Black powder gunk under motor?

[coldje]

I purchased a 1982 Model 500 and intend to rebuild the headstock. I got the headstock off the frame and the guard off.
I detached the motor from the bottom casing and the casing was full of saw dust. There was some black powdery gunk directly underneath the motor. It didn't smell burnt. There was also two little metal round pieces that look like they were fasteners once. Has anyone seen this before and knows what it is?

[RFGuy]

Bits of a burnt up belt in the past?

[DLB]

First, welcome to the forum. If the motor is running and it doesn't smell burnt my first guess would be some form of damage to the V-Belt (lower) or PolyV (upper) Belt. Several possible causes, but a visual inspection of the belts would confirm or eliminate. The V-Belt should be 1/2" across at the wide part of the "V."

Note - there might not be a problem. As you've noted, the headstock collects a lot of sawdust. It can also collect other materials if it is being used for something other than woodworking. And they often get mixed with whatever is used for lubricant, especially if over-lubricated. The headstock is forced-air cooled, it pulls in whatever is in the air around it and some of that collects. Dust collection helps a lot, but the only thing that eliminates accumulations is taking it apart and cleaning it.

I didn't see the metal pieces in the pic. Based on experience, I would look at the button bearing on the Control Sheave, especially the wire loop and spring tension pin used to connect the Control Sheave to the Speed Control. These can fail for a couple of reasons. We can talk about those reasons if you confirm. We've also seen cases where these parts were intact but also laying in the bottom of the motor pan, basically a failure that has been repaired.

Good luck!

I see RFGuy beat me to the punch and is also thinking belt.

- David

[rpd]

I am thinking belt too.
The only other thing would be if the insulation on the power cord was chafing on the sheaves, but there looks to be more debris than that would account for.

[chapmanruss]

As suggested it may be an accumulation of several things. Some belt wear and of course dust would be common. From it's location at the bottom of the Headstock it could be both collecting there and heated from the motor running to the point of charring but not quite enough to actually burn. How does the motor surface there look? Dust accumulation can cause the motor to overheat during operation. Clean it out, service/lubricate the headstock parts and if the motor is working fine and the belts look good go ahead and use it but check on it regularly for a while to see if it continues. As for the "fasteners" it is hard to tell from your picture what it might have been.

[JPG]

I think the black stuff is located at the wrong end of the motor pan to be belt debris. There also appears to have been some liquid flow. Is the black paint on the motor intact? Is the black stuff sawdust that has been blackened somehow? is the external paint normal or does it appear to have been heated? Sorry more questions and no 'answers'.

[coldje]

I like the bad belt line of thought. The belts looks pretty new. Perhaps they failed in the past and were replaced?
Another issue could be some liquid that dripped into the motor pan. There was varnish or some liquid drip stains on the skirts bad enough that I sanded and repainted them. Perhaps a previously owner got overzealous with varnish?

Thank you for the button bearing idea. The speed dial does seem a little crooked, like tilted. I'll get into that soon and let you know.

Jeff