Replacing bearing on ..... anything

[sprintcyclist]

I replaced a few bearings on various machines lately and have learnt and been taught a lot.
Also removed a very badly seized part on a $10K machine with no damage to it at all.
Did some more research lately and am at the stage now where it is no longer just 'theory'.

I used to change bearings by pulling them off with a bearing puller, then tapping new ones on using a perfectly sized socket.
Now, when removing the old bearing off a shaft I clean and lube the shaft. Then use a heat gun to heat the bearing on the shaft.
Then it comes off much more easily.
To put the new bearing on the shaft, I put the shaft in a freezer for a few hours.
Heat the bearing up to about 100 degrees using a digital thermometer for about 10 minutes.
The new bearing slips in fully using hand pressure.

Normal bearings can take 350 degrees, so 100 is easy.
Bearings are very suspect to lateral force. Such as tapping them on with a socket or drift.

[sprintcyclist]

Would never have imagined that heating the 'outside' part to 100 degrees and cooling the 'inner' part to -20 degrees would give such a difference.

How much expansion/contraction is there in stainless steel for 120 degrees?

How much do you need, to make a difference?

[sprintcyclist]

yep, this is what I found

......... Wow.....I cleaned up the shaft and put the bearing & pulley in the oven for about 20 mins. I then used Cold Spray to cool the shaft.

It all went together so easy! Bearing slid all the way down and pulley went right on too just like butter.

Heat is the key! ......................

https://www.garagejournal.com/forum/sho ... hp?t=46113

Wonder what temp he had the oven set too.

[sprintcyclist]

..........Kettle full of boiling water can make huge difference to stuck bearings. Easy too..............

....................+1 for ice and boiling water. Either way around but the bearing needs to be cold and the frame hot. Oven not a good idea as these alloys are heat hardened and I’m not sure what oven temps would do to the material’s performance. ..............



............ Thanks to all those who replied.

Kettle of boiling water worked a treat. ............

https://singletrackworld.com/forum/topi ... t-an-oven/

AH, hot water. great idea. Readily available, great thermal conductivity and thermal mass. Will limit the temp rise to 100 degrees.
Never thought of that.

Ice on the shaft, hot water on the bearing? If you get ANY movement, it will slide off.