the cam blanks and using what appears to be a rather neat set up for turning the part up on the lathe. Time will tell.
BC1
Jim
Things have been quiet here for several days but I did manage to get some practice in turning single lobe cams on the lathe. 8) I started out by turning these three 'blanks'. Nothing fancy here, just some rather tough steel bar that I had in the drawer sized accordingly and parted off.
Then I proceeded to make up a simple jig that was nothing more than another piece of steel round that I had been using as a simple mandrel type fixture except I used the opposite end for this one. A hole was located, drilled and tapped 1/4-28, off center and a socket head cap screw was used to hold the blank(s) at the correct distance from the center axis of the lathe.
An application of layout dye helps tremendously in witnessing the arcs as they are being progressively cut. After mounting up the prepared blank, the cross slide was advanced to take small cuts until the blank measured .538" across the now 'small' diameter. Once this measurement was reached the compound was not touched again until the cam had been completely turned. Here, one can see what that initial cut appears like.
Then, the blank gets rotated about 3* and another cut was taken. I tried turning the blank CCW or into the cutter as well as CW or away from the cutter and found that by incrementing the blank CW, that it seemed to leave less prominent apexes that required filing down when finished but I am sure this was just a fluke on my part. In theory, the fewer degrees the blank is rotated each time the 'rounder' the final piece will be due to these overlaps becoming closer together. Anyway, this is what the part looks like after the second pass.
And then again after about the third or fourth pass. (I lost count ;D)
Here, I'm closing in on the final cut as the blue surface area is getting narrower with each series of cuts. My target width is .050" left uncut. When I was satisfied with everything, I used a small, 'dull' file to smooth out any of those apex ridges I was mentioning and lightly brushed the face with emery cloth to further smooth out the running surface of the cam.
These cams still require that a large flat be milled at an angle to assure that the ignition points fire off at the proper time (approximately 1* ATDC according to the drawings) but I am going to wait to do that until after I am further along in the build. The cam also gets a .031" hole drilled axially through the hub to facilitate a small pin that will ultimately be used to secure the cam to the large gear. Looking ahead, that should prove to be a real PIA as there is no way to hold the two parts together before the final coup d' gras as it were. scratch.gif :shrug:
This was the first time I had ever used this method of making a cam and found it to be relatively pain free and am hoping that I can utilize this experience gained in other future projects. I'm certain that there are formulas or programs out there that will/would calculate the required co-ordinates for making the holding fxtures to turn out specified profiles as the need arose.
So far..... so good.
BC1
Jim
Then I proceeded to make up a simple jig that was nothing more than another piece of steel round that I had been using as a simple mandrel type fixture except I used the opposite end for this one. A hole was located, drilled and tapped 1/4-28, off center and a socket head cap screw was used to hold the blank(s) at the correct distance from the center axis of the lathe.
An application of layout dye helps tremendously in witnessing the arcs as they are being progressively cut. After mounting up the prepared blank, the cross slide was advanced to take small cuts until the blank measured .538" across the now 'small' diameter. Once this measurement was reached the compound was not touched again until the cam had been completely turned. Here, one can see what that initial cut appears like.
Then, the blank gets rotated about 3* and another cut was taken. I tried turning the blank CCW or into the cutter as well as CW or away from the cutter and found that by incrementing the blank CW, that it seemed to leave less prominent apexes that required filing down when finished but I am sure this was just a fluke on my part. In theory, the fewer degrees the blank is rotated each time the 'rounder' the final piece will be due to these overlaps becoming closer together. Anyway, this is what the part looks like after the second pass.
And then again after about the third or fourth pass. (I lost count ;D)
Here, I'm closing in on the final cut as the blue surface area is getting narrower with each series of cuts. My target width is .050" left uncut. When I was satisfied with everything, I used a small, 'dull' file to smooth out any of those apex ridges I was mentioning and lightly brushed the face with emery cloth to further smooth out the running surface of the cam.
These cams still require that a large flat be milled at an angle to assure that the ignition points fire off at the proper time (approximately 1* ATDC according to the drawings) but I am going to wait to do that until after I am further along in the build. The cam also gets a .031" hole drilled axially through the hub to facilitate a small pin that will ultimately be used to secure the cam to the large gear. Looking ahead, that should prove to be a real PIA as there is no way to hold the two parts together before the final coup d' gras as it were. scratch.gif :shrug:
This was the first time I had ever used this method of making a cam and found it to be relatively pain free and am hoping that I can utilize this experience gained in other future projects. I'm certain that there are formulas or programs out there that will/would calculate the required co-ordinates for making the holding fxtures to turn out specified profiles as the need arose.
So far..... so good.
BC1
Jim
That's a neat way to make the cams, Jim, and you explained it well.
Just wondering, why three cams? One for points, one for exhaust, one for?
For drilling the hole to pin it to the gear, maybe use a shaft through them, hold them secure with
blue Loctite, drill, then warm them up to release the glue. The blue kind gets soft at pretty low temp,
and releases easily.
You made good progress!
Dean
Just wondering, why three cams? One for points, one for exhaust, one for?
For drilling the hole to pin it to the gear, maybe use a shaft through them, hold them secure with
blue Loctite, drill, then warm them up to release the glue. The blue kind gets soft at pretty low temp,
and releases easily.
You made good progress!
Dean
![DreamPlan Home Design and Landscaping Software Free for Windows [PC Download]](https://m.media-amazon.com/images/I/51kvZH2dVLL._SL500_.jpg)
Good morning Dean, I apologize to you and anyone else for the confusion of having cut three cams in this illustration. The engine itself only requires one cam to run, but the blanks themselves were such a simple turning job and I had a lot of time on my hands, so I figured that as long as I was "in the mood" it would be to my advantage to make multiples "just in case" : You know what I'm talkin' about. I had never made a cam using this method before and did not really know what to expect along the trail either, hence the extra insurance of having back-ups seemed like the prudent thing to do. ;D Thanks for the tips on holding the gear and the cam together, I had it in the back of my feeble little mind to use a drop of cyanoacrylate adhesive (basically the same thing). The trouble I envision is getting the timing set accurately before hand and the two pieces marked as such, before having to drill several holes in an attempt to preserve the settings. I'll cross that bridge when I get to it and am not going to worry a great deal about it at this time but it still is yet another one of those nagging problems that seem to accumulate during a trial period such as this build has been. Hey, thanks for staying tuned, at least I do not have to fret over not having company on this adventure :bow:
BC1
Jim
You know what I'm talkin' about. I had never made a cam using this method before and did not really know what to expect along the trail either, hence the extra insurance of having back-ups seemed like the prudent thing to do. ;D Thanks for the tips on holding the gear and the cam together, I had it in the back of my feeble little mind to use a drop of cyanoacrylate adhesive (basically the same thing). The trouble I envision is getting the timing set accurately before hand and the two pieces marked as such, before having to drill several holes in an attempt to preserve the settings. I'll cross that bridge when I get to it and am not going to worry a great deal about it at this time but it still is yet another one of those nagging problems that seem to accumulate during a trial period such as this build has been. Hey, thanks for staying tuned, at least I do not have to fret over not having company on this adventure :bow:BC1
Jim
bearcar1 said:make multiples "just in case" :
BC1
Jim
Yeaaah buddy. I know!
Good foresight. Bill is on the same boat, making extras when he did his rings for his B&S engine.
I have a cookie tin full of those "just in case" extras. They're my "warm 'n fuzzy" spares.
I think you're on the right road with using some kind of adhesive for drilling those things.
Dean
It has been a while since any updates have been posted and I apologize for that to one and all, however, having finally been able to take a short call for real work out of the hall, I do not feel too bad about it. All good things come to an end and I am once again 'idle' in my days so I figured I had better get something done and show it lest you fellows begin to think that I do not love you anymore : I wanted to do something that was relatively simple (yeah right, like ANYTHING is simple) and was torn between the regulator weights or the muffler and decided at the last minute on the later of the two. D. Kerzel's drawings show something similar to my end result but my "can't leave well enough alone" disease flared up again and it was off to the races. Beginning with a short piece of .750" brass round I faced both ends and drilled and reamed a .250" hole through the center. Moving the piece to the mill, I incorporated a cheap and dirty method of centering the part by using a short length of .250" rod in the spindle and merely clamped the vise to the table when the rod, being held in the spindle, was inserted in the central hole. The "X" axis was locked and I proceeded to mill a .187" slot to the required depth, after which I repeated the same steps, only this time locking down the "Y" axis and milled another slot creating a perfect cross. Next, I centered the piece once more but this time I used a protractor head set to 45* along the side of the vise and clamped it down. Keeping the "Y" axis locked, another slot was milled and the procedure repeated only this time with the vise clamped 45* in the opposite direction. (referenced from the table edge) When all of the dust had settled, this is what I wound up with.
I had considered cross drilling a series of through holes in the perimeter of the piece but opted instead to make this part in two pieces and am glad that I did for several reasons, the most important of which is the lack of a rotary table and I did not feel like fooling around with setting up the spin indexer, so cutting these slots that will ultimately end up being the final exhaust ports seemed the best route to go. Next up was the cover. Now I don't know about you, but I have always fancied those domed shaped mufflers on engines and I knew I had to attempt to replicate that look. Using .750" brass round I began to form the "friars hat" using a combination of files and a small cutter in the cross slide. The majority of this was done by eyeball and is really a matter of artistic appeal rather than any set dimensions and it took some time to get the desired results. Seen here after parting off I am cutting the inside of the dome with a ball nosed cutter.
Now I turned my attention back to the base piece and tack soldered a .250" piece of brass rod to it to be used as a mandrel in shaping the bottom portion. Again using files and the same cutter used for the top it was slow work sneaking up on a pleasing and symmetrical shape. What a PIA that was, "Do I take a little more off?" .... "How about a little flatter there" and so on and so forth. FINALLY, painfully, it was done, and I knew that I would still have to fine tune the whole thing once I had joined both pieces together.
Before I could proceed, I took a very fine square file and cleaned up any sharp corners and then very carefully tinned the tops of the "teeth" with soft solder. Putting this all aside for a few minutes, I was able to locate a small block of hard maple and after chucking it the lathe, I proceeded to bore and counter bore a hole that would *just* allow the muffler pieces to enter. This was a locating and holding fixture for when I sweat soldered the two parts together. One final once over with a file, I liberally fluxed the top, inserted into my jig, followed by the bottom and applied sufficient heat until I was satisfied the solder had melted and then allowed the part to cool down. I found that apparently the heating action swelled the wood slightly and I had one Hell of a time removing the piece and wound up using a wood chisel to split the block in order to free my prize. Once more onto a temporary mandrel and after some diligent file work, this is what I wound up with. Whew!
So far, so good.
BC1
Jim
I wanted to do something that was relatively simple (yeah right, like ANYTHING is simple) and was torn between the regulator weights or the muffler and decided at the last minute on the later of the two. D. Kerzel's drawings show something similar to my end result but my "can't leave well enough alone" disease flared up again and it was off to the races. Beginning with a short piece of .750" brass round I faced both ends and drilled and reamed a .250" hole through the center. Moving the piece to the mill, I incorporated a cheap and dirty method of centering the part by using a short length of .250" rod in the spindle and merely clamped the vise to the table when the rod, being held in the spindle, was inserted in the central hole. The "X" axis was locked and I proceeded to mill a .187" slot to the required depth, after which I repeated the same steps, only this time locking down the "Y" axis and milled another slot creating a perfect cross. Next, I centered the piece once more but this time I used a protractor head set to 45* along the side of the vise and clamped it down. Keeping the "Y" axis locked, another slot was milled and the procedure repeated only this time with the vise clamped 45* in the opposite direction. (referenced from the table edge) When all of the dust had settled, this is what I wound up with.
I had considered cross drilling a series of through holes in the perimeter of the piece but opted instead to make this part in two pieces and am glad that I did for several reasons, the most important of which is the lack of a rotary table and I did not feel like fooling around with setting up the spin indexer, so cutting these slots that will ultimately end up being the final exhaust ports seemed the best route to go. Next up was the cover. Now I don't know about you, but I have always fancied those domed shaped mufflers on engines and I knew I had to attempt to replicate that look. Using .750" brass round I began to form the "friars hat" using a combination of files and a small cutter in the cross slide. The majority of this was done by eyeball and is really a matter of artistic appeal rather than any set dimensions and it took some time to get the desired results. Seen here after parting off I am cutting the inside of the dome with a ball nosed cutter.
Now I turned my attention back to the base piece and tack soldered a .250" piece of brass rod to it to be used as a mandrel in shaping the bottom portion. Again using files and the same cutter used for the top it was slow work sneaking up on a pleasing and symmetrical shape. What a PIA that was, "Do I take a little more off?" .... "How about a little flatter there" and so on and so forth. FINALLY, painfully, it was done, and I knew that I would still have to fine tune the whole thing once I had joined both pieces together.
Before I could proceed, I took a very fine square file and cleaned up any sharp corners and then very carefully tinned the tops of the "teeth" with soft solder. Putting this all aside for a few minutes, I was able to locate a small block of hard maple and after chucking it the lathe, I proceeded to bore and counter bore a hole that would *just* allow the muffler pieces to enter. This was a locating and holding fixture for when I sweat soldered the two parts together. One final once over with a file, I liberally fluxed the top, inserted into my jig, followed by the bottom and applied sufficient heat until I was satisfied the solder had melted and then allowed the part to cool down. I found that apparently the heating action swelled the wood slightly and I had one Hell of a time removing the piece and wound up using a wood chisel to split the block in order to free my prize. Once more onto a temporary mandrel and after some diligent file work, this is what I wound up with. Whew!
So far, so good.
BC1
Jim
Thanks Dean, you know, I am *STILL* futzing with the shape of the bottom on that thing. Trying to get a match of the top isn't as easy at it may seem. I'll get it sooner or later but jeez louise, what a fiddly thing this is turning out to be. Not sure exactly what part I'll be attempting next but it's getting to the point where there aren't a whole lot of choices and my metal drawer is looking pretty bare. :'( Maybe I'll have to take up dumpster diving for some extra spending money :big:
BC1
Jim
BC1
Jim
LoL! :big: I'm sorry Dennis, I guess I'll have to work on my story telling skills some more. After going back and re-reading that last blurb, I can appreciate one getting lost until the very end and I was the one that wrote it. But hey, that's how modern suspense thrillers (or comic books) are written now. ;D I promise I'll try and do better the next time. :bow:
BC1
Jim
BC1
Jim
Good morning Bob and thank you. I *may* make an attempt at fabricating up another only this time drilling radial holes round the central rim instead of milling the slots. Then again, those holes would be pretty small and my eyes aren't what they used to be ya' know :big:
BC1
Jim
ya' know :big:BC1
Jim
- Joined
- Feb 25, 2008
- Messages
- 464
- Reaction score
- 7
Jim,
I wasn't complaining...I like the suspense! Besides, my ability to comprehend doesn't reflect on your ability to write. ;D Personally, I think the slots look great. I think the prototypes were built similarly.
Dennis
I wasn't complaining...I like the suspense! Besides, my ability to comprehend doesn't reflect on your ability to write. ;D Personally, I think the slots look great. I think the prototypes were built similarly.
Dennis
Oh I understand perfectly Denny, ;D Sometimes I get to thinking and typing at the same time and in the end the writing isn't what I was meaning but it was what I was thinking at the time. There. You see? That's what I was thinking.... oh Lord, please help me!!! :big:
Glad you understand and are staying along for the ride, I like the company.
BC1
Jim
Glad you understand and are staying along for the ride, I like the company.
BC1
Jim
zeeprogrammer
Well-Known Member
- Joined
- Mar 14, 2009
- Messages
- 3,362
- Reaction score
- 13
I'm really enjoying your thread. Partly because of your approach towards machining. I should be more like that.
Similar threads
