Spindletop

Copyright assigned to the public domain.

Facet I is only 6 deg. If you anticipate problems with chatter, you can rotate the diagram 90 degrees, use a 45 deg adapter and cut step 1 at 39 and 51 deg. You can omit step 2 and 1 and make the cut corners (and central stripe) larger or smaller. You can instead cut fans to pointed corners.