MMC O Datum A

dave50

Registered
I have a true position call out that gives me mmc on datum A. Datum A is four points I level to. How would I compute bonus tolerance?
 

Michael_M

Trusted Information Resource
The bonus would apply to the form flowing down from the flatness (cylinder). I have found true position to be the most miss-used/miss-understood engineering drawing requirements with TP being used for other things.

***This is just my general rule at my work (and I train people at my workplace to follow it as well). Ignore all MMC/LMC from all datum locations (only apply MMC/LMC from hole diameter). Most of the time, if you need the MMC/LMC from Datum points you are already asking for trouble (it's not going to add enough to help).***
 

dave50

Registered
The bonus would apply to the form flowing down from the flatness (cylinder). I have found true position to be the most miss-used/miss-understood engineering drawing requirements with TP being used for other things.

***This is just my general rule at my work (and I train people at my workplace to follow it as well). Ignore all MMC/LMC from all datum locations (only apply MMC/LMC from hole diameter). Most of the time, if you need the MMC/LMC from Datum points you are already asking for trouble (it's not going to add enough to help).***
Thank you for the feedback.
 
Top Bottom