alignment between hole and slot with unilateral tolerances 1

[lastviking]

Hi all,

I need to tightly hold the alignment between a hole and a slot. The hole has a unilateral postiional tolerance from the tertiary datum and I also want to allow a more generous unilateral tolerance between the slot and hole. The competing priorities I described seem to preclude the use of composite control frame but maybe I'm missing something.

My first attempt at GD&T is attached (mm dims), but it was rejected since I was told I can not GD&T a centerline between features.

Any ideas?
Jim

 

[KENAT]

lastviking, I think maybe there's a mix up on terminology. Assuming you're working to ASME Y14.5M-1994 and have a copy available then take a look at figure 5-41 & the text of section 5.9.

Essentially you can put one tolerance in one direction, and a separate tolerance in another. I think this will meet your needs.

KENAT,

Have you reminded yourself of faq731-376 recently, or taken a look at posting policies:

http://eng-tips.com/market.cfm?

What is Engineering anyway: faq1088-1484

 

[lastviking]

Thanks Kenat, that does get me part way there. Any idea how to utilize unilateral tolerancing with true position? I don't see that in Y14.5M-1994.

Or do I just need to change my nominal to the center of the unilateral zone and make it bilateral?

 

[KENAT]

Your latter option is probably the way to go with position tolerance.

With surface profile you get more options on unequal bi-lateral or unilateral but I don't think it's appropriate here.

KENAT,

Have you reminded yourself of faq731-376 recently, or taken a look at posting policies:

http://eng-tips.com/market.cfm?

What is Engineering anyway: faq1088-1484