Yesterday I started making a Draw Bar. I have been thinking of this for several years and designed it a couple years ago so it feels really good to kick this off. I'll start a dedicated thread in the projects section to document it, but I wanted to post some pictures of tonight's action... internal threading!
I started off by creating an external M30 thread, to work out the bugs with the setup and also to have a thread checker for the internal thread. After I made the external thread and got most of the way into the internal thread, I was having difficulty getting the parts threaded together, they were very tight even though I had removed what I thought was enough from the internal thread. I remeasured the external thread and the major diameter was too high, so I must have initially measured that wrong. I took the risk and removed the draw bar, losing the threading setup, put the externally threaded piece back in and hit the major diameter, then re-acquired the thread and brought the pitch diameter down to what looked right and fit with the draw bar. A bit nerve racking but it worked out well.
Cutting the internal threads. I used a piece of tape wrapped around the draw bar to tell me how deep to cut before shutting off the lathe.
Setup:
Looks decent
And works well
Gotta say I'm pretty excited about this.