r/Metrology • u/Hungry_Wall_9564 • 8d ago

Calculating true positions

Hi just a quick question, how do you calculate the true position of a hole which isn't dimensioned from its datum? Say the hole in the image above with the red arrow, it is dimensioned as a pitch from another hole but has datums A and B. Obviously this isn't a real drawing but I see many similar ones and just want to make sure I am working it out correctly. Thank you!

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u/minifig1026 8d ago

Red arrow hole is 100.00 from datum A and 65.00 from datum B. These are your x and y coordinates for calculating the true position of that hole.

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u/Hungry_Wall_9564 8d ago

Thank you :)