Backgear rebuild complete

rke[pler · Feb 11, 2003

After running down the proper bearings for the output shaft in my '56 backgear and completing the reassembly with new gaskets the new backgear is almost silent in direct drive. There's some wear on the countershaft under the big gear, so there's some noise in backgear, but it's not bad.

The quiet was enough that I could then hear noise in the gearbox when set for feeding, and tracked part of it to the engagement of the drive gear control and the rest to grungy bearings in the flat belt idler. After cleaning up the selector on the first and cleaning and regreasing the latter the cooling fan now makes more noise than the lathe working.

AlfaGTA · Feb 11, 2003

rke[pler: I hope i have a similar expirence when i get my EE going. When i first got it it was so noisy that i could not stand it, and i promptly took the back gear box apart. i changed all the bearings, and made new gears as well. I have not run it yet as i also got into doing the bed and scraping everything true. Hope that later this summer all will be complete and i hope all will be quiet! Congratulations on your efforts. Ross

Bruce L · Feb 11, 2003

I have a mid 60's 10ee. My back gear mechanism is very quiet running in reverse. But it is quite noisy running forward. I suspect that is typical but does it indicate more gear or bearing wear?
Bruce L.

AlfaGTA · Feb 13, 2003

I suspect the gears. Bearings use the same elements going either direction. Gears on the other hand use a different surface going forward as opposed to going in reverse. The contac forces are delivered on the opposite side of the tooth when running in reverse! My box was very noisy, and upon inspection i discovered the small pinion was worn and pitted. What i discovered is that on my machine (63') the gears are not a standard pressure angle. Turns out that they are somewhere around 17 degrees. Made a complete new set at 20 degrees so they would match. Machined from 4340 pre heat treated to 38-40 RC. Gear teeth shapped and then gears nitrided for final hardnes. Ross

gjrepesh · Feb 16, 2003

I had the same problem with mine. Back gear noisy in forward and quiet in reverse. I found both gears on the top shaft had flats worn into the teeth. That's the side for forward. The opposite side of the teeth looked fine and those work during reverse. I've made the 24 tooth gear(steel) and am now making the 64 tooth gear(cast iron). I don't want these hardened because I want them to wear instead of the two gears that mate, direct drive. They seem more difficult to replace. Any thoughts on this?

AlfaGTA · Feb 18, 2003

Gjrepesh: be careful if you are not replacing both gears in a mesh pair! They have a non- standard pressure angle and will run very noisy!!!! Ross

gjrepesh · Feb 21, 2003

Ross, Very interesting on the pressure angle. How did you determine 17 degrees? I finished my second gear. When I get the gear box together I'll post on how it runs.

Gary

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Backgear rebuild complete

rke[pler

Diamond

AlfaGTA

Diamond

Bruce L

Plastic

AlfaGTA

Diamond

gjrepesh

Cast Iron

AlfaGTA

Diamond

gjrepesh

Cast Iron

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