I picked up a "almost" complete lot of machining tooling for a set of lathes. One item that was missing was a clamp for the tapping head. I reasoned out a quick idea of how it worked and what was missing and did a quick sketch in Fusion and produced a quick part without the outer filet. I also drilled the corners so I wouldn't need to broach the corners. Saying still holds, if you can't find it, make it.
Sometimes I get something I really like and discover a big flaw in it's design. In the following case, my nice shiney new riding mower deck shaft had just given way again. I believe this was the third failure.
The pot metal frame and weak steel direct shaft was a problem and after spending several hundred dollars over the past few years I decided to do something about it. Off to the big shop. After some quick layout in Fusion 360 and a quick 3d print of the housing for test fit, I started work on the shaft while the mill was cutting the housing. I've gotten 2 complete mowings now before fall and it works great. I was pressed for time on this but I did manage to snap a few photos of the new shaft and threading.
I also had to slightly modify a new tool holder I purchased as the ways were too tight for my liking so that took a bit of time to finish up. Now I have a nice shiney new dedicated HSS cut off holder and a mower that won't fail me.