.625" external hex as a Datum

[d.evans]

How would you construct this?

I do have the CAD.

So far, I tried six planes (one on each surface of the hex) and then constructed a "Constructed Set Feature" from all six. It ended up putting a single point on the Graphical Display. Not sure if this is going to work. Any ideas?

[#2#]

How would you construct this?

I do have the CAD.

So far, I tried six planes (one on each surface of the hex) and then constructed a "Constructed Set Feature" from all six. It ended up putting a single point on the Graphical Display. Not sure if this is going to work. Any ideas?

Don't know if this will work but this would be my first try.

Measure 12 lines 2 on each side of the hex at two different heights. Construct points where the lines intersect for each of the heights. Use these points to construct a cylinder.

Just a guess and maybe someone else has a better way or a reason why that way would be bad.

[cmmguy]

Here is one way....

Line, Line, Line, Line, Line, Line
Intersect, Intersect, Intersect, Intersect, Intersect, Intersect
Between each point pair construct a....
Midpoint, Midpoint, Midpoint, Midpoint, Midpoint, Midpoint
Construct circle from all of the midpoints.
Set datum on center of circle.

[d.evans]

these ideas look good. Thanks.

[Matthew D. Hoedeman]

Measure and re-measure a 6-hit external circle. As long as the HEX is correct, a 6-hit circle, re-measured, should hit at the same portion of the flat each time. It will depend on the 'slop' in your machine, if it is sloppy, then this wouldn't work very well, then you would have to go with the 6 lines, or even 3 lines, one on every-other flat, then construct 3 intersect, etc..

[Paul Sarrach]

Thats how I do it, I also use prehits and I will adjust my angle to try to get into the center of the flats.