True Position on Bolt Circle Diameters

In this Question Line video, Jason answers the following question regarding true position on a bolt circle diameter: 

I have an 8-hole bolt pattern with a basic of (Ø1.350) and 8X(45°) basic. The position tolerance is TP|Ø.005|A|B|. My question is when the basic bolt pattern is Ø1.350 and the actual diameter is Ø1.352, how does the .002 figure into the outcome of the actual position of .005. Each of the 8 hole positions are well within the tolerance and the 8 hole bolt circle is also well within the .005 bolt pattern tolerance. Is the .002 difference in the basic hole pattern going to make a difference in the position of the bolt pattern? The position of the bolt circle is .0015, does that change because of the .002 oversize condition of the Ø1.350 which is a 1.352?

In answering this question, Jason walks through the above drawing to explain how the feature control frame is controlling each hole to a position tolerance, rather than controlling the bolt circle diameter or location. 

Looking for answers to your GD&T questions? Submit your question to our GD&T experts at the link below! 

https://www.gdandtbasics.com/share-your-gdt-questions/ 

* If you are a current student, reach out to us directly and we will get you into contact with your instructor. Active students’ questions receive a direct response within 24-48 hours.