I'm in a bit of a quandary.
I know how to machine this, but I don't know how to call it out on a drawing.
I'm working on the mechanical drawings for a small electronic enclosure, to modify a purchased case by drilling some holes for some connectors.
The holes are 1/2" diameter, and are on an end of the case that forms one wall of a well: the other wall is formed by the molded-in battery box about an inch away.
In order for the circuit board to fit, it must be tilted at about 40 degrees, the connectors that go through the above-mentioned holes are inserted, pushed home as far as they'll go, then the whole shebang is rotated into place.
In order for this to work, the top edges of the 1/2" holes need to be cut at about a 40 degree angle. The end effect is that on the outside of the case the holes are round, but on the inside they are oval.
Assuming that the above discussion makes sense, how would one call this out on a drawing? Just draw the hole outlines, and leave it to the machinist to figure out how to make it all work?
The case is ABS plastic, and the way that I'm making it is to machine the holes on a mill, but make the 40 degree chamfer with an x-Acto knife. But the case manufacturer is putting themselves forward to machine the case for production. I'm going to send them a case with all the bits installed, but I'd like to send them a drawing that could at least be construed to be correct in some sense.
Suggestions welcome. Thanks.