internal radial clearance = radial or diametrical 4

[electricpete]

When measuring sleeve bearing clearance, we usually identify the measurement as diametrical (vs radial).

Ball bearings have tabulated an internal radial clearance. I suspect it is in fact diametrical clearnance. Does anyone know?

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[Gerry45]

Yes, 'diametral' and 'radial' clearance are the same things. Radial is the more modern term, indicating the clearance is in the radial direction, as opposed to clearance in an axial direction.

 

[rnd2]

Given that radial expresses direction I think electripete is looking for confirmation as to whether actual clearance is x 2 or x 1 a stated "radial" clearance.

 

[diamondjim]

Radial Clearance and Diametral
Clearance are used as the same
terms and have the same values
in much of the literature.
It seems to be up to the author.
Radial Clearance is confusing
as some do think this means on
radius rather than in the radial
direction. Because of this some
still prefer using Diametral
Clearance.

 

[electricpete]

Thx. Rnd2 is correct I am wondering about the factor of 2.

I did some searching on internet and I think I agree now Gerry and diamondjim are correct that in the context of rolling bearings, the terms radial and diametral clearance are very widely used to mean the same thing. That answers my question that internal radial clearance is the total radial distance the inner ring can move compared to outer ring.

That definition certainly does not hold to other areas outside of rolling bearings.

See discussion of Petroff's equation for sleeve bearings:

http://134.153.24.18/~katna/index1/hydrodynamic_bearing.doc

"the film thickness h = c (radial clearance)"

Clearly in th context of this derivation of Petroff's equation, "radial clearance" is meant as 1/2 diametral
clearance.

Also in Bently Nevada literature, radial clearance is used in a manner which clearly indicates 1/2 diametral clearance.

My conclusion: radial clearance is an ambiguous term, but for rolling element internal radial clearance it has the same meaning as diametral clearance.

Thanks for the help.

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[rnd2]

electricpete, you deserve a star. By way of background, my company manufactures composite plain bearing materials. In discussions about clearances with machinists, we mean minimum running clearances (MRC)are over the diameter. I WISH I GOT A DOLLAR for every time I have to clarify this refers to the diameter and not the radius.