Milling sharp inside corners

[Tech3]

Normally, sharp inside corners are not practical in milling because the cutter is round. However sharp corners are natural at the four bottom edges of a recessed pocket or slot.

If the recess or slot extends to the edge of the part you can achieve a sharp inside corner at the surface when viewing the part from that edge. Further, by bolting two such parts together you can get the effect of a square hole on a milled part.

If you can't cut to the edge of the part and need to fit a part that has sharp corners into a rectangular recess, consider removing an arc of material at the corners. Here's how:

* Draw a circle of the desired corner radius - say .25".
* Make 3 copies.
* Drag the circles so that their top snap point snaps to each corner of the rectangle.
* Rotate each circle around the rectangle's corner the appropriate multiple of 45 degrees.
* Select everything.
* Line | Intersect.
* Delete the interior segments.