Replies

1. 
   JohnWW | May 03, 2006 01:51am | #1

   I have a Ridgid band saw in my home shop, I'll have to take a look at it before I can give you any advice.

   To be honest though, unless your saw has got a lot of mileage on it, it is highly unlikely that the bottom bearings are failing, and your description of the sound isn't typical of a bad bearing.  If you have one of the older machines, painted gray and made in Taiwan, they had better than average quality bearings for an import, which is another reason why I would doubt that you have failing bearings. 

   If you haven't done this already, check the bearings with both the drive belt and the blade off the machine.  If you are getting a distinct rumbling noise or a bit of grittiness or an occasional catching then the bearings are probably bad.  If in doubt you are better off leaving them alone.  If they are just beginning to fail they will get worse only gradually and until they get extremely bad they won't cause any serious problems or cause damage to any other part of the machine.

   John White 

1. 
   royh | May 03, 2006 03:09am | #2

   Thanks, John.  I'll spin the wheel with the link belt and blade removed and see what's going on. The saw is a recent one with the orange paint(BS14002). I'll get back to you.

   Roy

2. 
   royh | May 03, 2006 02:29pm | #3

   John,

   With the link belt and blade removed, I gave the wheel a spin by hand - - - no rumbling, very smooth. The motor pulley was out of alignment (outward) by 1/16", so I readjusted that. Now, the drive pulleys are co-planar. Re-installed the link belt. Spun again. A little rumble. Added a link to the belt. No rumble. Plugged it in, no blade installed, turned it on; no rumble. Belt too tight? Anyway, that seems ok now.

   Before this, I've noticed that when running the machine, the blade moved forward and backward a little with a little side to side action. With the thrust bearings moved very close to the back of the blade, and the saw running (no load), the blade cyclicly engages the bearing.  On further inspection, the lower wheel seems to wobble a bit. I thought this also was a result of the "bad bearing". Bad axle? Poor seating of bearings? Bent wheel?

   I appreciate your insights and troubleshooting help.

    

   Thanks,  -- Roy

1. 
   JohnWW | May 03, 2006 06:32pm | #4

   Glad to hear that the bearings were good, you've saved yourself a few hours work. 

   Drive belts, whether conventional or linked, act like guitar strings, they have a natural frequency of vibration.  If their natural frequency happens to coincide with the rotation speed of the motor, or a slight imbalance somewhere else in the saw, you can get a strong, low frequency, vibration that will carry through the whole machine.  When this happens, just making a slight change in belt tension, like tuning a guitar string, will change the belt's frequency and get it out of synch with the motor speed or the imbalance, and the vibration will greatly diminish.

   Link belts, because they are segmented, will be a bit noisier, especially when they are tight in the pulleys, so loosening the tension will often make them quieter.  As long as the belt doesn't slip at the lower tension you are better off running it looser.  

   Usually the forward to back motion is caused by a flaw in the blade, typically a misalignment at the weld, although problems with a wheel can also cause the effect.

   To figure out the cause of the movement, rotate the wheels by hand, with the blade installed, and mark the blade with a felt tip pen at the spot where the blade has shifted furthest back.   Rotate the wheels through several revolutions, if the same spot, or spots, on the blade continue to be the point of greatest shift, the problem is with the blade.  If the marked point is different each time you run the test, then the problem is in the wheels.

   Wheels will often times appear to have a wobble because the outside of the rims are usually slightly rough unmachined castings on the Asian made saws.  The point to look at for detecting a bent wheel is the edge of the machined groove that holds the tire.  That edge should have little or no back and forth motion.

   John White 

   Edited 5/3/2006 11:39 am ET by JohnWW

1. 
   royh | May 04, 2006 01:59am | #5

   John,

   Thanks for the details on the belt situation. I barely remember the harmonics lessons from physics classes. I'm relieved I don't have to locate some new bearings; the installation time would be a learning experience for me, however.

   Re: the blade movement - - - the blade is a brand new T-wolf 1/2", 4tpi, 105" from PS Wood. Under tension with guide blocks pulled away, the blade contacts the thrust bearing under the table consistently at a point just before the weld. I didn't check if it happens with the upper bearing, but will do so later this evening. I'll have a look at the inside groove of the wheel as you suggest when I get a chance.  I'll certainly let you know. Thanks again for the input!

   Roy

2. 
   royh | May 05, 2006 01:27am | #6

   John,

   With both bearings adjusted, they both get touched and moved just before the weld passes them . I will pull them away a little and see how the cut goes. Still need to check the wheel groove.

   Thanks, --Roy

3. 
   royh | May 18, 2006 02:38pm | #7

   Dear John,

   The lower wheel inside grooves seem to be ok. I installed a replacement, new T-wolf blade and the forward/backward motion of the blade seems to have disappeared. Also, the default, 105" blade that came with the riser kit rides well also. A resaw on a glued-up panel of 6" walnut, cherry and maple produced thin, even panels of 1/16" or less. I was impressed. I replaced the thrust bearings with some from Iturra as the orginals seemed to whine like crazy. Next, I'll tackle some green apple with an appropriate blade.

   Thanks again for your help and input.

   Roy

1. 
   JohnWW | May 18, 2006 05:15pm | #8

   Roy,

   Glad to hear that things worked out well without a major repair being needed.  I was almost positive that the blade was the source of your problems.

   To cut green wood you have to use a special blade, ordinary blades go nowhere.  Suffolk Machinery, which distributes the Timberwolf line, has a blade for sawing green wood, I highly recommend it.

   John

2. 
   royh | May 19, 2006 01:15am | #9

   John,

   Again, many thanks for the input. This Experts section of FWW.com is a real treasure chest of info.

   Yes, I see that Suffolk has some "green wood" blades. I'll contact them and see what they recommend. Now with a riser installed, I expect I might make more of the resaw. I'm in no hurry, the 3/4 hp motor seems plenty enough for less than 24/7 use.

   Much appreciated,

   Roy

3. 
   royh | May 28, 2006 04:01pm | #10

   John,

   A 2 tpi, 3/4" PC blade from Suffolk worked just fine. The apple wasn't just green, it was really wet! The tree was just taken down 2 weeks ago. Thanks again for the recommendation.

   Roy