Circular runout normal to datum axis 2

[dave048]

We have a barrel shaped part about 20 inches in diameter with a one inch wide flange around the perimeter perpendicular to the barrel axis. The GD&T callout on the flange is circular runout (not total) to the axis of the barrel. In other words perpendicular runout. The shop has been checking this by placing an indicator on the flange tracing a single track close to the barrel and rotating the part on the barrel axis. The part is OK. Inspection has found that if they choose a single circular element track further away from the barrel, which is interrupted, the part is out of tolerance. The B/P does not specify where on the flange to place the circular element track. The question is, do both of the single circular element tracks have to be within tolerance? GD&T 1987 applies.

 

[axym]

All of the circular elements have to be within tolerance, from the furthest inboard to the furthest outboard.

BTW, I'm not sure which standard "GD&T 1987" refers to. There was ANSI Y14.5-1982 and ASME Y14.5M-1994.

Evan Janeshewski

Axymetrix Quality Engineering Inc.

http://www.axymetrix.ca

 

[powerhound]

First of all there is no 1987 GD&T standard, it's either 1982 or 1994, or if you're really up to date; 2009. Regardless, the interpretation of circular runout is the same. There should be an arrow pointing to the surface and it's the entire surface that should be checked in the absence of any zones that may be shown. If the surface is interrupted by design, and it's the interruption that is out of tolerance, then that's probably okay. If the interruption is causing the specified surface to bow or warp out of tolerance, then it's probably NOT okay. I think that some on this board, including myself, might need to see what you're talking about to be sure the reply is to the correct question.

Powerhound, GDTP T-0419
Production Manager
Inventor 2009
Mastercam X3
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SSG, U.S. Army
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[dave048]

Thanks guys, exactly what I thought. Sorry about the 1987 date I didn't think it mattered but just in case I threw it in at the last minute with out verifing. The interrupted surface is gaps between bolthole bosses.

Powerhound,
if you get a flight safety alert on one of your favorite helicopters you will already know what it's about.