The biggest problems I've been having is trying to stop the machine at the spindle end of the thread and the motor stalling on deep threads. I've read about people using back gears and clutches to make it easier, but my clutch is mounted towards the back so its a pain to get to and I don't have back gears. I didn't think 130 rpm was very fast until I tried to cut a thread 1/2" long. I remembered reading about a spindle crank so I thought I would give it a try. I made the following and it works really well so I figured I would post it in case anyone could use the idea.
The knob has round grooves cut into it for grip. I drilled it through and tapped it 5/16-18. Bought a full thread 5/16-18 bolt from the hardware store, threaded it into the handle and marked what was sticking out the other side. Removed the bolt and chucked it into the lathe. Turned and tapped the opposite end 1/4-20 then turned between the threaded ends to less than the root of the 1/4-20 thread for clearance. Turned a piece of alum round bar to about 1/16" smalled than my spindle bore. (The inside of the spindle is really chewed up from long pieces whipping around inside which is why I went with aluminum and the smaller diam hoping it will deform and bite harder than steel would.) I through drilled it 5/16". Turned a shorter piece to the same diam and tapped it 1/4-20. Milled the ends of both bars to a 30 degree angle to get the wedge shapes.
The wedge idea came from fixing bicycles as a kid. That was the way the neck that holds the handle bars was held into the tube of the bike frame. As you tighten the knob the wedges slide passed each other and squeeze the inside of the bore.
On the end of the longer piece I milled two flats to go into a mating hole on the flat bar to act as a wrench. Spun a bushing for the bearing (which is way to big but all I had) then drilled and tapped the other end of the flat bar for the bearing "handle".
I was very worried about forgetting the handle was in, turning the lathe on and having it swing around and take my head off. My goal was to make it fast and simple to install and remove so I'd me more apt to not walk away from it while it is installed.
The way I made it takes 3/4 of a turn to lock it in and 3/4 of a turn to take it out. No bolts, no tools, no excuse for a trip to the ER
Hopefully this can be useful to somebody else.
Griz