Sears Bench grinder

[cstmwgn]

I have an old model Sears 8" 1HP grinder that is getting tired. It will run for a while and then shuts off. As it is coasting down sometimes it will restart other times it just stops spinning. If I turn the switch off and wait a minute (or two) it will start back up and run for awhile. It doesn't matter if it is under heavy load or just free spinning - it just shuts off. Of course there are no parts available from Sears. I have perused the assembly diagram and parts list and don't see anything obvious to me.

Before I tear it apart, I have two potential items to look at
1. Capacitor (I thought that capacitors were generally associated with initial start up - not continuous running)
2. Centrifugal start switch (no clue what this does). Does anyone have any experience with something like this?

Thank you

[2020 mustang]

Are the motor brushes easy to service, replace?

[cstmwgn]

Are the motor brushes easy to service, replace?

I've looked at the parts diagram several times trying to find them and there are none pictured or listed. In the process I have found something they call an "overload switch" which might be an even better culprit as that is what it acts like to me. I have been known to push electric motors to their limits (killed many drills).

I probably should just breakdown and buy a new grinder but if I do that I suspect I am going to buy one with the sanding attachment which puts it over $500.
I guess I could use a stocking stuffer!

[DanStokes]

I love my Woodtech sanding station which is similar to the Delta/Rockwell but cheaper. 12" disc and 6X48" belt. I still have 2 bench grinders with wire brush, grinding wheel, demurring wheel and buffer. You can't have too many tools! As far as you grinder - is it worth taking it to an electric motor shop? Sometimes I call in the pros.

[2020 mustang]

I've looked at the parts diagram several times trying to find them and there are none pictured or listed. In the process I have found something they call an "overload switch" which might be an even better culprit as that is what it acts like to me. I have been known to push electric motors to their limits (killed many drills).

I probably should just breakdown and buy a new grinder but if I do that I suspect I am going to buy one with the sanding attachment which puts it over $500.
I guess I could use a stocking stuffer!

Even if You gift yourself a new one, it be well worth fixing this one, if no other reason as to have wire or buffing wheels on a unit and no need to swap them off.
It has to be something simple , could be the bushings, bearings just need a little grease. or a connection breaking at the switch, and the vibration makes it come and go.
I'm going to assume the power had to pass through the cap at all times, even after start up, so if it is failing, after getting warm, it be like a reostat slowing the units power/speed to a open circuit killing it till it cools.
Mine, A Sear unit bought in the90's has only the plug for the wall outlet, a cap and a basic on/off switch.

[cstmwgn]

... Mine, A Sear unit bought in the90's has only the plug for the wall outlet, a cap and a basic on/off switch.

Yeah, I can't remember exact dates but I believe mine is similar age (late 80s early 90s). And like yours it appears to have the same components.

Thanks for the input.

[cstmwgn]

Well - that is interesting.
Local electric motor repair shop labor rate $100 an hour.
Tear down / estimate charge $100!
I'm guessing unless I can fix it myself without parts that it is waiting to become junk!

[Russell]

If it's as simple as a switch and a cap I am sure you can find replacements. Neither should be expensive.

[2020 mustang]

if it's as simple as a switch and a cap i am sure you can find replacements. Neither should be expensive.

this.