u/CrazyJoe29

Let’s say you’re writing an email and you need to tell somebody that the existing ⌀220 [8.661] diameter needs to be increased to ⌀240 [9.449]

Would you write ⌀220 or ⌀220mm. None of the technical drawings I see in my role show units which is rarely a problem, I’ll guess because a mm is 25 times smaller than an inch, but once I’m writing the dimensions it’s slightly more ambiguous.

Final boss: How do you call out a metric thread for a shop that uses inch tooling?

DRILL ⌀0.203 BY .750 DEEP
TAP M6X1 BY .563 DEEP

Probably this is better:

DRILL ⌀0.203”BY 0.750” DEEP
TAP M6X1.0 BY 0.563” DEEP