Shopsmith Forums

I’m having trouble with my power head.

I turned a couple pens about 6 weeks ago, and everything was ok. 2 weeks ago, I went to use the table saw, and it wouldn’t go up to speed. It would go partway up and loose speed and power, maybe ever wooble a little.

Every few days, now I’ve been running the speed up and down to see if I could work it loose.

Today I opened it up and gave it 6 drops in the lower hole. And 6 in the upper. I ran it up in speed and down a few times.

It behaved better, however, the upper pulley doesn’t seem to be opening up as it should, or the belt isn’t dropping in all the way. About 3/4 of the way to fast, the belt starts flapping around and it looses speed and power.

You are looking at the wrong pulley for the cause of the problem.

The lower pulley(on the motor shaft) it what provides belt tension.

The floating sheave is sticking.

6 drops is just plain stingy and typically insufficient.

Getting oil into the 'oil hole' in the floating sheave is dicey at best.

Applying oil directly onto the shaft with the pulley closed(fast) will get oil to where it needs to be. Then raise to vertical overnight(or longer) to allow the oil to seep further onto the shaft.

When adequately lubricated you should be able to move the floating sheave out by pulling. You have to overcome the spring tension, but it can be moved manually.

DO NOT LET THE SHEAVE SLIP AND BANG CLOSED.(less of a problem with the belt in place)

While you are at it check, clean and lubricate the gears on the back side of the speed control.

After an additional 12 drops in each hole. And leaving the machine upright in drill press mode for 2 weeks, the speed is more responsive. The speed file is still hard to turn down, the screw and gears inside were cleaned and brushed with a brass brush when I oiled it both times.

I think a motor bearing maybe going as there is high pitched wine coming from the motor.

When you get a second, measure the width if the drive belt. 1/2” or less may mean that the belt has worn and is so narrow that it drops too deeply into the pulley at either extreme of the speed range and binds.

One way to help see if this is in play is to raise speed to just below full and just above slow which will keep the pulleys from opening all the way at either range. If the problem only manifests itself at the limits, then suspect a worn belt.

It worked for a while, then I noticed with the covers off, when I tried to increase speed, the belt on the sheaves became floppie. One sheave wasn’t moving freely.

I watched, and noted that when speed was increases, the sheaves on the motor, didn’t respond right away, and VERY slowly opened but the belt remained loose.

On one of the YouTube video, on repairing the headstock the host suggested adding a drop or two of penetrating oil (NOT WD40) to the motor oil hole.

This helped somewhat but speed changes were only accomplished very slowly, and the belt was still very loosest high, but tight to specs at slow.

While running the speed up and down, I noticed that I could see the offset in the sheave parts through the spring at high speed. This gave me an idea. I put penetrating oil (NOT WD40) on this offset by opening the space in the springs as you would do when oiling, but between these parts.

When I turned it on 10 minutes later, it sprayed oil, but the speed change was MUCH easier, and the belt now remains tight.

I’m now nervous that maybe I shouldn’t have put the oil there, but disassembled the headstock, and cleaned the motor sheaves.

Belts are on the way, anyway, this is a 1986 510, and I have never changed the belts as they look new, and measure to spec.

Drive belt measures 1/2”.

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