Counterbore/countersink hole combination

[helibum]

I wish Fusion 360 had the ability to combine counterbore with countersink when creating holes with the Hole tool. The use case I have in mind is a surface where you need a countersunk screw to be flush but you don’t have enough room to oversize the countersunk area. Every flathead screw has a rounded lip at the top of the head, so simply making the countersink the diameter of the head results in the top of the head being above the surface.

Does anyone have a quick workflow they use to accomplish this, possibly a script?

[jhackney1972 · Accepted solution]

The easiest thing to do, in my opinion, is to place your counterbore then come back and create a chamfer on the clearance hole at the bottom of the counterbore. 

[helibum]

I should have thought of that. It's a little computationally awkward, but it works. BTW, the formulas for chamfer distance and angle are:

Distance = (counterbore diameter - hole diameter) / 2

Angle = 90 - (countersink angle / 2)

[jim]

I recently needed to do this also. After looking at this answer it gave me an idea. I offset my sketch into my part by the distance I wanted the counterbore to be, then I created two sets of holes, one that was reversed that was the counterbore, and the other that was the countersink.

This worked in my case just fine.