Snap ring for fractionally sized shaft
Snap ring for fractionally sized shaft
(OP)
So I have a design for a personal weightlifting bar I'm working on (pic attached). My question is regarding the snap ring size. The red external snap ring fits on the shaft (magenta) and the two washers on either side along with the internal snap ring further to the left prevent axial movement of the shaft. Now the shaft diameter is 28.5 mm whereas the snap ring in the model is for a 28 mm shaft. The groove depth is according to DIN standard for a 28 mm snap ring. Will this work?





RE: Snap ring for fractionally sized shaft
RE: Snap ring for fractionally sized shaft
RE: Snap ring for fractionally sized shaft
They're available everywhere. Try McMaster-Carr or Rotorclip.
RE: Snap ring for fractionally sized shaft
RE: Snap ring for fractionally sized shaft
RE: Snap ring for fractionally sized shaft
As for manufacturers, Rotorclip (www.rotorclip.com) is an international company. Contact them or their Indian distributor. I'm sure they can help.
As for the procedure to use standard rings on "non-standard" shafts, you have to create a "standard" configuration (shaft OD, groove OD, groove width) on your shaft to use the ring you select. Any good retaining ring catalog will give you those dimensions.
RE: Snap ring for fractionally sized shaft
On a separate note, if you've seen my drawing I'd like some advice. The sectional view that you see is of a shaft that'll rotate w.r.t the sleeve on two bushings, of which one is visible. Now there are no clearances between the washers and retaining rings except the mandatory clearance caused by the differences between the sizes of the snap rings and the widths of their respective grooves. The whole system's going to be lubed. Would the rotation be hampered due to the aforementioned lack of additional clearance between the washers and rings?
RE: Snap ring for fractionally sized shaft
Preferred Choice: Use the right sized ring.
If you cut down the groove, don't stop there. Don't forget the ring has to go over the OD of the shaft, so you will have to modify it too. Rings are designed to go over shafts of a specified size and still fit tightly in grooves of the specified size. Do not try to expand a ring to go over a shaft larger than its specified size.
"Would the rotation be hampered due to the aforementioned lack of additional clearance between the washers and rings?"
Absolutely! Always design in some axial clearance. How much depends on the precision of your manufacturing process. The main thing is you never want a metal-to-metal condition as your default. Metal-to-metal = friction.
RE: Snap ring for fractionally sized shaft
Right. Now the question is how much is some? Keeping in mind the clearances created by the difference in the snap ring sizes and groove widths, I already have 0.55 mm of axial play. Is this enough? If not could I adjust the washer thicknesses (by grinding them?) during the testing phase? I would also like to specify here that the whole washer, snap ring assembly is going to be bathed in some lubricant like SAE 40 (a.k.a 3 in 1 oil).
RE: Snap ring for fractionally sized shaft
Only you can make that call. You're the one that knows what the operational result might be.
Just make sure it never gets to zero no matter what tolerance buildup occurs as parts are made and assembled.