Ken Marquess and I made this simple dovetail cutter for cutting the ways for Aloris toolpost holders. As you can see it uses a single triangular insert. This one uses a TCMM-321 and lock screw, borrowed from a lathe holder. (The holder is the MSC "house brand" 5/8" shank)

The only constraint is that it is a positive rake insert so as to clear the cut, and that the insert is mounted to cut a large enough diameter to clear the insert. In this case, 1-1/2"d was safe.

The insert is mounted in a recess set below the centerline by the insert thickness, i.e. so the plane of the top of the insert goes through the cutter axis. The insert overhangs the edge of the pocket about 1/32".

The shank is made from a scrap of 1-1/2"d Stressproof turned down to 1-1/4" at the machine end. It is used in a 1-1/4" end mill holder, and has two flats, not visible in the photos, for the end-mill holder setscrews.

Click on each image to see it full screen.