Membership Services

Re: Re: True Position MMC

[ Home ][ Forum Archive ] [ Active Engineering Forum ]

Posted By<" ">John-Paul Belanger on August 31, 2002 at 22:30:13:

In Reply to: Re: True Position MMC posted by on August 28, 2002 at 08:14:06:

Yes -- I think more info is needed to specifically answer your question... Are the two holes toleranced with the same feature control frame? If so, then the hole-to-hole distance is affected by taking a bonus tolerance from both! (Bonus tolerance is the actual hole size minus the smallest allowable hole size. This is then added to the stated position tolerance.)
But if one hole is a datum that the other hole is toleranced to, then we have to look at that datum letter as referenced in the feature control frame. If it is RFS, then no extra tolerance is carried over from the datum; just the toleranced hole gets bonus. But if the datum is also MMC, then you're back to both holes getting the bonus (although the extra amount from the datum is not usually called bonus, but often "shift" tolerance).

Follow Ups

Subject: Re: Re: Re: True Position MMC

Comments:: Yes -- I think more info is needed to specifically answer your question... Are the two holes toleranced with the same feature control frame? If so, then the hole-to-hole distance is affected by taking a bonus tolerance from both! (Bonus tolerance is the actual hole size minus the smallest allowable hole size. This is then added to the stated position tolerance.) : But if one hole is a datum that the other hole is toleranced to, then we have to look at that datum letter as referenced in the feature control frame. If it is RFS, then no extra tolerance is carried over from the datum; just the toleranced hole gets bonus. But if the datum is also MMC, then you're back to both holes getting the bonus (although the extra amount from the datum is not usually called bonus, but often "shift" tolerance).

[ Home ][ Forum Archive ] [ Active Engineering Forum ]