Chamfer True Position

[Big Red]

How do I program a chamfer and report it's True Position and Diameter?

I have a .300 thru hole (Datum -A-) and it has a large chamfer on top. The Chamfer diameter at the extreme top is .650. This chamfer needs to be True Posistion to the .300 thru hole though I've never had this sort of callout and am lost in translation.

I took a series of 4 lines on each quadrant of the chamfer, pierced these lines as points to the top plane then created a circle. This did not work well.

I've never done a cone. Is a cone the proper method?

Thanks in advance.

3.7 MR2

[Matthew D. Hoedeman]

That's pretty much what I would do, measure a cone, measure a plane on the surface around the cone, intersect them to make a circle, then TP that circle.

[Roberto]

How do I program a chamfer and report it's True Position and Diameter?

I have a .300 thru hole (Datum -A-) and it has a large chamfer on top. The Chamfer diameter at the extreme top is .650. This chamfer needs to be True Posistion to the .300 thru hole though I've never had this sort of callout and am lost in translation.

I took a series of 4 lines on each quadrant of the chamfer, pierced these lines as points to the top plane then created a circle. This did not work well.

I've never done a cone. Is a cone the proper method?

Thanks in advance.

3.7 MR2

Is this a sheet metal part?
What I would do is measure the 0.650 dia. hole with sample hits for true position. And measure the 0.300 thru with pin gage.

[george frick]

what matt said

[John Kingston]

Measure a cone by taking hits at 3 levels, similar to a cylinder.
And then What Matt Said.