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timh
07-16-2007, 10:58 AM
If you make a spindle/axle for a bearing how tight should the fit be? Slide on our press fit? Say a 5/8 dia.

JCD
07-16-2007, 11:56 AM
About .0001" to .0004" interference, depending on bearing design, journal surface finish, load, speed, lube, service factor.

Swarf&Sparks
07-16-2007, 12:06 PM
what kind of bearing?

Evan
07-16-2007, 12:50 PM
About .0001" to .0004" interference, depending on bearing design, journal surface finish, load, speed, lube, service factor.

As well as expected service temperature range and the phase of the moon when installed.

Swarf&Sparks
07-16-2007, 12:52 PM
Moon phase is only relevant to phos bronze!

timh
07-16-2007, 01:30 PM
This would be for a wheel bearing light duty use.

Swarf&Sparks
07-16-2007, 01:38 PM
"wheel bearing light duty use"

sorry Tim, you're gonna have to a lot more explicit if you want a meaningful answer.

"light duty" for a garden wheelbarrow or
"light duty" for an occasional run at Bonneville on a 1920 Indian Scout?

Pardon me if I sound facetious, I've heard sillier questions asked by engineers.

tattoomike68
07-16-2007, 02:22 PM
This would be for a wheel bearing light duty use.

It its on a haul wagon that you pull behind a tractor then .001 clearance slide fit is fine. you wont need a hammer and chisle to change the bearing if it ever needs it.

It may be a bit tighter if its on a boat trailer that goes down the road at 65 MPH.

Rich Carlstedt
07-16-2007, 11:50 PM
If the spindle is stationary, as in an automobile front wheel bearing, The spindle should be loose sliding fit, and the OD should be a press fit.
If the spindle turns, then it is opposite, with the spindle being a press fit, and the OD a sliding fit.
Rich
"Loose" is .0005 clearance
"Press" is .0003 interferance

John Garner
07-17-2007, 03:37 PM
The bearing race that rotates relative to the load should be tightly fitted, the bearing race that is stationary relative to the load should be slip-fitted.

Swarf&Sparks
07-18-2007, 10:14 AM
I'll happily do a 0.001" interference fit on an ali bearing block (outer race), just press it in with the bench vice.

I wouldn't like to try that on steel or cast iron though.

Colchester John
07-18-2007, 07:06 PM
The simple old rule was "a thou interferance per inch of diameter". i.e. 1/2" = 0.0005", 1" = 0.001" etc.
This has always worked well for me...!

Ken_Shea
07-19-2007, 12:27 AM
While the "Expert" engineers will spout the fact that bearings all have a specific fit per use, I have to grin, because I know from experience that in reality, more often than not, all those extremely precise specs get amazingly forgotten while in the manufacturing mode.
Except for the bearings themselves.