USING UNEQUAL SYMBOL FOR TOOL SETTING

[UGMENTALCASE]

Good Morning,

I've got a couple of brackets which I'm setting on assembly on my tool. I've previously used the 'U' modifier symbol on other brackets on other jobs, to indicate which way to have the surface tolerance, in or out, however can I use this for assembly setting?

I want to set two brackets to a CAD MODEL, which at nominal position the face of the bracket is touching the component face. How would I tell the fitter to set the bracket to nominal or minus, i.e away from the nominal face so it wouldn't cause any clashes.

Can I use the 'U' modifier? A bit like the image attached?

I appreciate I could just leave a nominal gap, but I'm intrigued

Thanks in advance

 

[Belanger]

A couple of things here... First, the callout you've attached really wouldn't make sense because the number you've placed after the U is larger than the number before the U. Maybe that was just a typo on the number of decimal places.
But yes, in general you can use a profile tolerance on an assembly, just like on a detail part. I think you would want a zero after the U, because you are trying to avoid interfering with the mating part. Thus, you don't want any deviation on the "air" side; you want all deviation into the part on the "material" side. (The number after the U is always the amount on the "air" side.)

Also, if the surface is flat or contoured, that may affect how we answer the question. If it's flat then using the U may be difficult or even pointless.

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

 

[powerhound]

Uh oh, JP. Now you've really done it. Here it comes...

John Acosta, GDTP Senior Level
Manufacturing Engineering Tech