PM66 Arbor issues?

[Chris Fitzpatrick]

Hello all , Hoping to get some help insight into a problem I have. I have a PM66 that's 10 years old. A few months ago I was using a dado blade and heard a noise as if metal had made contact with metal, it only lasted a second. I checked around and could see nothing but the saw sounded a little louder after that. When I put my day to day blade back on I could see it was tight in the ZCI and my after market splitter was not lined up any more. After checking around i found the set screw on the blade arbor was not as tight as it could be, so I tightened up and readjusted the splitter. Recently I noticed the blade was rubbing against the ZCI again, the set screw seemed fine.By this point it must have moved a total close to 1/8". I called Powermatic and a tech told me that any time a blade moves laterally like that it indicates that my arbor bearings were probably going. So I pulled off the top and tried to get the arbor shaft off but the pulley is really tight on there. I removed the two set screws on the pulley, took of the belts, but it doesn't budge. I don't have a pully puller, is that the only way? I tapped it with a rubber hammer around the edges, tried wedging wood in there etc.

Anyway i called Powermatic back and got a different tech who told me that the kind of movement I described would not indicate bearings. He said that the screw that holds the pivot pin in place must be loose or not on the flat spot. So I took the screw out, seemed tight enough and i could see by shining a flash light in the hole that it was on the flat spot and had marked the pivot pin fairly clearly. By that i mean it didn't look like the pin had moved while the screw was touching. So maybe this is not the issue and the arbor is? But I did notice something that I would appreciate feedback on. I've uploaded a picture of the end of the pivot pin. It has two nuts on it and a washer. It is not tight to the casting, should it be? I loosened the outer nut and saw there was a little more left on the thread, but not enough to tighten it up. Another thing which caught my eye was when I lowered the blade all the way , the gap stayed even all the way until the very last turn when I could see the the whole casting get pulled tighter, but when i start to raise the blade it returns to the original position. Maybe it doesn't matter as the blade would be below the table when it would move?

So I'm at a cross road, any thoughts?

Appreciate it,
Chris

[Martin Wasner]

I had a similar problem on both of my 66's. I just used a block of wood to pry it back to where it should be sitting then tightened that set screw. I think it can be a challenge to get it home again, but mine hasn't moved on either saw since.

[Chris Fitzpatrick]

So you felt the arbor shaft with bearings was moving? I heard of someone using threadlock on that set screw.

[Martin Wasner]

We might be talking about different things. Mine was shifting the whole trunnion where it pivots. Sorry for the confusion.

[Chris Fitzpatrick]

So do you think the two nuts and washer on the pivot pin should be tighter against the trunnion than it is in my picture or is it ok to have a gap there? I realize as the trunnion raises and lowers it has to be able to move around the pin. Maybe it's the set screw which is supposed to maintain it's position and the gap makes no difference. Sorry for all the questions, but when you used the block of wood to move it back how did you determine where it should sit?

[John Cole]

I'll be watching this thread, I've had a similar problem with my PM66, although my blade moved after I'd tilted it to 45 and returned it to normal - I just don't tilt it anymore.
Just took a look on my PM66 and that nut and washer are tight against the trunion and it doesn't move when raising or lowering the blade.

[Chris Fitzpatrick]

Thanks John, that helps, I'll check to make sure the other side has the snap ring in place and add a few washers to the side with the nuts. Or maybe I should just loosen the set screw and knock it over till it's tight on that side.

[Chris Fitzpatrick]

Has anyone ever removed the pulley on that saw? I'm thinking of changing the bearings anyway as they are a bit noisy . That pulley is on tight and there is not a lot of room between the arbor end and the side of the cabinet. Do they make pulley pullers that small to fit in there? Never used one before.

[Martin Wasner]

So do you think the two nuts and washer on the pivot pin should be tighter against the trunnion than it is in my picture or is it ok to have a gap there? I realize as the trunnion raises and lowers it has to be able to move around the pin. Maybe it's the set screw which is supposed to maintain it's position and the gap makes no difference. Sorry for all the questions, but when you used the block of wood to move it back how did you determine where it should sit?

I'm a little hazy, but I think the big nut in there is just a keeper really and it bottoms out. I can't remember for certain.

When I was moving the trunnion around, I think I used the bolt to find center. Wiggle, tighten, wiggle, tighten, until I thought it was home.

It's been probably four years since I've had to do anything other than routine maintenance to either saw.

[Martin Wasner]

For whatever reason, I can't see attached pictures with my phone and I'm rarely on here on a computer.

[Chris Fitzpatrick]

Well I took off the motor to get a good look at the pivot pin snap ring, it was in place and the set screw was tight on the pivot pin but there was a lot of slack in the side to side movement , about 3/32. When everything was tightened up I could move it side to side. I should have tried to do this at the start. Anyway I took off the nuts that were locking it and inserted a nylon washer. When I tightened it all up it was nice and snug. It must have been like that from new, can't imagine why I'm only seeing the effects now. Unless maybe the bearings in the arbor contributed somehow. Anyway I'm going to do the arbor bearings now too since I have it apart and they sound a bit rough. Got the pulley off, what a job, I've never seen anything that tight. Now the woodruff key is in there tight too, like it's welded. I'll try a vise grip and hammer to tap it out, don't want to damage it. Powermatic says they sell the whole arbor with bearings installed now rather than bearings separately. Looking forward to getting my saw back, I have to say I really love it and it never gave a bit of bother for 10 years.