pm66 arbor question

[ken carroll]

The saga continues on the pm-66.....

From my other recent thread on my "new" pm66 you'll notice that I had a three groove pulley fitted on the saw, at first I thought that someone had swapped the two groove pulleys out for three grooves so that they could get belts locally or something like that. As I've learned more about the saw I now think that the issue is that someone has replaced the arbor bearings and either not pressed them in far enough or used the wrong width bearings. Because of that the three grooves on both pulleys didn't line up so they simply lived with the offset of the two pulleys by fitting two belts instead of three!

It's clear from the condition of the beat up zero clearance insert I got with the saw that the saw is shifted towards the center of the throat plate from where it should be.
http://www.sawmillcreek.org/attachment.php?attachmentid=165313&stc=1&d=1287903084

You can see where the blade completely misses the starter kerf in the insert.

Whether the bearings have not been pressed all the way in or whether they are the wrong bearings I am not sure but I can see the number on one of the arbor bearings -it's a 6204 type which I believe is the earlier bearing which I think is correct for a 91 saw. Is it? Am I?

Front side of arbor showing bearing slightly "proud" of surface
http://www.sawmillcreek.org/attachment.php?attachmentid=165315&stc=1&d=1287903488


Back side of arbor showing bearing very recessed
http://www.sawmillcreek.org/attachment.php?attachmentid=165316&stc=1&d=1287903488

Here's the motor pulley. Is this correct? The pulley is taller than the motor shaft is long. Works but seems unusual.

http://www.sawmillcreek.org/attachment.php?attachmentid=165317&stc=1&d=1287903488

How does this look versus your perfect never screwed with PM-66?

ken

[Carroll Courtney]

Ken,if it was me I would start all over on the arbor.Take it apart and press in new bearings which should come w/new retainer rings that will hold them in place inside the arbor housing.Piece of mine is worth alot,but also go to www.owwm.org (http://www.owwm.org) then go to wiki section and you should fine info on the arbor.-----Carroll

[Chris Rosenberger]

It is difficult to tell a lot from the picture angles.
I will try to help. I have restored several PM 66s & used them for several years, but I currently do not own or use one.
I do not think the arbor has the wrong bearings. That is a newer style arbor & it looks like the bearing is against the snap ring. The arbor can be side to side.

The final setting of the arbor needs to be made with the table mounted & aligned with the blade. I would set the blade location to a stock insert. Since I do not have a saw or insert, I do not have that measurement. Maybe someone that has a PM66 can get you the measurement of how far the blade is from the insert opening on the top.

After the arbor is properly adjusted, then the motor pulley is adjusted to align with the arbor pulley. The motor shaft does not have to extend all of the way through the pulley. I have never worked on a PM 66 that I could not get the 3 belt pulleys to properly align.

Below are some pictures of a couple of saws.

http://i123.photobucket.com/albums/o303/chrisrosenb/100_0487-1.jpg

http://i123.photobucket.com/albums/o303/chrisrosenb/100_0555.jpg

http://i123.photobucket.com/albums/o303/chrisrosenb/100_0556.jpg

[Paul Murphy]

Ok Ken, I’ll also try to help here as I have a pm66 out in my shop.

First, just to clarify something that may or may not be obvious. The side-to-side location of the arbor assembly is determined by tightening the setscrew at the top of the lift arm. That setscrew will bear against a sleeve that separates the 2 arbor bearings. In my saw I don’t remember there being any snap-ring on the lift arm, just the setscrew. (There was a snap-ring on the arbor shaft holding the arbor assembly together.)

Second, all this side to side arbor adjustment serves a purpose. The perfect side measurement for your saw will be different than for my saw. If I remember correctly, the Leecraft ZCI has an initial ~1/4” groove located at the approximate correct blade location. Leecraft had to do this because the full thickness of the ZCI intrudes on the 10” dia cutting zone…if they didn’t provide a clearance groove, you would have to make your own with a smaller blade, and until you did the ZCI wouldn’t sit flush to the table with a 10” blade mounted.

OK, back to the side to side arbor adjustment purpose. Your trunion bolts to the cabinet. The table bolts to the cabinet. The cabinet is sheet metal and welded cold-rolled steel, and each one is a little different than any other…it is not a precision assembly, and may further deform due to resting on an irregular floor. (Same for Delta unisaw, or your Grizzly. Only the cast iron cabinets like on I think the Northfield are any degree of truly rigid.) With the irregularity of stamped steel cabinets, the saw is assembled with shims to “level” the table to the blade when the blade is tilted. There is a sequence to this adjustment, and if I remember correctly it goes like this:
1) Adjust table by twisting to bring miter slots parallel to vertical blade.
2) Tilt blade and shim table to level. This is correct when the distance from the miter slot to the rear of the tilted blade is the same as from the miter slot to the front of the tilted blade.
3) Adjust the arbor side-to-side so that the arbor side of the blade crossed the same point on the ZCI when the blade is tilted as when the blade is vertical.

Whew! Glad we got through that! It’s not rocket science, but it is a little fussy, and takes a couple hours for a slow guy like me to get it right. If the side-to-side isn’t set correctly, then teeth that clear the factory insert when the blade is vertical might hit one side or the other of the factory insert when the blade is tilted. One other reason to get the proper side-to-side adjustment is so your fence scale is accurate with the blade vertical, and remains accurate with the blade tilted.

Ok, you can now see how 2 perfectly adjusted similar saws can have slight differences in the blade to ZCI edge measurement. That said, I’ll post this and then go measure my saw, which is in a building 500’ from my house. I’ll post the measurement in a few minutes.

Oh yeah…do a google search for the manual for your saw. You can download them from Powermatic, some tool dealers, and I think from the OWWM website also. They have instructions, diagrams, and part numbers. Very handy!

[Tony Joyce]

Ken,
I don't know if this helps, but this is my PM66. The arbor was replaced by me and located where the original was. Saw blade tracks in the center of the original PM insert slot. I traded with the guy who bought this new, so it should be correct. The set screw in the top locks the arbor in place. I think there was an internal snap ring on the pulley side, not sure. Three groove pulley on the arbor and the motor. The motor pulley has been removed when it was rebuilt from 2HP single phase to 3HP three phase, but I seem to remember the pulley hanging past the end of the shaft. Hope this helps.

165329 165328

[ken carroll]

Guys,

Phew! Thanks for the prompt and comprehensive replies. As you can see from my pictures I do have a snap ring on the arbor shaft but it isn't bearing up against anything, I really couldn't see the point of it.

It's clear from the pictures you all posted that my arbor sits further out of the arbor housing than any of your saws.

Must admit, I had never thought of that involved alignment procedure of tilted to square when installing a new set of bearings. My table had no shims at all (big surprise - probably thrown away in the past)

How easy should it be to remove the arbor from the bearings with the bearings in situ? A couple of (light) taps on mine show it to be in there very tightly.
The bearings feel really nice so I'd rather not trash them or replace them if I don't have to but I can't just press them in more by the threaded end of the arbor shaft, I need to apply the force to the outer race.

BTW the photos were taken after I removed the set screw.
ken

[Paul Murphy]

OK, back from the shop.

PM66 has a nominal 5-1/2” left slot to blade body measurement. My saw is about 5-19/32”. My ZCI has the kerf about 1” from the left edge.

I have an unused Leecraft ZCI which has ~3/8” relief groove with the left edge ~27/32” from the left edge.

Hope this helps get you in the ballpark.

Once you have it all set you can build your crosscut sleds and various jigs. If you ever move, or have to replace any worn parts you can quickly get a ballpark alignment by placing the blade in the crosscut sled kerf. Take your time, and all your jigs and sled will function correctly

Oh yeah, ask Chris to post a picture of his shop built motor cover. If I remember correctly he built a really nice cover.

[Paul Murphy]

Guys,

Phew! Thanks for the prompt and comprehensive replies. As you can see from my pictures I do have a snap ring on the arbor shaft but it isn't bearing up against anything, I really couldn't see the point of it.

It's clear from the pictures you all posted that my arbor sits further out of the arbor housing than any of your saws.

Must admit, I had never thought of that involved alignment procedure of tilted to square when installing a new set of bearings. My table had no shims at all (big surprise - probably thrown away in the past)

How easy should it be to remove the arbor from the bearings with the bearings in situ? A couple of (light) taps on mine show it to be in there very tightly.
The bearings feel really nice so I'd rather not trash them or replace them if I don't have to but I can't just press them in more by the threaded end of the arbor shaft, I need to apply the force to the outer race.

BTW the photos were taken after I removed the set screw.
ken

Hi Ken, If we are talking about the arbor shaft snap ring, it just holds the bearing/spring washer/sleeve/bearing to the arbor with the correct "play".

Unless your bearings are bad, all you need to do is shift the arbor assembly to it's correct location. The arbor assembly "floats" on the outer bearing races within the lift arm bore. The arbor assembly should move laterally without any type of force that would damage the bearings. Sometimes at shift change 2 setscrews have found their way into the same threaded hole, so check for that. Unless someone has used locktite on the outer races, or burred the bore, the arbor assembly should move with just hand pressure. You can try wd-40 if you think the bore may have rusted aroind the bearing races.

I had to buy the entire arbor assembly, as powermatic doesn't sell the seperate parts anymore. I think it was about $80, but it was an easy r&r, and more accurate than the original.

[Paul Murphy]

3) Adjust the arbor side-to-side so that the arbor NUT side of the blade crossed the same point on the ZCI when the blade is tilted as when the blade is vertical.

Just making sure there is no confusion, that way the scale reads true for both a vertical cut and a cut with the blade tilted.

[ken carroll]

Thanks again everyone - this really is a super useful site with knowledgeable people!

The arbor came out with a few taps from a deadblow hammer. When I reseated the bearings - which as you suggested - was a by hand (no force required) operation, it seated a good 3/16" deeper straight away.
I need to take the measurements given back to the saw and fine tune it as instructed.
BTW, I don't have a "wavy" washer on my arbor. I can't see how it would make much of a difference anyway but I'm willing to be educated!

ken

P.S. Now I feel a chump for turning off the chipped out portion of the arbor pulley as outlined in my earlier pm-66 thread.
Now I have to go buy a new pulley! I assume I can get something from McMaster, or is there a reason I should buy from Powermatic?
They probably only carry the 2 groove 3vx pulleys anyway come to think of it.

[Paul Murphy]

Thanks again everyone - this really is a super useful site with knowledgeable people!

The arbor came out with a few taps from a deadblow hammer. When I reseated the bearings - which as you suggested - was a by hand (no force required) operation, it seated a good 3/16" deeper straight away.
I need to take the measurements given back to the saw and fine tune it as instructed.
BTW, I don't have a "wavy" washer on my arbor. I can't see how it would make much of a difference anyway but I'm willing to be educated!

ken

P.S. Now I feel a chump for turning off the chipped out portion of the arbor pulley as outlined in my earlier pm-66 thread.
Now I have to go buy a new pulley! I assume I can get something from McMaster, or is there a reason I should buy from Powermatic?
They probably only carry the 2 groove 3vx pulleys anyway come to think of it.

Ken, the "wavy" washer is fractionally smaller than the outer bearing race, and is next to the sleeve spacer. Being only about .01" thick, and compressed by the sleeve it is easy to miss. For all I know I'm describing a part that was a change somewhere between your saw and mine! That's why a manual for your era saw would be worth downloading.

I would be content with your 2-belt pulley. I can't imagine any belt slippage without a power feeder ripping max thickness stock. I have the 2 belt version, and in over 10 years of use it has never had any belt slippage that I'm aware of.

Here is a site where the author does a nice job of explaining alignment:
http://woodgears.ca/delta_saw/alignment.html

Relax, enjoy the process, and you'll have a really nice cutting saw. In my experience most machines, even brand new premium equipment, will require some form of adjustment to perform up to it's potential.

[ken carroll]

Paul,

Thanks, I was hoping - somewhat in vain I suspect - that my power issue is one of two 4L230 v belts versus 3 rather than either a RPC problem or a motor problem.
I need to teach my wife how to force a 4x12 plank through the blade so that I can measure the voltages at the motor under load. They look good just spinning the blade, but that's not much of a test.

A 3hp 1ph Grizzly with a Taiwan motor shouldn't be more powerful than a 5hp 3ph Baldor!

It would be a lot of hassle since it's in my garage vs my wood workshop but I could use the RPC that runs my mill/lathe to eliminate the Anderson RPC as the problem.

Then it'd just be the motor......or the magnetic switch....or wiring..... sigh....

Oh, back to the alignment. Tilted at 45deg, the blade is about 3/32" further away than it is at 90deg. I can't visualize whether I need to move the arbor in or out to reduce that error. Hopefully the article you reference will explain.

[Paul Murphy]

Ken, sounds like your wife is willing to help, and that's great, but let's keep her safe. Why not teach her to read the meter while you feed stock.

It might be worth bringing the motor and/or RPC to a motor service for testing. I have done it in my region, and the charge was about $60. Depends on how much troubleshooting you want to do yourself.

Alignment. You don't mention if you are measuring from the left miter slot or the right, so...but no matter. Move the arbor about 1/16" right and remeasure. You're either near zero error:), or at 3/16 error:eek:.
Here is another link to another writeup that might better help visualize the process:
http://books.google.com/books?id=s_YDAAAAMBAJ&pg=PA30&lpg=PA30&dq=aligning+tablesaw&source=bl&ots=B1AdnBvdX_&sig=fU7jtAk1GABDx6w55IQvm78qOY0&hl=en&ei=LrTETPm9JYafnwfw_bGLCg&sa=X&oi=book_result&ct=result&resnum=6&ved=0CCQQ6AEwBTgy#v=onepage&q=aligning%20tablesaw&f=false

[ken carroll]

Hi Paul,

Heh heh, I agree with you re the safety. I actually just got in from my workshop where I rigged it up so that I could feed the stock and view the meter myself.
Interesting
Free spinning vs heavy load on the three legs I get:

W to B 245/220
W to R 229/229
R to B 233/233

So one leg is definitely "different" from the other two in that the lightly loaded voltage is somewhat higher and it takes a bit of a dive - over 20 volts worth under heavy load.

I bypassed the mag starter so it is out of the running as the culprit.

So, it's either the motor or the RPC......still.

Thanks for the reference on alignment, I'll read it.

ken

[Paul Murphy]

OK, short and sweet if you have a perfectly adjusted arbor and shift the arbor right the blade cut line will shift even further right when tilted to 45.

If you have a perfectly adjusted arbor and shift the arbor left, the blade cut line will shift even further left when the blade is tilted from vertical to 45.

I did the math on the geometry of your 3/32" cut line shift, and your arbor needs to be shifted 15/64" to zero that error.

[ken carroll]

Thanks Paul,

It looks like I need to shim the table top too. At 45deg tilt, the blade is now on the vertical line at the back, but still 3/32 off at the front.