lathe motor trouble

[sadbadger]

hello...i have a watch-craft motor...i recently took it apart and cleaned it,changed the brushes,in order to fix a problem that i have been having with it..when it runs it runs fine but just some times it just does not work...i have to play with the forward and reverse switch in order to get it to run and now it only runs in one direction and even for that to happen i have to play with the switch...im assuming that i need to replace the switch...i was wondering if anyone had a similar problem or if they did where would they go to fix it..how much do you think it will cost to replace the switch??id rather not get a new motor but if i did id like to replace it with a more powerful motor but i dont know what kind of motor i currently have so i dont know what would be a step up..thanks for any advise you guys might have

[sadbadger]

hello...i have a watch-craft motor...i recently took it apart and cleaned it,changed the brushes,in order to fix a problem that i have been having with it..when it runs it runs fine but just some times it just does not work...i have to play with the forward and reverse switch in order to get it to run and now it only runs in one direction and even for that to happen i have to play with the switch...im assuming that i need to replace the switch...i was wondering if anyone had a similar problem or if they did where would they go to fix it..how much do you think it will cost to replace the switch??id rather not get a new motor but if i did id like to replace it with a more powerful motor but i dont know what kind of motor i currently have so i dont know what would be a step up..thanks for any advise you guys might have

[Smudgy]

I think the watchcraft motor is a 1/5 horsepower motor, but I'm not positive. It should be listed on the medallion along with the voltage, amperage, and the watchcraft name. It's basically a sewing machine motor.

[sadbadger]

yea i figured it was between a 1/4 to a 3/4 hp motor but on the label mine says 110hp...i know that this cant be possible but i swear that mine has 110 stamped by the manufacturer...the first 1 is a tiny bit higher than the 10 but it seems to say 110 hp..i was wondering if anyone elses watchcraft says this or is mine just a misprint

[4thdimension]

Hi, Perhaps it's 1-10th H.P..
-Cort

[Gnomon]

The Watch-Craft lathe motors are typically 1/10th HP. The rating is at some very high speed like 10,000 to 20,000 rpm. In typical watch lathe use, they run from 200 to 2000 rpm, so they are running well below their nameplate HP. A variac (variable autotransformer) will give you more torque at low speeds, than will the usual sewing machine foot pedal (rheostat). It will run cooler too. (though the motor will run hotter)

Replacing the reversing switch is fairly easy. You will have to completely disassemble the motor. Be warned that the wires leading up to the switch are the fine "hair wires" that come from the field windings.

Using a bigger motor is probably not a good idea. The O-ring belts cannot transmit very much torque when they are operating at tension that is safe for the cone spindle bearings of your lathe.

Note: Proper tension for your belt is when any looser would allow the belt to "arc-up" at the motor's pulley when not running. (eg. the belt is just tight enough so that it is flat from the motor pulley to the lathe pulley.) Always release the belt tension whenever you walk away from your lathe. Always rotate the spindle a bit, without belt tension before you start to use your lathe. This distributes the oil you always add to the spindle before a day's use.

-Chuck Harris

[sadbadger]

HEY CHUCK...thanks for the advise...i began to follow your instructions but then saw that in order to remove the reverse switch you had to disconnect the wires and resolder them to the area near the brushes..this seemed a bit much for my limited motor knowledge/tooling so i decided to go another route....i totally reasembled the motor and from the outside of the motor /outside of the switch you can see a pin holding the actual ball of the switch inside of the socket that it swings in..if you use a tiny punch ,you can remove this pin and remove the ball(part of the switch you flip with your finger)after removing this and studying the components/springs and such inside the switch..i noticed some of the contacts inside were dirty and rusty so i cleaned off the corrosion and reassembled the switch..after doing this the switch again works like new...the best part about this was i was able to do all this without opening the motor at all...well at least i would have been able to if i thought of this solution in the first place..ha ha ..anyway just wanted to post my solution incase anyone else ran into a reverse switch problem with their motor

[Gnomon]

Hi sadbadger,

I've done that before too, but it is a bit like playing gynocologist with the switch. I find that I can do a better job if I remove the switch. If you loosen the nut on the switch, and remove the brushes, and the caps that hold the brush holders, you can pull the can off of the back of the motor with all of the connections intact... Atleast I recall doing something like that... I'm not sure if it was this motor, or another. It is unusual for a manufacturer to make its worker's lives too difficult...difficult costs time and time costs money.

Anyway you get there (without butchering things, that is) is fine. I'm glad you found a good way to fix the problem.

-Chuck Harris