[To...] Posted April 22 Share Posted April 22 Would it be safe to assume that Datum B would consist of a Best Fit Bore pattern of 54 holes? Also, any thoughts on separate flatness call out? Is the upper tolerance in a free state and the lower in a restrained state?datum b equals 54 holes.JPG Link to comment Share on other sites More sharing options...
[Cl...] Posted April 22 Share Posted April 22 Why would the lower be in a restrained state? I see no datum in the attachment. Link to comment Share on other sites More sharing options...
[To...] Posted April 22 Author Share Posted April 22 Please sign in to view this quote. I believe I have answered my flatness question. Are you referring to datum B????Capture2.JPGCapture.JPG Link to comment Share on other sites More sharing options...
[Ri...] Posted April 22 Share Posted April 22 Hi Tom, That would be my initial thought on the interpretation. Hopefully they have instructions on the constraint. Link to comment Share on other sites More sharing options...
[To...] Posted April 22 Author Share Posted April 22 Please sign in to view this quote. Nothing clear. I got to thinking, why would they need a tolerance on the surface if it is being clamped down against a flat surface. Then, it dawned on me, When you clamp the part down with Datum A facing up, you would be at the mercy of how good the opposite side was. Link to comment Share on other sites More sharing options...
[Cl...] Posted April 22 Share Posted April 22 Please sign in to view this quote. Type-0 meant note. Used to see this type of note a lot in Aerospace. Link to comment Share on other sites More sharing options...
[Ri...] Posted April 22 Share Posted April 22 I'm glad none of my aerospace customers showed me this one because I'd have told them no. Hahaha. I understand that they are putting a tolerance on your constraint essentially, but wow they really have a huge gray area there on what you are allowed to do to achieve it. I've certainly seen the aerospace guys use the max allowable weight per square foot to help with flatness, but this is something new to me. I'm not a fan of having a constraint allowance, but no clear direction on how to properly constrain the part. At least the automotive guys get it right (for the most part). Link to comment Share on other sites More sharing options...
[Ri...] Posted April 27 Share Posted April 27 Please sign in to view this quote. I have run into this many times. Each time I was provided information by the customer on how the restrained state was to be controlled. Link to comment Share on other sites More sharing options...
[Cr...] Posted May 2 Share Posted May 2 Hi Tom, I've been running into parts like this a lot lately. Check this youtube video out, it might give you some direction on datum B https://www.youtube.com/watch?v=nODmERQi4gY&t=582s Link to comment Share on other sites More sharing options...
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