I am a french potter's beginner, as I plan to begin my own pottery's activity in 2018. A great teacher I know offered to me an old potter's wheel from 1979 (haha). It is a SEVEN SKILLS Potter's wheel SSB2.
It is a cone drive system, with a pedal/lever you can use with hand or feet. The motor is reversable.
The problem doesn't look so big but it is very important to me as I don't know anything about mechanics and motors. Here it is: when I switch ON, the cone is turning, everything goes ok. When I pull the lever forward to increase the speed, the wheel is turning BUT the lever can't be hold in a moderate position. Either the pedal is pulled forward to the maximum position, or nothing. So I can't really choose the speed of the wheel. I can maintain the pedal to the position I need with my feet, but if I do, the pedal makes a weird vibration and it is quite unconfortable to maintain it manually.
If I reverse the motor (so the wheel turn clockwise), the problem is the same but in the other side: the pedal can't be hold in the maximum speed, it comes back automatically to the point zero, except if I force on it.
So my question is: do you know what is the system that usually holds the pedal/lever in the position choosen, whatever the speed is? 'Cause the problem doesn't seem to come from the motor, or the belt, or the cone..it clearly comes from the pedal but I am unable to identify what is the system failing here.
I join you some photos so if you guys know this kind of cone drive system wheel, maybe you could help me. I would be very grateful, because I am waiting this baby to work to begin my activity.
Thanks a lot!