Threading on Sherline lathe
2 Leadshine em 705 stepper controllers
1 Pmdx 122 Bob
Omron quad. Encoder and channels
Parport built in that does spp, epp, ECP
Dayton 2m139 spindle motor
2 AMT dual shaft 156 oz-in stepper motors.
First question is do I have everything I need or is a vfd needed?
If so what will work with this motor? It is 165 watts.
Have a look here: forum.linuxcnc.org/26-turning/30181-sher...rsion?start=20#86760
4tpi on a Sherline seems ambitious. Are you sure that the Z axis can move fast enough to follow a 4TPI thread at the selected spindle speed?
Boltonbrass wrote: Not sure if it is able to do 4 tpi. For what I am doing I have to have 40 tpi internally and externally. I tried threading again, and I set the spindle speed at roughly 1000 rpm. The tool engaged engaged the part at the same speed it jogged to the part from the home position. It simply is not synching up to spindle.
Max velocity in the INI file is 0.475 in/sec.
40 tpi @ 1000 rpm = 0.417 in/sec.
So the machine should be able to do 40 tpi @ 1000 rpm. How accurate is your spindle speed? It would not have to be much faster than commanded for the system to be unable to keep up.
It might be that the Z-axis can never actually "catch" the commanded position.
My slowest rpm is basically 1300 so I will have to change motors, so I believe I am good to go. You are a real trooper and I thank you for your help.