hexagon logo

Mmc

Can’t believe most inspectors and especially engineers don’t know this!

On a hole diameter MMC = Actual measured hole size minus the smallest allowable size which is the MMC condition… max material.

So for TP .5 on a 10.0 +/- .5 hole that measures 10.1
You get .6 Bonus (actual size 10.1 minus the smallest size 9.5 = .6) this .6 extra tolerance is then added to the given .5 TP tolerance for a grand total of 1.1 tolerance.

For a solid pin or outside cylinder it’s outside diameter, same concept. Largest allowable size minus the actual = Bonus Tolerance.

BONUS TOLERANCE =
DIFFERENCE BETWEEN MMC SIZE AND ACTUAL SIZE! ADDED TO GIVEN TP TOLERANCE IN THE FEATURE CONTROL FRAME.​
Parents
  • Slightly off topic, but still along the lines of engineers not knowing something...

    We have a customer who sent us a print with rather tight GD&T for the nature of the part. After discussions with them, their design engineer flat out stated, "I really don't know too much about GD&T." Astonished


    I have never had one admit it! lol but there is definitely a clear undertraining of GD&T for new engineers.
Reply
  • Slightly off topic, but still along the lines of engineers not knowing something...

    We have a customer who sent us a print with rather tight GD&T for the nature of the part. After discussions with them, their design engineer flat out stated, "I really don't know too much about GD&T." Astonished


    I have never had one admit it! lol but there is definitely a clear undertraining of GD&T for new engineers.
Children
No Data