Retainer Ring Shaft Tolerance

[Brian Selle]

Originally Posted by Cory

I'm reading the question differently than most.

It sounds like the OP is asking "Should I add some small amount of clearance to my width between snap rings so when I assemble everything the parts aren't stacked line to line between the rings?"

The answer to that is yes. Your tolerance stackup will inevitably lead to it being impossible for you to get the 2nd snap ring on without some slop.

You do not want that slop to be in the groove though. You should cut the groove .039 like McMaster says. Just add in .005-.010 to the distance between grooves.

Yes this is what I was looking for... thank you! I should have been more clear... my example is that we are designing a new transmission and the tolerance stack up of all the gears, sprockets, bearings, frame, wheel, etc along the main output shaft may add up to the point that the end ring wouldn't fit. There is a spacer we could shave down to most likely solve any issues but wanted to avoid having to machine a longer output shaft. We then started to wonder about the tolerance stack up for a simple WCD axle (sprocket, bearings, wheel, etc). I couldn't find any manufacturing tolerances for most of the parts to make an estimation of what a worst case would be. 0.005-0.010" sounds good.

[roystur44]

Here is a tip when assembling our transmissions. We use fiber washers as shims to get the spacing just right between parts on a shaft.

http://www.mcmaster.com/#fiber-washers/=k1pki7

[Brian Selle]

Originally Posted by roystur44

Here is a tip when assembling your transmissions. We use fiber washers as shims to get the spacing just right between parts on a shaft.

http://www.mcmaster.com/#fiber-washers/=k1pki7

We were thinking of using a laminated washer like:

http://www.mcmaster.com/#round-laminated-shims/=k1q52f

Does the fiber hold up well? Maybe adds a little give?

[Paul Copioli]

My absolute favorite for handling the slop take-up is a wave washer. Industrial robots use them everywhere in their gearboxes and the premier industrial gearbox companies that sell to industrial robot companies all use them. The McMaster versions are located here: http://www.mcmaster.com/#wave-disc-s...ashers/=k375io

These work especially well for gearboxes using spur gears.

Paul