AOG's version of Elmer's No 50 "The Educational"

[AOG]

I have recovered some more pictures from my camera. The next part to be made was the camshaft drive rod. I turned down a piece of square stock to dimension.



Then it was over to the mill where I drilled a hole and Locktited the drive pin into the hole.



The cam shaft itself was built up. I started with the driven end and drilled and Locktited in the shaft.



After the Locktite had cured I cross drilled the driven end to take the drive rod.



I was going to do the cam next but I was missing the required material so I moved onto the crankshaft. I started by marking out and drilling the blank.



Then the angles were milled on both sides.



Then it was over to the rotary table where the ends were rounded over.



Next the crank was drilled and tapped for. A setscrew.



The crank pin was pressed in and match drilled to the existing collar.



With that done I made the required crankshaft bearings but I couldn't find any pictures of that process. After that, I tried to see I could clean up the flywheel casting on my mill and made a complete hash of the job. I had made the necessary repairs and was waiting for material for my cam and a new flywheel casting. With that I think I'm caught up to where I was before the outage.

Tony


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[AOG]

Here it is. The post that people have been waiting for (or so I'd like to imagine) it's time to make the cam. If ever there was a part on Elmer's engines that could use some CNC love it's this one... but since I don't do CNC I had to bust out my inner Chris from clickspring for this one. The first thing to be made was the template. Elmer recommends some 1/16 brass for the template but I didn't have any big enough for the job so I squared up a chunk of aluminum to make it from. I made three attempts to lay out the template per Elmer's instructions but I never could get it right. That's when I remembered something I had seen on clickspring. I drew up the part in fusion360 and printed out full size. Then I glued the blank onto the paper. When the glue was dried I cut away the excess paper and moved it to the mill. I picked up the center point of the hole and drilled it out.



I don't have a scroll saw so I used my jeweler's saw to cut away most of the waste stock.



I used the belt sander to get closer to the lines and then I finished by filing.. and more filing and (you get the picture) the end result was this template.



Next up was to make the cam itself. I made what turned out to be a fortuitous mistake. Elmer tells you to make the part from 1.5 inches of 3/4 diameter stock. I went dyslexic and ordered 1.5 inch diameter stock instead of 3/4. This turned out to be a good thing. Elmer wants you to offset the 3/4 stock in the four jaw before you turn the boss. With the larger stock I had enough room to make the part with the stock centered in the three jaw. I don't know about anyone else but if I can avoid the hassles of a four jaw I will. First I turned the part to the larger diameter.



Then I turned down the boss until I got a good fit on the template.



Then the center hole was drilled and reamed.



The part was moved to the mill while still attached to the parent stock. Then the outline of the template was traced onto the stock. Next I milled away most of the excess stock.



The part was returned to the lathe and parted off. Then it was flipped and the back face cleaned up.



Next the shape was cleaned up on the belt sander and finished out by filing. After that the hole for the grub screw was drilled and tapped.



That leaves us with the final cam.



That leaves just the flywheel left. Till next time.

Tony



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[b.lindsey]

Great Tony and not as bad as you had imagined I am betting. As to the 4 jaw chuck, it can be your friend in many situations, don't be afraid to give it a try and I think you will find it very useful.

Bill

[AOG]

Thanks Bill, my hand work and my soldering are the two biggest things I need to work on in this hobby. This build sure gave the former a workout. As to the four jaw, I used to despise using it (and my face plate) because they took so long to set up. My set up skills have improved dramatically to the point that dialing in a four jaw is nearly as fast as a scroll chuck but I still don't enjoy the process. If I can avoid it I will.

Tony

[Flyboy Jim]

The cam looks good Tony.

I concur with Bill about a 4 jaw chuck. It's really useful and is easy set up since I made a fixture to mount a dedicated dial indicator on the back part of the cross slide of my lathe.

Jim

PS: I'm still on the same page as you when it comes to soldering. I just need to take the time to develop the skill.

[AOG]

Time to finish out the machining on this project. There is one part left, the flywheel. After my last debacle I decided to do this one on the lathe. Useing my three jaw and a bump tool to get it running relatively true, I cleaned up the center boss on both sides of the casting.



Then the center was drilled and reamed.



Next it was time to clean up the rim. I initially tried to do it with the three jaw and then I tried turning it on a mandril. In both cases I got awful ringing and abysmal surface finish. In the end I had to break out my faceplate in order to get enough rigidity to get a decent surface finish. Since the center hole was reamed out the part wasn't to bad to get dialed in using the live center.



With that completed I took the flywheel to the mill and drilled for a setscrew.



Here is the final family shot.



Time to polish, paint and fit it together. Hopefully next time you see it will be running in the showcase.

Tony


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[Don1966]

Nice work Tony and some great photos. Still with you.......

Don

[Mike Bondarczuk]

Tony,

Very nice family shot and looking forward to seeing it finally painted and assembled and then the video of the running engine.

Great pictures and detailed write-up and I just have the crank, cam and flywheel to make and will be ready to assemble and tune mine for a video so a couple of weeks behind perhaps.

What colour are you thinking off and my inclination for mine is to go with a red colour as near to the Dykem red as possible for the aluminium and steel parts and the brass will be left as brass.

Mike

[mklotz]

That's a big flywheel to be secured with only a setscrew.  I know the engine is low speed but, with a slightly jerky start, you run the risk of the crankshaft turning inside the flywheel.  If that happens you'll have a tough time getting the flywheel off the scarred crankshaft.

At least put a flat on the crankshaft for the setscrew to bear; I notice the plans don't call for one.

[AOG]

Marv, I normally file a flat on my crankshafts but I don't do it until assembly. I will put the flywheel where I want it and then crank down on the setscrew. Then I pull the flywheel off and file a flat where the dimple is. Mike, since I used a flywheel casting I plan on painting it red. I will then lightly polish the aluminum and brass. Then I'll Nitre blue the steel parts.

Tony

[AOG]

Today is one of those days. I've painted the flywheel and polished all of the aluminum. I was into that final fit and fettle stage. I went to mount the flywheel and it's .050 to big.  . I am going to have to turn it down to fit the frame. I should have checked before I painted the thing  . So much for finishing this weekend.

Tony

[b.lindsey]

Tony, you could always shim under the pedestals, or cut a recess in the base for flywheel clearance. Just a couple of options to consider.

Bill

[AOG]

I experimented with shiming but I didn't like the look. Elmer's original design had a recess in the base. It bothered my sense of symatry so I raised the pedestals instead. When I switched to a cast flywheel I forgot to annotate the dimension change on the flywheel diameter. In any case I already turned the flywheel and primed it. Hopefully I can get color on it before it gets dark.

Tony

[zeeprogrammer]

Looking forward to seeing the cam work! Details please. 

[Mike Bondarczuk]

Zee,

I found that the cam work was actually relatively easy, and hope that Tony agrees, as I used his idea of an oversize stock piece which meant that I could work with a three jaw initially and then switch to my 5C collets for holding and not have to worry about offsets.

I firstly turned down my stock to a 13/16" diameter for the 3/8" thickness and then sliced of just oversize at a few thou to leave room for clean up.

Placed the complete piece into a 13/16" 5C collet and turned down the non-cam side to 5/16" and then changed it over to a 5/16" 5C collet so that I could work on the cam face.

Painted with face with Dykem and then spotted the centre. Removed the work and placed it into a 5/16" ER32 collet in a square holder and with a compass marked out the 13/32" radius arc and then where it intersected the edge of the work marked out the two 5/8" radius arcs and finally the 7/32" radius bottom arc which gave me all of the lay lines for the cam.

Back to the lathe and drilled and reamed for the 1/8" centre hole and then off to the file for shaping, still using the ER32 square block holder to rigidly but safely hold the piece.

I am pretty sure that this was the same procedure which Tony used and I can say that it was not difficult at all, and when I post the final video I will show the cam in detail.

Just waiting for the stock for the flywheel and I am changing it to be 1/2" thick with 1/8" rebates each side though still 6" diameter, and Marvin has forwarded me the rotary table co-ordinates and that will be the subject of a separate build log on here hopefully next week.

Mike