Threading Insert Toolholders Made with Adapter Plate for Previous Fixture
By Ryan Flaherty
I decided to try a couple threading inserts from ENCO. Of course, I needed to make toolholders for them. I realized that my existing fixture for making TNMP toolholders work fine for the threading toolholders if it weren't for the 5* rake set by the Wedge Block. I used the "on edge" inserts, but the fixture should work for the "lay down" type as well.
See my earlier article: Fixture for Milling Ted's Toolholders on your Lathe
Easy enough to fix, just lay out a new Back Plate from 1/2" plate to the same dimensions as the Wedge Block. The hole locations are even the same except that you can lay them all out from one side as all are perpendicular to the plate.
Set up the fixture as before using the Back Plate in place of the Wedge Block, set over 30*. You can "mill in" a helix angle if you wish by setting the compound slide to the desired angle. I used ~ 1 1/2*.
See Photo : Adjust-HA
I cut some end clearance on the blank when I cut it (about 13* seemed to line up w/ the cutting line on insert). Line the insert up on the blank (even w/ top, cutting edge past end) and scribe a line along the back side of insert. Mount the blank in fixture so the line is even w/ bottom of endmill. Remember that you are milling on the side of the toolholder for the "on edge" inserts.
See Photos : Set-up & set-up-1A.
Mill step & mount insert as before. I trimmed the RH edge for more clearance.
See Photos : Toolholders-1 & Toolholders-2.