I need to have an HS40 crankshaft cut down from 1” to 3/4” with the proper key slot of course. I’m in no hurry and the engine has not been disassembled as yet. If a member would like to take this on at their leisure please PM me. I’m in no hurry but I’d like to begin the process of modifying this snowblower engine for use on my cat 400ts. Thank You in advance.
Crankshaft modification
- Thread starter Ginz61
- Start date
I just looked at it closer earlier today and it looks like it’s drilled but not tapped. It was gunked up in there and looked like threads. I think the warranty ran out on my orbital ocular orbs. 60+ years so I can’t complain. Also I found a member here that will machine the crankshaft down for me and tap it too I’m sure.This site rocks.
If that member wants to maybe cut a couple HS shafts down at the same time I have at least one that needs to be turned down to ball bearing specs, probably 2 (donor engine just came in with and have not yet checked journal condition). I have extra Ball bearing crank that can be sent along to copy and Tecumseh crankshaft spec sheets with measurements as well
I tapped one years ago that had an unthreaded pilot hole. It wasn't that difficult. The core of most cranks are malleable and thread pretty easy. Keep it straight and dont rush it, use plenty of cutting oil, and clear your tap and hole often. An air nozzle works best but flooding the cavity with spray penetrant will do if air is not available. The turning down or grinding down would be ideal, and would best be achieved by someone equipped for such for concentricity and circularity sake to prevent beating your case to death. This stuffs getting hard to find in usable condition. Well good luck with it.
I believe I could handle the tapping of it but have found a highly qualified site member willing to help me out so there is no need for me to attempt it. Parts are getting rarer and harder to find for reasonable prices and modifying my original crankshaft is imho my best option. Thank you for your well wishes and I’ll let you and the membership know the outcome.
And one last side note to keep in mind if i might, by the time the crank is cut down and put on size you may not have much surface treatment left afterwards. Durability after which might be a concern (flexing) under load. Most fractional h.p. cranks have a hardness depth anywhere from .040" to .120" or there about so might be close. Might want to research you model to find some more exacting figures. Hope that helps with some more insight for you and things to conscider.