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Message No. 11010, Started by bmayville on 04/14/03
My question is about circular runout.  Picture this: a design with a T-Shaped cylindrical part (looks like a bolt with a large head and no threads on the shaft; I'll refer to these parts as the "flange" and the "shaft" respectively).  This is supposed to fit into a cylindrical bore.  There is a circular runout called out on the FOS of the "shaft".  The feature control frame refers to the axis of the "flange" as the primary datum and the "flange" underside surface (perpendicular to the axis) as the secondary datum.  I know the worst case boundary of the "shaft" is affected.  However, I was told by a superior that I do not need to include the runout in my calculation, I only need to check the FOS limit with the mating bore FOS limit (I was told the runout does not affect my interference calculation because the assembly is cylinder to bore FOS only).  Was I instructed correctly?  I know each circular diameter along the "shaft" must meet the size requirements, but couldn't one "circular area" along one part of the "shaft" be shifted in one direction and another "circular area" further down the shaft be shifted the opposite direction, thus causing an interference due to the runout tolerance (i.e. the runout WOULD affect the interference calculation)?  I appreciate anyone's help or comments.    
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Follow-up Messages (15)
now add to this ownership that is only interested in a short-term buck and ...
No. 11042, Posted by gerdb on 04/17/03, 11:28 PST.
by the way, I rather like your idea for the drafting course, think you coul...
No. 11040, Posted by rorschach on 04/17/03, 09:16 PST.
yes, I've seen my share of crappy drawings, things that were dimensioned in...
No. 11039, Posted by rorschach on 04/17/03, 09:13 PST.
The first 3/4 of my machining career was for my dad's business. He was REA...
No. 11038, Posted by rolschwarz on 04/17/03, 06:17 PST.
glad to hear some confirmation now take this machinist-toolmaker scenari...
No. 11037, Posted by gerdb on 04/16/03, 18:10 PST.
What's becoming more prevalent with 3D CAD is the CAD operator who can neit...
No. 11036, Posted by rolschwarz on 04/16/03, 17:30 PST.
I was only giving a hint as to actual machineshop practices, not making rec...
No. 11035, Posted by gerdb on 04/16/03, 16:15 PST.
I agree, what should be used here is not Circular runout, but FIM. (the two...
No. 11032, Posted by rorschach on 04/16/03, 11:23 PST.
really, it sounds like someone needs to rethink the whole GDT scheme.
No. 11023, Posted by rolschwarz on 04/15/03, 13:27 PST.
I definitely understand your point. Obviously worst-case scenarios by prin...
No. 11022, Posted by bmayville on 04/15/03, 12:33 PST.
Yes, but the flange OD is has plenty of clearance between it and it's match...
No. 11020, Posted by bmayville on 04/15/03, 12:26 PST.
Does the shaft sit in a stepped bore, with both the flange and shat in matc...
No. 11019, Posted by rolschwarz on 04/15/03, 11:47 PST.
the way I see it, he is right. Run-out refers to the theoretical centerlin...
No. 11017, Posted by gerdb on 04/15/03, 10:41 PST.
No additional callouts on the shaft. I started my current job about 1 mont...
No. 11015, Posted by bmayville on 04/15/03, 07:36 PST.
Sounds about right to me. Hard to tell for certain without pictures and kn...
No. 11014, Posted by rolschwarz on 04/15/03, 06:16 PST.
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