Re-sizing an output shaft for smaller seal

[Hermit Scott]

I have an old old 2QM20 that I am rebuilding. The transmission is very rare. Only 30 made by Yanmar. Then they switched to Hurth transmission.
So the output shaft was pitted and corroded. I put it in the lathe and turned it down until I got a smooth surface. The seal was a 50mmX30mm. I can buy a 50mmX28mm. The shaft is now 29.5 mm. I need to turn it down a bit more.
While I was turning it I noticed that the area where the seal contacted was hardened. It is only case hardened so I may have cut away most of the hard area. Does this have to be a hardened surface? Or can I get it to size polish it up and start assembling?

 

[woodster]

I have an old old 2QM20 that I am rebuilding. The transmission is very rare. Only 30 made by Yanmar. Then they switched to Hurth transmission.
So the output shaft was pitted and corroded. I put it in the lathe and turned it down until I got a smooth surface. The seal was a 50mmX30mm. I can buy a 50mmX28mm. The shaft is now 29.5 mm. I need to turn it down a bit more.
While I was turning it I noticed that the area where the seal contacted was hardened. It is only case hardened so I may have cut away most of the hard area. Does this have to be a hardened surface? Or can I get it to size polish it up and start assembling?

personally i would have it hardened..... take it to a automotive machine shop and have it hardened and polished.......

just wondering here why didnt you use a wedding band on the seal surface and lock-tite in in place......

regards

woody

 

[kloudie1]

Yup.. A Speedi Sleeve is a pretty good fit and works quite well for exactly that kind of wear.. For future reference..
http://www.skf.com/portal/skf/home/products?maincatalogue=1&newlink=4_5_3&lang=en
Yes, hardening would be best but you are sealing clean lube oil in a fairly clean environment.. It will most likely run a very long time without being hardened..

 

[Hermit Scott]

I pressed a bearing on that shaft that makes it difficult to chuck back in the lathe. Getting the bearing off may damage it since I have to grab the outside race with a puller to remove it.
My "friend" at the bearing company did me a solid and gave me a "discount". The two bearings cost me a total of $50. That doesn't seem that good to me. But most of the bearings I buy go through my Taiwanese manufacturer and are 1/10 the price I pay here. Literally 1/10 the price. A $40 bearing costs me $4.
It seems I have machined past the point of speedi sleeveing it. I may have to remove that bearing.

 

[Hermit Scott]

I bought a piece of 304 stainless today. I am going to attempt to remake the shaft.
I put the rear case of the tranny in a 20 ton press and tried to press the shaft out the wrong way(ooops) So I bought new bearings for it and it is out by 4 thousandths on the taper where the coupling goes on. I may have bent the shaft. The taper that goes throught the main gear in the tranny is visibly deformed. The gear is out by 10 thou on the outter edge of a 6" gear. All this may be ok but I am going to redo everything in this engine so I don't want to take a chance.
The shaft is 7" long, has 2 bearing seats 2 tapers and 3 sets of threads on it. I just got my lathe a few months ago. We will see how this goes.
I took the head to my friends house today who redoes Corvair race heads. We will start in on that this week. I will start a thread on the rebuild soon and post pics along the way.