The Craftmans Shop > Model Engineering
Side Valve i.c. engine from Bar stock
lordedmond:
The pin is not to fix but to locate it the glue that fixes the cam, the position I mentioned for the pin is the non working area and will not cause any problems.
With this method you can harden the cams right out and then put them on the shaft , pin hole drilled before hardening as you know
Stuart
Brian Rupnow:
Okay--Experiment completed. I had a bit of left over 1/2" drill rod. It cuts very easily with a file. I flame hardened and quenched one end, put it in the lathe to hold it, and tried to cut it with a file. Couldn't cut it at all. Harder than the devil's horn!!! I set it up in a vice and silver soldered a small bit of 3/16 mild steel shaft to the end of it, let it air cool, and again set it up in the lathe. The file now once again cuts the drill rod very easily. The heat of silver soldering "unhardens" the hardened drill rod. Looks like I will be using Stuart's suggested method.---Something worth remembering!!!
Brian Rupnow:
AAARRRRGGHHHHH!!!!!!!!!!---Giant headslap for me!!! I cross drilled the cams, hardened the cams, cross drilled the cold rolled camshafts, made up .093" cold rolled cross pins----and trial fitted everything. Was being REALLY careful with the cams. Slathered everything with Loctite, dropped the cam into place, aligned the cross drilled holes, and as I pushed the .093 pin into place by hand, encountered some resistance. Took it out to the anvil and CAREFULLY tapped the pin all the way thru.--And then---just as I thought I had won---I heard a little "crack"!!! OH POOP!!!!!
Brian Rupnow:
They were supposed to BOTH look like the one on the left----Honest!!! The cross pin is mild steel and will get filed down until the surface is an exact match for the hardened cam surface. And everything is coated with #638 Loctite.
Brian Rupnow:
I have been so overwhelmed with "busy" in the rest of my life, that I haven't had time to devote to this engine lately. I did manage to steal two hours yesterday evening to remake and harden the cam which was broken and assemble the cams, camshaft, gears, and tappets and tappet guide. This engine is getting very close to being a runner. During the rush leading up to having the top end of the engine finished, I forgot to lap the valves into their seats. Fortunately, I can easily access the valve stems to grip them with a finger chuck when the cylinder is removed from the engine, so that shouldn't be a problem. I am very pleased at how well the gear/cam/tappet train seems to work, so have attached a short video of them in operation.
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