Powermatic 66 Bearings

[Jerry Lawrence]

Hi all,
The other day I was ripping some 4 foot X 2" stock of purple heart into strips of varying size, from 1/4 inch down to 1/16 ish, with my Powermatic 66. I noticed that the first 2" or so of the cut was very rough. The blade left chatter marks, for lack of a better way to describe it, like a quarter-circle of snipe basically. I know I'm not describing this very well, but hopefully you get the idea. Anyway, the marks were most prominent in the part of the strip between the fence and the blade...and only on the first couple inches, after that they were perfectly smooth. I tried adjusting the fence, changing blades, checking for square and run-out...but nothing helped. After I had cut awhile, I noticed that the table itself was getting warm, as well as the arbor nut, and assumedly the arbor as well. So I'm figuring the arbor bearings are fried. The saw is at least 25 years old, I have owned it for about 10, and as far as I know still has the original bearings. So...my questions are: 1. would bad bearings cause this "snipe" problem? Like maybe the bearings caused the blade to vibrate, leaving the chatter marks at first, but then once the blade got farther into the wood, it stabalized because of the support the wood provided? And 2. How tough of a job is it to replace said bearings? I found a pair online for $46 delivered, but also a complete bearing/arbor/nut and collar assembly for about $140. Would the complete assembly be the way to go? I'm not above doing a little work to save some money, but I've also attempted plenty jobs where I would have gladly paid an extra $100 to have avoided some very frustrating situations. Anyway, sorry for rambling, and thanks in advance for any and all advice!

[Bill Dufour]

With the saw unplugged raise the blade and grab it. Try to wiggle it side to side and up/down. If you feel any motion the bearings are shot. I do not know that saw but most bearings are easy enough to change. Just be sure the casting is supported right behind where you are pressing. You can often press them in/out with sockets, metal pipe. I have used pvc pipe slit and hoseclamped to get the needed diameter.
Bill

That price seems high for two bearings. I would pull the bearings and match up the numbers check ebay for class 3 or better. With rubber seals not shields.

a little googling yields this:

http://www.sawmillcreek.org/showthre...aw-circa-93-94

http://forums.finewoodworking.com/fi...-powermatic-66

http://www.lexington.woodworkersguil...w%20Manual.pdf

See page 26 of the above link looks like the arbor bearings are both 6204.

Of course I do not guarantee that. best to open it up and check before ordering.


on ebay $6.00 delivered for two
http://www.ebay.com/itm/1-pc-6204-2RS-double-rubber-sealed-ball-bearing-20x-47x-14-mm-/322440075423?hash=item4b12ed189f:g:kV4AAOSw2gxYuIw K

http://www.harborfreight.com/bearing...set-62593.html

[Bill Orbine]

Do you use a blade stabilizer? It will help. And, Are you using a good and sharp blade designed for ripping? I like Ridge Carbide TS2000.... but Forrest makes a good one, too!

[Matt Day]

You can also remove the belts and spin the arbor pulley to see if they sound/feel rough. To do this without taking the top off, raise the motor to give slack to the belts - best way I've found is to go in through the motor cover, raise the blade/motor assembly, loosen the motor mount bolts, and lower it onto a cut to length 2x4; thereby slackening the belts. Then through the blade insert you can remove the belts.

That all being said, usually you'll know bearings are going bad all the noise they make and changes in blade spin down. That'll happen before bearings self destruct causing play. Have you checked the obvious first, like fence/miter slot/blade parallelism?

[Jerry Lawrence]

Thanks for the responses, and the links for the bearings. No, I don't use a blade stabalizer, but I have done this operations literally hundreds of times and this has never happened before. Yes, I was using a brand new ripping blade, the same exact one I've used for years with no problems. Did change blades to see if it was the blade but the problem continued. Yes, I checked for alignment etc. No, I can't feel any noticeable play when I try to wiggle the blade, but if it's not the bearings, then why would the table right above the bearings get hot? Anyone done a bearing swap on this particular saw before?

[Andrew masters]

I have tried a bearing swap on this table saw. I have a powermatic 66 as well. I couldn't get the bearings off, I practically destroyed the shaft trying. I ended up turning around and buying a new shaft with bearings already installed. That's my two cents and my experience. You may have better luck than me but I couldn't figure out how to get the bearings off and back on without destroying parts and wasting money. Keep us updated

[Doug Ladendorf]

25 years it is probably time to change them. It's not difficult but you should have a bearing splitter/puller. When I changed bearings on my 66 I used NSK bearings. If you are going to the trouble do not bother with cheap Chinese bearings and you don't need the whole arbor assembly. In fact it may not be the right length as they changed a bit when going from the three sheave pulley to two sheave. Accurate Bearing is a good place to order if you don't have a bearing shop nearby.

There are a number of threads on OWWM and even a list of threads on vintagemachinery.org. Pull the table, remove belts and pulley, knock the arbor out blade side and change the bearings. Note there are two spacers between the two bearings for the inside and outside rims.

Doug

[David Kumm]

If you go to the trouble get decent bearings like SKF Explorer. A little better precision at ABEC 3. Natchi Quest are similar. For arbor bearings you want standard clearance. Motor bearings will be C3. Bearing supply places often interchange standard ( CN ) and C3 so you need to specify. Sealed last about 20 years so time for change. Dave