Shopsmith Forums

Thank You for the additional pix.

Please verify the last set were with the OEM belt.

If so I am left with one more thing to check.

Everything appears 'normal' so check the position of the fan sheave on the motor shaft. It should be pushed towards the motor as far as it will go. There should be a spacer(non-visible essentially) that prevents the sheave from actually contacting the motor. It is VERY close.

I’m still working on the spacer question but meanwhile-
yes, that picture was taken with the oem belt.

Also, this is a pic of the nut on the end of the motor shaft. Based on the amount of the protruding shaft, is the nut too tight? If the protrusion was less there would be slightly more room for the sheaves to expand. Dangers?

And, what would be the pros and cons of milling 1/4” off the front end of that stub on the motor sheave? Just thinking.

Still working on getting the sheaves off to look at that spacer.

Been awhile since I did fastener inspections but IIRC, minimum of one full thread should be exposed after tightening a regular fastener or flush with a nylock fastener. There is one thread exposed as shown in your picture so I would not loosen it any.

I believe the nut should be tightened until it bottoms out. BTW it is a left hand thread.

I really would like to see a pix of the fan sheave and the motor end cap(bell). That would either confirm or deny my suspicion of the improper position of the sheave on the motor shaft. At this point that suspicion is all I have to explain thy experience.

As an FYI I had the motor open when I rebuilt it to clean it out and to replace the bearings. I may not get the pictures until after the holiday. I have to make a spring board to remove the spring.

oddie wrote:As an FYI I had the motor open when I rebuilt it to clean it out and to replace the bearings. I may not get the pictures until after the holiday. I have to make a spring board to remove the spring.

That makes my suspicion stronger.

IF the fan sheave is not positioned on the motor shaft correctly, it should be possible to correct that without removing the spring etc.. Assumes no burrs etc..

Thanksgiving is over, back to work. To verify the spacer was grounded against the motor bearing I had to take the machine apart. I have a 3/4hp A O Smith motor. The only access to the Allen screw that secures the fan sheave to the motor shaft is on the side of the motor that faces the motor pan. So I had to take the motor out. On initial inspection it appeared the spacer was grounded. But I reseated the spacer and the sheaves anyway. Both before and after the reseating there was a very small, less than 1/16”(?), of in/out movement of the motor shaft.

With the original OEM belt installed I plugged in and ran the machine. It runs but at an even faster speed. And the speed control binds at “D”.

Something I have not mentioned because I don’t see any relation to my problem- I’ve wired this motor to run both forward and reverse. Have not had any issues with running in either direction. Except it runs fast and the speed controller binds at slow speeds.

Your thoughts?

oddie wrote:Thanksgiving is over, back to work. To verify the spacer was grounded against the motor bearing I had to take the machine apart. I have a 3/4hp A O Smith motor. The only access to the Allen screw that secures the fan sheave to the motor shaft is on the side of the motor that faces the motor pan. So I had to take the motor out. On initial inspection it appeared the spacer was grounded.
7E55058F-D881-43AE-A26E-516FF83B415F.jpeg
But I reseated the spacer and the sheaves anyway. Both before and after the reseating there was a very small, less than 1/16”(?), of in/out movement of the motor shaft.

With the original OEM belt installed I plugged in and ran the machine. It runs but at an even faster speed. And the speed control binds at “D”.

Something I have not mentioned because I don’t see any relation to my problem- I’ve wired this motor to run both forward and reverse. Have not had any issues with running in either direction. Except it runs fast and the speed controller binds at slow speeds.

Your thoughts?

Well so much for THAT theory!

Obviously from that pix, the floating sheave is closing fully against the fan sheave.

Refresh my memory re how the speed control 'stops' at D.

You cannot turn the dial any further?

The belt starts slipping(on which pulley).

I do not think internal wiring changes were anything to cause this unless reassembly introduced something(which has not become apparent either).

BTW there should have been a small access hole in the bottom of the motor pan.

I think maybe we need to go back up and closely examine the idler shaft pulley. I am now suspicious of the positioning of the idler sheave on the idler shaft.

Referring to the small access hole in the motor case, “small” is the operative word. We couldn’t see or feel anything when looking for the set screw so we didn’t bother with it. So we bothered with tearing it down.

The speed controller stops at “D” because the stub of the motor sheave grounds out at the nut on the end of the motor shaft. There’s no more room for the motor sheave to move to allow the sheaves to open to allow the belt to move closer to the center to produce a slower speed. Not to sure where to go from here. I can stop now or continue with a fix.

This machine is a shorty (original owner did it) and I use it as a sanding station with the belt sander on one end and the strip sander on the other. I can mount the disk sander and table when necessary. It’s too short to have everything mounted at once. So I don’t really need the very low end of the speed range. But I do need to slow this thing down. While I don’t need the lower end for my work, if I stop trying to fix it here, there remains an unsolved problem.

I’ve asked before - what are the pros and cons of milling 1/4” or so off the end of the stub of the motor sheave? If done there would be more space for these sheaves to open allowing for a slower speed.

For the record these are pics of the quadrant taken from under it (camera laying on the motor). The text on the pic shows “Fast” and “D” positions.

Hokay!

I think we have determined the motor shaft stuff is behaving correctly. No I do not think modifying any of those parts will be the correct action to undertake.

Move our attention to the idler pulley.

I will continue this after reviewing this entire thread.