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derekg
09-19-2010, 08:25 PM
Hi Folks,

I am pressing a collar onto a shaft that will have to sustain torsional loads during its lifetime. The collar will be welded in addition to the press fit, but I'd like the press fit to take the loading more than the weld. Are they any set guidelines or rules of thumb for the amount of interference fit given variables such as thickness of each component, temperature of each component (freezing the shaft, heating the collar), or available pressure to seat the collar?

Any tips will be appreciated.

Thanks, Derek

strokersix
09-19-2010, 08:33 PM
Machinery's handbook has the information you seek.

Welding after press fit may reduce the effectiveness of that press fit. If you feel you need belt and suspenders a taper pin to augment the press fit might be a better choice.

motorworks
09-19-2010, 08:37 PM
Hi
Shrink fit is always better than press If you can.
What's the size? I usually use 0.002-0.0025" plus on one over the other.
Heat to cherry and quickly install.Let cool to room temp before any needed machining.

Carld
09-19-2010, 09:11 PM
What size is the shaft and how wide and thick is the collar? I can tell you this, if you grind two V's in a slip fit collar opposite each other and weld the V's flush to the surface of the collar you will never have it move nor will you have to weld it to the shaft. This eliminates doing a shrink fit where you heat the collar and slide it on the shaft.

The slip fit, weld method allows you to put the collar exactly where you want it and then weld it. You will play hell moving that collar.

oldtiffie
09-19-2010, 09:26 PM
I like Carld's idea.

For shrink fits see:
http://www.google.com.au/#hl=en&source=hp&q=shrink+fit+tolerance&aq=1&aqi=g10&aql=&oq=shrink+fit&gs_rfai=&fp=62a3b4c4a0e828f3

http://en.wikipedia.org/wiki/Shrink-fitting

http://www.ameritherm.com/PDFs/shrinkfitcalcs.pdf