Back gear noise reduction?

LX Kid

H-M Supporter - Gold Member
H-M Supporter Gold Member
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May 26, 2015
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I know that straight cut gear teeth, on the back gears are noise prone, but is there a way to improve it a little? What about reducing the shims between the back gear where it's bolted to the head stock? Right now I have 10 thou on each side. Would that possibly encourage wear on the teeth? As far as I know that is the only way of adjusting gear meshing. It would be nice to quiet things down a bit when cutting threads!
 
Open gear grease helps.
 
My Clausing had horribly noisy change gears and back gears. No amount of adjusting made any difference.
 
I’ve had a lathe with straight cut gears and used several old South Bends. Agree with everything above. As messy as it is, the black grease with molybdenum in it may be the best lube for open gears. It may not make them quieter but at least you can be confident that the noise isn’t from poor lubrication.
 
I agree with David2011 and with several of the others. Straight cut gearing is naturally noisy. You could try adding 0.005"to and subtracting 0.005" from the 0.010" shims that are already there but that is your only possible option other than trying various lubricants. Which I would do. And I would strongly recommend that before changing the shims that you rig up some type of audio level meter and securely anchor it in a fixed location as the human ear is notoriously inaccurate for this sort of measurement. Plus most of the potential noise producers are not adjustable anyway.
 
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I’ve had a lathe with straight cut gears and used several old South Bends. Agree with everything above. As messy as it is, the black grease with molybdenum in it may be the best lube for open gears. It may not make them quieter but at least you can be confident that the noise isn’t from poor lubrication.
Maybe I'll try some of that Black Grease and maybe some motorcycle chain spray lube which is thick.
 
The motorcycle chain grease that I tried lubed the gears OK for as long as it sprayed. It clogged after just a couple of uses and the rest was left in the can. Since I didn’t try it again I don’t know if that’s a common problem. The moly grease is applied with a cheap acid brush so reliability is 100%. Three dozen brushes at Harbor Freight runs about $3.00.
 
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