Replies

1. 
   mapleman | Nov 22, 2007 06:31am | #1

   David,

   I can't comment on the motor bearing issue, but I had a similar problem with a loose pulley on my powermatic 66 tablesaw. The loose pulley wore the shaft end unevenly and also wallowed out the pulley hole (the bearings were bad as well - I suspect the excessive heat fried these as well). I ended up having to replace all of these items.

    If I were you I would check for any wear on the pulley hole (it should fit snug without any play on the shaft). If this looks ok I would use some blue loctite on the grub screw(s) and replace. Check for heat after 5-10 min use for the next few times. If the pulley comes loose again you either have a bad pulley or worn shaft end or both.

   Good luck,

   Lee

1. 
   davidbrum | Nov 22, 2007 10:42am | #2

   Thanks Lee. Glad to hear that somebody else has had the same problem.   I did check the fit of the pulley and it is still pretty snug.  I tightened the heck out of the grub screw but may still go back with loktite. 

   Guess I'll do some research on replacing that motor bearing.  Ugh.

   Davidb

2. 
   philip | Nov 22, 2007 11:21am | #3

   David,
   Re your question two: sounds like a bearing is dry-it is quite simple to replace bearings in that motor provided you are patient, have the interest and some basic mechanical knowledge. I assume it is single phase and it probably has centrifugal starting switch gear-here is where you need to be careful not to damage this mechanism. If it is capacitor start and run then that little complication is avoided.
   If you have a bearing puller use this to pull the bearings off the shaft-both of them-best to replace both even if one has gone.If no puller on hand you should stiil be able to get them off by using a brass drift to tap them off.Be careful not to damage the rotor.
   The fan itself is often just pressed on especially if it is plastic, but some have a key or a roll pin to be drifted out.
   The bearings themselves , one on each end, possibly a bigger one on the drive end, are usually a light press fit in the motor end shields. The fit on the shaft is normally a bit tighter. When you fit the new ones it is preferable to find a piece of tubing/pipe that fits the shaft so that you can tap the bearings into place on the shaft- the tube should bear against the inner ring of the bearing-on no account should the outer ring be pressed or hammered.
   Check to see that the old bearings were not turning in their housings in the end shields- hopefully this was not the cause of the noise you mention. If this has happened and the housings are not damaged then you can use some Loctite Bearing Fit to prevent this happening again
   The bearings themselves will be common deep groove ball bearings no doubt so you can either take them to a bearing shop for matching or just copy the numbers off them to get the replacements. Some motors even have the bearing specs written on the motor name plate. Be sure to get bearings with dust seals not just ordinary shields- wood dust gets into almost everything....
   Bearings and woodwork machines go hand in hand-it pays to know something about them as there is no escaping the fact that bearings suffer from dust and can have a tough life.

   Philip Marcou
1. 
   davidbrum | Nov 22, 2007 07:03pm | #5

   Thank you Philip.  I screwed my courage up and disassembled the motor this morning.  It came apart quite easily and I located the bad bearing right away.  I do have a bearing puller.  I think this will be a lot less work than imagined.  The OEM bearing is a 6903Z which I think is pretty common.

   BTW should I replace both bearings while I'm in there or should I let sleeping dogs lie?

   Thanks so much for your encouragement!

   Davidb

1. 
   philip | Nov 22, 2007 09:51pm | #8

   I would replace both. If one still feels sweeet you can always keep it for stand by use or some other application.
   I see that the number is 6903z- the z tells one that this is a SHIELDED bearing with one shield-6903zz would mean two shields. If it said 6903 2rs this denotes two DUST SEALS. Does your motor have grease nipples? If so be sure to have the seal or shield facing the right direction...
   But for this application I think it is preferable to install bearings with two DUST SEALS, rather than use the shielded type, and then there is no need to grease them. Sealed bearings are pre-packed with grease and require no further greasing for their life.
   Anyway, they are easy to dis -assemble, and the inner and outer rings make good spacers for various applications, since they are accurately ground.If you have pairs of these they are useful.
   Let us know when you hear the hum of a sweet-running motor...Philip Marcou

   Edited 11/22/2007 2:15 pm by philip

1. 
   davidbrum | Nov 23, 2007 08:03am | #9

   Yes!  I found one of the correct bearings at my work this morning.  Turns out to be the same bearing used for the crank on some kid's bicycles.  It was even double sealed.  It went right back on and now the planer sounds much happier.  The other bearing seems fine, but I did record it's number for future reference. 

   I made a new grub screw which I installed with blue loctite.  Hope it holds.  I still need to get some decent belts pretty soon.  Will probably order 6 or 7 feet of link belt since I found a cheap source recently. 

   Thanks again for the encouragement.

   Regards,

   Davidb

1. 
   KiddervilleAcres | Nov 23, 2007 08:57pm | #10

   Nay, nay David. 

   You can't post that without telling us the cheap source of the link belt!  The wood gods will have a field day with you.  I'm simply looking out for your best interests.

   Glad to hear your bearing issue is resolved.

   Regards,Bob @ Kidderville Acres

    

   A Woodworkers mind should be the sharpest tool in the shop!

2. 
   davidbrum | Nov 23, 2007 09:30pm | #11

   I appreciate your concern Bob.  Here's the site:

   http://www.cshincorporated.com/index.php/cPath/119

   Belt prices are around 30% cheaper than the standard WW sites. 

   Davidb

3. 
   philip | Nov 22, 2007 11:35am | #4

   David,
   just a comment on pulleys "secured" to shafts/arbors by grub screws: this is an inferior method and prone to failure especially if the screw can work loose and ESPECIALLY if the screw does not go into a recess or counter sink on the shaft.
   If yours are merely relying on the dimpled or serrated end of a grub screw or two then you can improve the situation by lightly counter drilling for them. The position will be marked on the shaft by the grub screw....
   Pulleys should be keyed onto shafts with either a wood ruff key or preferably a straight rectangular peice of key steel, but manufacturers seem to assume that they can omit this sort of detail because a) the machines are aimed at the hobbyist and b) seems like a good way to cut costs.....

   Philip Marcou
1. 
   davidbrum | Nov 22, 2007 07:09pm | #6

   Philip, this pulley has a rectangular key which fits into corresponding grooves in the arbor and the pulley.  The grub screw bears against the key.  Do you think that drilling a recess into the key would help?  If not, would this be a good application for one of the Loktite compounds?

   Thanks!

   Davidb

1. 
   philip | Nov 22, 2007 09:44pm | #7

   David, drilling would be best, but use of one of the lower strength Loctite retainers would also be fine.If you have some new grub screws this would be good as well.Philip Marcou