Chamfer square hole?

[stuart_rubin]

I have a square hole with chamfered sides. (In fact, the holes will be the female side for an inlay.) I was planning to use a 30-degree chamfer bit (which is also a 60-degree V-carve bit!) to make the edges, which are 30-degrees. The bulk of the hole is cleared with a simple pocket operation and a flat endmill. The tool paths I generate for the chamfer are leaving rounded corners, not making sharp bevels (like V-carves), which is not unexpected, but not what I need.

What is the right operation (or combination of operations?) to carve these holes out?

Thank you!

[matty.fuller]

In a 3 axis machine you might get what you want by using Trace to drag the tool up the corner edges.

[programming2C78B]

Are you using the Engrave toolpath? You'll then want to do 2D contour with rest machining on to remove the final island leftover in the corners (on the floor)

[stuart_rubin]

I'm not sure if this the right or best way to approach this, but I ended up with three operations. (I have not actually milled this yet, so I cannot be sure it will work in practice.)

1. 2D Pocket w/ flat endmill (bulk clearing of the pocket)

2. 2D Pocket w/ chamfer bit. Use rest machining, tool diameter is same as flat endmill. Corner radius is 0. (Thanks @programming2C78B for the tip to use rest machining!)

2. 2D Trace w/ chamfer bit. Geometry is inner square and the four vertical corner edges. This gives me the sharp corners.

I'm still not convinced this is the best way so I'm open to suggestions! Thanks