Help with Jet 22”!

[Pastortim]

My Jet 22” scroll saw started sputtering mid cut. It’s like something was holding back. I thought it might have been the speed control switch or circuit board so I put new ones in it. It’s still doing the same thing with the new parts. When I push the foot switch nothing happens but if I push the lower jaw with my hand a little it will start going but still acts like something is holding it back. It will make a few strokes then stop. I’ve cleaned and blown out every crevice but still nothing. It’s only about 4 years old but I looked over the brushes anyway. Could the motor be shot?  I’m at a total loss. 

[Scrappile]

Have you tried it without the footswitch?  Just a thought.  If it has brushes and they wear out, it is an easy fix, if you can get replacement brushes.

[Wichman]

Page 17 of the manual shows how to check the brushes and commutator for wear. Your description fits worn brushes, so that's where I would start.

[OCtoolguy]

Try it without the foot switch. Eliminate that possibility.

[Pastortim]

Yes, I tried it without the foot switch and I checked both brushes. Hopefully it’s not the motor but I’ve checked everything else I know to check. 

[Wichman]

Did you check the commutator? That's the part that the brushes ride against. When you remove the brushes you can shine a light down the hole, you should see bright copper bars with spaces between them. Slowly rotate the motor to see if there's any damage or a piece of debris shorting two or more of the bars.  I've had to take a motor apart and use a Dremel tool to clean out the spaces (metal fouling), then reassemble.

With the brushes, did you check to see if they have a "glaze" on the face on the commutator side? That face should not be shiny, but rather a dull finish  

[Pastortim]

7 minutes ago, Wichman said:

Did you check the commutator? That's the part that the brushes ride against. When you remove the brushes you can shine a light down the hole, you should see bright copper bars with spaces between them. Slowly rotate the motor to see if there's any damage or a piece of debris shorting two or more of the bars.  I've had to take a motor apart and use a Dremel tool to clean out the spaces (metal fouling), then reassemble.

With the brushes, did you check to see if they have a "glaze" on the face on the commutator side? That face should not be shiny, but rather a dull finish  

I didn’t check that. The brushes didn’t look like they had any fouling on them but the top was as shiny as the sides. Definitely not a dull finish. I will check that next and see. 

[JTTHECLOCKMAN]

Take some emery cloth and form it so you can fit in brush hole and spin the motor by hand. You should see nice copper color when done. Use a fine grit. Do not use sandpaper. Just a quick pass or two is all that is needed. They do make commutator stones for cleaning and setting brushes too. May have to cut to fit the hole. Also a quick pass or 2 on the brush to take the glaze off it. When installing brushes make sure you mark the brush the exact way you took it out and put back the same way. Also make sure the spring has enough tension to keep brush riding on commutator. 

Edited June 13, 2025 by JTTHECLOCKMAN