Inspection/Measurement of Parallelism

[mad4268]

I appologize if this post may be confusing or lacking information but I will keep up with it and respond when needed... I have a part with 2 machined surfaces (flats on a diameter, like the flat part of a washer). They are roughly 4" apart. About 3" from the one diameter is an assembled component which is also a circle with a flat on it, a ring. The goal is to measure the parallelism between one of the machined surfaces and this ring while the part sits on the other machined surface. Right now this is no problem as we use our CMM to accomplish this but we would like to have the assembly department be able to check this as they build the assembly right there in the shop. Does anyone have any clever ideas to accomplish this? I am thinking an indicator somehow located off one of the machined surface and measuring on the face of the ring. Any input would be greatly appreciated.

 

[Belanger]

I'm not quite picturing this, but keep in mind that when measuring parallelism, you need to establish a datum. And the datum is not the surface of the part, but rather a perfect plane formed by the highest points on the datum feature.
So this might be tricky if the parts are in the assembled state. (Was the CMM checking in this assembled state? If so, how was the datum established on the CMM?)

John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems

http://www.gdtseminars.com