Our custom grind looks more like a single flute engraving tool (like
this tool from Harvey Tool) instead of a threading insert. I had a tried a few configurations with a thread mill to do it in one shot, tried shimming it either way and also rotating it out of the cut, didn't work out well. We also modified a top-notch threading insert for more clearance on the back, but we started to grind into clamp area of the insert before we gained any improvement in the cut. The custom grind is working very well, nice clean cut and holding up well in production. The grooves only serve to provide traction for your finnger. Thank you for the help!