(04-09-2012, 12:48 AM)Mayhem Wrote: Dave - I'm curious to why you used a threading insert to only cut 60% of the thread and then finished it with a die?
Nice work on the cutter. Have you tried it in steel?
Mayhem,
60% thread (depth) it may have been only 50%, my arm was getting tired.
Because the thread length is short I decided to turn the chuck by hand. Under power by the time I have started it would have been time to stop and not having a brake to stop it very quickly and not much of undercut/run out a little risky.
I think the lowest speed is about 80rpm, without changing to the slower pulley sizes. I'm far too lazy to change to the slower pulleys for just one thread.
So my left arm/hand provided the power. Once it is at 50% I know there is little chance of the thread wandering whist using the die. Also I don't have to measure the thread, the die will take care of that.
The main reason I start the thread is to make sure the finished thread doesn't wander.
If I have to cut a 6mm thread by 40mm long I will use this method again to keep the finished thread straight.
I have used it on steel, it worked fine - it is an carbide insert so one would expect it to work. I just reduced the depth of cut.
DaveH