This is a question about something that is unimportant but puzzles me. Maybe someone knows the inner workings of the Sherline DC motor and can explain it to me.
I installed a reversing switch on my lathe motor, following the directions on the Sherline website. Basically a DPDT switch that reverses the polarity of the DC current to the motor. Works fine, I do quite a lot of tap and die threading on the lathe. I hold round aluminum stock in an ER collet and do the forward threading by hand, turning the collet chuck with my hand. Sometimes I use the motor in reverse to back the tap or die off for clearing chips from a blind hole or inspecting the external threads. Saves backing off by hand turning the collet chuck in reverse.
What I've experienced is this. If the motor's power switch is off, and the forward/reverse switch is in the forward position, the headstock (collet chuck) is easy to rotate in the forward position but noticably harder to turn by hand in the reverse position. If the switch is in reverse, its the opposite. I thought that maybe something was energized even with the power switch off so I unplugged the lathe. Same relationship. If I rotate the chuck in either direction and I flip the switch back and forth between forward and reverse it follows the same pattern. Maybe there is a charged capacitor flipping something? I let the lathe sit unplugged for 3 days and it still shows the same pattern.
I installed a reversing switch on my lathe motor, following the directions on the Sherline website. Basically a DPDT switch that reverses the polarity of the DC current to the motor. Works fine, I do quite a lot of tap and die threading on the lathe. I hold round aluminum stock in an ER collet and do the forward threading by hand, turning the collet chuck with my hand. Sometimes I use the motor in reverse to back the tap or die off for clearing chips from a blind hole or inspecting the external threads. Saves backing off by hand turning the collet chuck in reverse.
What I've experienced is this. If the motor's power switch is off, and the forward/reverse switch is in the forward position, the headstock (collet chuck) is easy to rotate in the forward position but noticably harder to turn by hand in the reverse position. If the switch is in reverse, its the opposite. I thought that maybe something was energized even with the power switch off so I unplugged the lathe. Same relationship. If I rotate the chuck in either direction and I flip the switch back and forth between forward and reverse it follows the same pattern. Maybe there is a charged capacitor flipping something? I let the lathe sit unplugged for 3 days and it still shows the same pattern.
