Powermatic 66 Table Saw Tuning Question

[Timothy Zotta]

Hey guys,

I just bought an older Powermatic 66 table saw (1980) with a 3hp single phase Leeson motor. I am rather pleased with its condition but I have ran into a problem upon reassembling the table. I cannot get the table to "square" up to the blade. Upon further inspection, it appears the arbor is eccentric in the bearing arm. I could ream out the holes on the cabinet to get enough play to make it right but I feel like there is a bigger problem at play here in the bearing arm/arbor. Is this the victim of a poor bearing replacement? Worn out over time? What should I do to make this right? Any help would be very much appreciated. I feel like I got a fair deal on the saw but now I am starting to wonder.............

[Chris Rosenberger]

I have run into this problem a few times when working on cabinet saws.

I am not sure what you mean by the arbor being eccentric in the arm. Are the arbor & bearings tight in the housing?

If the arbor is tight, then loosen the trunnion from the cabinet & see if it will move any.

If I have ruled out any other problems, I have elongated the top mounting holes to get the top & blade alined correctly.

[Timothy Zotta]

The arbor isn't concentric with the hole which holds the arbor/bearings in the arm. The bearings are tight in the arm and don't appear to be worn out. They aren't making any noise but the arbor appears cocked back with the pulley side pulled back towards the motor. Like over time the belts pulled on the arbor and pulled it out of alignment with the hole which would make sense because the table is out of alignment in the same direction the blade is cocked. I'm not sure if the bearings need to be reset in the arm or if I should simply ream out the hole to allow for the proper adjustment. It just seems likes it's out an awfully lo

[Doug Richardson]

I would determine whether I had a bearing or arbor problem, and proceed from there. Is it an actual runout problem with the horizontal or vertical face of the arbor, or is it a shaft mis-alignment with the trunion assembly? Depending on the cost of bearings or a new arbor, and what you paid for the saw, would determine whether it was a fair deal or not. If after repairing it correctly, it does everything you ever wanted it to do, well, only you can determine whether it was a good deal for you or not. I wouldn't, however, start trying to compensate for something that will just get worse(like bearings), by reaming out holes in the cabinet. Like that old cliche goes..... "Do it right, not over.....".

I am not personally experienced with the assembly/dis-assembly of Powermatic table saws..... but I did stay a a Holiday Inn Express last night.....

[Timothy Zotta]

Doug, I feel like the quick fix is to just ream out the wholes but I have never been one for the quick fix for the very same reason you have stated. I'll look into this further. Maybe this will force me to completely restore the saw which wouldn't be such a bad idea either. What I don't to do is do something to fix one problem and then cause another but will certainly look into some of the things you are talking about. At first glance I don't think its a runout problem and more of a shaft mis-alignment with the trunion assembly but I could be wrong.

[Chris Rosenberger]

The arbor isn't concentric with the hole which holds the arbor/bearings in the arm. The bearings are tight in the arm and don't appear to be worn out. They aren't making any noise but the arbor appears cocked back with the pulley side pulled back towards the motor. Like over time the belts pulled on the arbor and pulled it out of alignment with the hole which would make sense because the table is out of alignment in the same direction the blade is cocked. I'm not sure if the bearings need to be reset in the arm or if I should simply ream out the hole to allow for the proper adjustment. It just seems likes it's out an awfully lo

For the arbor to not be straight in the arm, it had to be either a manufacturing defect, the bearings spun in the casting & someone made a poor repair, or the casting has failed & would be cracked.
The only fix is to ream out the holes, find a new arbor bracket or have a machine shop repair the arbor bracket you have.

[Doug Ladendorf]

OK, hang on before anyone does any reaming. If the arm is cracked or worn you may just want to replace it. Keep an eye on eBay or try OWWM.org. Reaming will require re-filling the area or adding a bushing. Have you replaced the bearings? If not, that is the first thing and should be done in any case when picking up a used saw of this vintage. It's not hard but you will need an arbor press, whether yours, a friends or at a machine shop. Typically getting the two bearings and spacer off needs a good bit of pressure, at least to get started. Mine came off with a BANG using a 12 ton shop press from Harbor Freight. Once you get them off read the number on the side and order them. Many of us use Accurate Bearing (no affiliation just a happy customer). Speak to Lynn there. The bearings go on much easier. I was able to do that with my arbor press. You have a quality saw there. You will really enjoy once up and running.
Doug

[Chris Rosenberger]

Doug,

You misunderstood the reaming. We were talking about reaming the top mounting holes, not the arbor bearing hole.

[John McClanahan]

If you loosen the 4 bolts that hold the trunions to the cabinet, can you get any adjustment there?

[Don Jarvie]

Have you taken a look at the manual? That might be a good place to start and follow the setup instructions.

It's probably a good idea to change out the arbor bearings and take it apart for a good cleaning.

[Timothy Zotta]

IMG_0902.1.jpg

Here is a picture of what I'm dealing with. It's hard to tell in the picture but I think you can get the idea.

[Timothy Zotta]

Yes I think I can just not sure that is ultimately the correct way to go about it.

[Timothy Zotta]

I think I have talked myself into a complete dis-assembly and restoration on this saw. Chris's photo of his saw made me jealous. Here's hoping and praying for the best.

[Dave Cav]

I think I have talked myself into a complete dis-assembly and restoration on this saw. Chris's photo of his saw made me jealous. Here's hoping and praying for the best.

As long as you have a reasonable amount of mechanical aptitude and can get the bearings off and back on, you shouldn't have any trouble. Get a copy of the manual from owwm.org (also known as Vintage Machinery) and take your time. A PM 66 is actually easier than a Unisaw as far as I'm concerned.

[Chris Rosenberger]

It looks like a bad machining job. I have not seen an arbor set screw that far off center of the flat spot. Your set screw is at the edge of the flat spot.
That still does not mean that the arbor is out of alignment. The only machining on the arbor bracket is the hole for the arbor, the hole for the pivot shaft & the set screws.
The arbor & the pivot shaft should be parallel to each other.
I have never done this, but a way to check if the arbor is out of alignment is to measure from the center of each end of the arbor to the center of the pivot shaft.
The measurement should be the same on each end. The motor will have to be removed to do this.