reference length for perpendicularity

[ptweising]

I am trying to determine the perpendicularity of a pin hole to a machined surface. The machined surface is my reference plane. What I need to know is how deep into the pin hole do I need to go to get an acurate perpendicularity measurment.

 

[pso311]

A quick answer would be to use a projected hole tolerance. A rough estimate could be 2x's diameter. I'd have to check on these, but they're plausible.

 

[ptweising]

Thank you for your assistance in this situation. If you find any further information it would be greatly appreciated.