Perpendicularity Problem

[Willigan]

Hi all! I apologize in advance for being dumb.

I'm having an issue dimensioning a perpendicularity callout correctly. My part is flat with a hole (Datum D) drilled through. A horizontal slot is milled through the drilled hole, creating a top and bottom hole. Datum E is the thickness of the part. Now the feature control frame says D | Perp. to | E @MMC | Diam. 0.1 @MMC | Projected 100mm | I guess my question is what do I make Datum E be? I measured a plane at the top of the part and one at the top of my fixture, with which to costruct E. Now am I correct that, in order to correctly apply my bonus to E, E has to be some circular feature? And if I do apply MMC to the cylinder, will that be right, because MMC for E would be a thicker part, not a larger cylinder. Sorry, I'm really new to this. Thanks for any help.

-William

[bw_bob]

It sounds like datum -e- is a plane and your primary datum. Not sure how you apply bonus to that. Would not be the 1st time a engineer used GD&T incorrectly. If you could post a picture of your print callout i'm sure you will get a reply.

[John Kingston]

I would measure the 2 planes that create datum -E- , then create a midplane. Find your locations to that datum and calculate TP myself using the MMC bonus.

[bw_bob]

I would measure the 2 planes that create datum -E- , then create a midplane. Find your locations to that datum and calculate TP myself using the MMC bonus.

Is datum-e the c/l of 2 surfaces. If thats the case john is correct. Or is it to the top or bottom of 1 of the surfaces.