Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Radial Run Out Stack up

Radial Run Out Stack up

Radial Run Out Stack up

I have a roller bearing, the cup and cone have a circular runout tolerance. The hub that the shaft and bearing are inserted also have a circular run out tolerance.

I am a trying to understand if the cup and cone tolerances will add/stack up and affect the hub run out?

RE: Radial Run Out Stack up

The run-outs could stack up in many different ways.
Would the function of your machine be affected if the hub and bearing runouts were at the theoretical maximum and assembled to create the greatest runout?

Precision machine tool spindle builders will position the race and (usually rotating) shaft runouts to reduce the assembly runout.
Super precision spindle bearings have the runout high spots marked to allow optimized assembly.

RE: Radial Run Out Stack up

Thanks Tmoose.

Are there any good references for doing a radial run out stack up of bearing and hub/shaft assembly, that you can suggest ?

RE: Radial Run Out Stack up

Runout is, worst case, nominally twice the radial offset; if the runout of the bore to the OD is 0.0002, then the offset of the axis is 0.0001. (inch tolerance) Radial stack is linear stack + phase. In phase they add, 180 degrees out, they subtract.

RE: Radial Run Out Stack up

This is for a wheel bearing. I am trying to find the radial stack up of the inner and outer bearing and the hub.

Circular Run Out
Inner bearing = 0.070
Outer bearing = 0.070

Hub = 0.075

The datums A-B are the bores.

Could I also find the lateral runout from these tolerances ?

RE: Radial Run Out Stack up

Axial runout from radial runout?

RE: Radial Run Out Stack up

Let's come back to the lateral run out. First I would like to see if I have the right idea for the radial stack.
Would radial run out stack simply be bearing circular radial tolerance + the hub radial tolerance ( 0.070+0.075) = 0.145

RE: Radial Run Out Stack up

Runout is between a surface and an axis. In a bearing there is runout between the bore and the inner race and another between the outer race and the outer surface and between the bore and the outer surface. The hub has runout between the bearing bore and other surfaces, though except for the radial location of the studs / wheel bolt holes, it doesn't matter much.

Are you looking at runout around the bearing bore or about the outer race as the hub turns on the bearing?

RE: Radial Run Out Stack up

I took the run out tolerance of the inner race and outer race and summed them to get 0.070. I.e, Inner race r/o tolerance 0.035 , and outer race 0.035.

I am looking for the runout on the surface of the hub, and how both bearings run out contributes to it.

RE: Radial Run Out Stack up

0.070 is the value to use if the bearing is seized with rust and the hub is spinning on the hub shaft.

RE: Radial Run Out Stack up

sorry, I guess I am missing the point. Thanks for trying to help. It's probably the way I am presenting the question.

RE: Radial Run Out Stack up

What is the surface that controls the axis of rotation?

RE: Radial Run Out Stack up

I believe it would be the hub bore, the surface that the bearing cones insert.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close