Belt sander throwing sparks

[Jeff Atnip]

I inherited my Dad's Milwaukee 4 x 24 Belt sander. Model 5936. After I replaced the old cord, it works fine, but it is throwing sparks out the front over the top of the belt. The sparks start coming before I contact the wood to be sanded.

Before I take it apart, does anyone have any general thoughts about what to look for? Thank you.

[Rob Cunningham]

Could be the sanding belt not tracking properly and biting into the housing. Is there a tracking adjustment knob?

[Jeff Atnip]

Thanks. I believe there is a tracking adjustment knob, but the belt appears to be tracking true and straight. The sparks are coming from the middle top inside and not from the sides.

[Bob Vallaster]

Good that you have some notion of where the sparks are issuing.
Don't run it again until you have found a problem and attempted a remedy.
Is the belt tension adequate to take out slack, so the belt doesn't crown going over the top?
I would remove the belt, vacuum or blow out the dust in the return path of the belt, then use a pen light to look into that area for something metallic (probably steel) that is being kissed by the passing belt.
Good luck. That's a handy tool to have.

BobV

[Chip Lindley]

Metal is being contacted somewhere along the top of the belt. The belt slips on from the side, so you should be able to see anything interferring with the belt rotation. Otherwise, disassembly may be required to get to the root of the problem. Then you can see where the wear is happening to metal parts from the belt. Just keep all your screws etc. in a tray in one place. If you get lost, I am sure parts diagrams are available online for your Milwaukee model number. Just do a Google search. Good Luck!!

[Michael Wildt]

Have you tried to run the sander without the belt mounted ? Just wondering if it is the internal coal sticks that is transferring power to the motor you see spark. Very common to see on a drill, through the venting holes.

Tip
If you decide to take it apart further then, if you have a digital camera, you can document how it is put together. Just in case you are uncomfortable on taking it apart.

Tip 2
Sometimes you can find exploded part diagrams of the tool in the manual that can help in how it was put together.

Michael

[Jeff Atnip]

Thanks to everyone for your responses. This gives me a lot of good ideas and confidence that I can fix this. I was amazed to look this model up on Amazon and see that it was selling for $339.00! So I guess it is worth it to try and get it running right.

[Dick Strauss]

Maybe you've got worn out brushes bottoming out?