Powermatic 66 Arbor Bearings

Need to replace my bearings. Stamped with NTN 62304ZZA, powermatic part # 6060009. Anything special about these bearings? Can pick up matching bearings from NAPA auto parts if there is nothing unique about the powermatic bearings. Any cautions or suggestions about replacing the arbor bearings?
Thanks MB
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wrote:

I'd look in your yellow pages for a bearing supplier. the cost may be less than a car parts store, the folks there will have more knowledge about bearings and more information to cross reference from. automotive bearings may not have the right PRM ratings or shielding, for instance.
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wrote:

When I replaced the bearings in my 66 recently the local bearing store had them in stock. Everything is a tight fit so you will need a press or puller to do the job. With a gear puller and some imagination the job can be done. I bought a couple of bushings for the puller to pull the bearings back onto the arbor with, so the force would be on the inner race of the bearing. The arbor assembly is a snug fit in the whatever it's called that holds it. I put the rebuilt arbor in the freezer and heated the arbor holder with a heat gun to slip it in there. I replaced the bearings in the motor at the same time and everything was just under $50.00. It was about a 6 hour job for me but that's also the motor rebuild and cleaning everything up along the way. If you don't have a book with a parts drawing, a copy can be downloaded from Powermatic. It will help when it's time to reasembly the arbor. Or if you make notes that would help. DAMHIKT
-- John, in Minnesota
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John:
Thanks for the infor. How did you get by so cheep? My saw has 2 of the NTN 62304ZZA bearings. They sell for about $65.00 each. Have downloaded the Powermatic 66 Owners Manual from Powermatic. Also have downloaded a parts price list and a service manual from the "Old Wood Working Machines" web site, www.owwm.com.
MikeB

#
arbor
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wrote:

I looked for the receipt or 1 of the old bearings but can't find either one right now. But, I believe the bearings on my saw were 6204zz's. (it's highlighted in my Grainger catalog) A 20mm bore instead of 17mm on yours. I can't imagine Powermatic changing something on the 66 in the last hundred years, but maybe. 6204zz are about $10.00 each. On the recommendation of the bearing shop I used 6204LLB's or LLU's which have a better dust seal than the ZZ. Only a couple bucks more each. I've read somewhere that the first 2 digits of the saws s/n indicate the year of birth. If so, mine was born in 1981. Is yours about the same vintage? New bearings in the saw & motor made this baby run like new. Smoooooooth.
-- John, in Minnesota
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My bearing measurements are probably the same as yours, 20mm bore, 47mm OD and 20.5mm width. I am guessing, but I think the 63204ZZA may have a higher temp rated grease?? Seem to get this indication from the NTN web site. Unsure of the age of my saw, serial # is 266845. But in the right light and a little spit it could be 2266845. Looked at the serial number sequence key in the Powermatic section of OWWM. Can't fit my serial number into this scheme. What is your serial number?
Mike B

NTN
parts
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See another difference. According to NTN the 6204 bearing is 14mm wide and my bearings 63204 are 20.5mm wide. If I were to use the narrower bearings I would have to order new spacers and spring ring etc. Have to bite the bullet and order the more expensive bearings.
Mike B

the
the
web
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fwiw I've done the bearing replacement on two PM66's, an '88 and a '71. Bought both as basket cases and kept the 72 because it's nicer and the top was straight. Replacement is pretty simple and straight forward
Both machines had identical arbors, bearings, spacers and housing. Later machines have different pully drive (3vx two belt rather than original three belt).
Bearings removed from both where marked NTN 62304ZZA and original on both I think. Double row and plastic sealed both sides. Powermatic had them for $44 ea. Napa and a bearing house had them for $36 when I checked a few years back, - but - the napa part had a different seal arrangement with the race visible on one side although it was a double row 62304. So check it before buying. In the end, for both machines I bought the PM bearings at the same time as a few other parts needed.
I don't know about others experience but in mine I'd say this; If not using original spec bearings still use the correct width, full size double row bearing, It's important in both fitting straight, locating the spindle and I think, to provide the necessary support and accuracy while running.
The bearing fit was *tight* so I think some kind of press is needed. I first tried putting it together on the cheap with a few tubes and a mallet. It went together with some effort, with difficulty getting it aligned straight and in the end also ran with some runout. No explaination why but it wasn't right.
Next try I used a cheap HF hydralic press to mount the bearings on the spindle and it aligned and installed fine. More importantly with no runout. Note according to powermatic the bearings are pressed on the arbor first and then the spindle, bearing, spacer assembly pressed into the housing. That means that one bearing is pressed into the housing by it's center rather than, more correctly, by the outer race. You can knock the assembly in with a mallet but its kinder to the bearing to press it I think.
Next time around on the second machine it took about an hour to remove old bearings, fit new and replace, way longer to strip and replace the trunnion. You could do it with trunnion in place but I had to clean it up and replace some of the collars anyways.
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My saw has 3vx pulleys. Need 3 belts or get by with 2?

I
the
62304ZZA ? or 63204ZZA? NTN does not show a 62304 and does not show a 63204ZZA. The do show a 63204ZZ/2A. Their listing shows the bearing as a "Single Row Deep Grove" bearing with steel shields on each side (ZZ). I assume the "A" referred to the bearings grease. "2A is shell Alvania #2. Must be high speed grease. No one had the bearings, or equivelant, in stock so I ordered from PowerMatic.

as
using
mallet.
runout.
My arbor assembly came out real easily. Just some light tapping. Hope the new bearings will go in as easily. Have allready dis-assembled, cleaned and re-assembled the trunion so will try the Hot - Cold technique to ease the installation of the arbor assembly.
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AFAIK older pm66 saws had three belt pully drives, newer model (eighty something on) had the 3VX system which confusingly is a two belt system. If it's 3VX the pullys are two groove only.
I ran my 'old' saw as three belt and then upgraded to two belt when I replaced the motor, the new motor had a 5/8th arbor, the old 3ph motor I was replacing was a 3/4" and no 5/8th three belt pullys were available at a reasonable price. new 5hp motor and 3vx belt is very smooth and I've not had to adjust it since installing.

Hum, I've dug out the old bearings in the box of spare PM66 parts, never threw them out. Im pretty sure that under the rust they 62304 ZZA, maybe one of the Z's is a 2, but they definitely are two row plastic sealed bearings approx 47m od, 20.5mm deep, 20mm bore.

If the assembly came out easily then I think you'll have great sucess reassembling with a bit of heat/cold and some light persuasion. I had to put some effort into it because my assebly, carrier fit was incredibly tight.
A trick to watch when putting the assembly in is to consider the arbor blade flange location and get it located centrally in the table slot first, while still allowing the lock screw to locate the arbor and then line up the motor drive pullys.
have fun..
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GOOD GRIEF, do you really mean you pulled them into the arbor using the ID?? That's crushing the balls and dimpling the outer race! Hopefully they weren't very tight. Or maybe you meant "not on the inner race"? One should never put any side load on a bearing. You could use your same rig with a big socket pushing against the outer race, but maybe that's the bushing you mentioned? Wilson

#
arbor
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wrote:

Probally was'nt too clear on that. Yup, that's when I used the bushing resting on the inner race to pull it back "onto" the saw arbor. Rebuilt the arbor first then slid it back into the saw. No side force on the actual bearings was applied.
-- John, in Minnesota
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