Tablesaw Blade “flutter” Question
Hi – I’ve got a 10″ Delta Contractor’s saw, and, until recently, it’s performed satisfactorally for my level. But, recently, the saw started acting real funny: When ripping or crosscutting, unless the stock is passed thru very (and I mean VERY) slowly, the blade will flutter or vibrate for a while, then settle down again.
The result of this is that my ripped and crosscut edges aren’t smooth, with up to 1/16″ across some of these blade-curf scars. I’ve been accounting for this by cutting slightly bigger than desired, then doing a final trim with only a portion of the blade on the stock. The blade is a a new $50 Freud blade, and it worked great 2 months ago when brand-new, so I suspect the problem may be in the machine itself. I have milled a fair bit of cherry, but I shouldn’t think the blade would be dull yet. I haven’t taken anything apart to investigate yet, and would appreciate any advice. I did look at the motor while the saw was running, and noticed that the belt vibrates a little bit, which makes the motor vibrate up and down on it’s pivot (about 1/4″ up and down). Don’t know if this is normal or not. But, I would think that the problem may be within the blade/arbor/trunion itself? (I don’t really know what arbor and trunion mean, but I know they’re part of the saw, right?) Another characteristic of my shop that may affect the saw is that the floor is not perfectly flat, and I have to sometimes shift the saw around until it’s relatively stable on the floor. Any suggestions would be appreciated.
Erik, Edmonds, Washington
Replies
Erik, that sounds like a lot more flutter than one would expect even from a bad blade. If you grab both sides of the blade can you cause any movement to occur? Also, if you motor is hopping around that much, I would suspect that you either have a burn on the belt or the belt has taken a permanent set.
I would start by looking for the obvious. Verify that the blade is flat and true then check the belt followed by the drive system geometry. If all of that checks O.K. and you don't have any slop in the arbor bearings then that might indicate a problem with the arbor itself.
Steve - in Northern California
Steve - thanks, I'll check and let you know the outcome. Erik
Agreement here with Steve, and I'll add the obvious (cause I've been there). Remove your blade again, and check the blade and collar washers for any pieces of wood or such.
Gerry
The advice you have been given is right on. I am thinking that if the blade settles down after a while, the belt has taken a set. This means when you shut off the machine the belt is hot and when you start it up it is cold and the sharp turn arount the pulleys tends to want to stay that way. A link belt is the best solution for that particular problem. I have seen in large cabinet shops that they start the tablesaws in the morning and leave them running all day. Sounds dangerous to me.
The other thing is that if your new blade is thin kerf you should have a set of blade stableizers on it. I had to do that to my contractors saw to keep the flutter and flex down. The flex came in when I was trimming close to the edge of a piece of wood the blade would flex towards the short end. By close I mean 1/16 - 1/4".
Good Luck
John
Erik
It sounds more like bad bearings to me. Same thing on my Unisaw when the bearing started to go. Noise during cutting and some flutter was noted.
Curt
Sounds to me like the blade has lost its tension. Try a different blade before you start tearing into the belts, arbors, etc.
My guess is that at some time before this fluttering happened, you overheated your blade. What you are describing sounds to me like blade harmonics and critical speeds. A critical speed is one (actually there are likely several) where the rim of the blade will develop an oscillation. If you look closely, all circular saw blades will vibrate at certain speeds during start-up and shut-down.
Take the blade to a QUALIFIED saw service, Get it resharpened (because its there) and get them to roll tension it. Some shops will not charge you for this extra work because it is part of normal saw doctoring.
I agree, try a good properly tensioned blade like Ridge Carbide and see what happens.
Erik,
Just one more thought to add to the good ideas already posted: had you recently removed the blade and reinstalled it just before you noticed this fluttering? sometimes you can make a slightly off-tension blade and a slightly warped arbor cancel each other out by rotating the blade to a different position. Make a mark on the arbor and on an adjacent point on the blade near the arbor and make a test cut. Then loosen the arbor nut and rotate the blade about 90 degrees and make another cut, etc., and see if the fluttering gets better or worse. GP
Hi Erik! Another WA Stater here (Bainbridge Island). Seeing your thread, and all of the ideas and suggestions, brought to mind a post from a few weeks ago. Can't remember who it was, but they had just moved their Powermatic (?) saw, and suddenly it just wouldn't cut right. The poor guy checked everything and even went so far as to pay a service tech to come out and look at the saw. In the end, it turned out to be a bad blade.
'twere it me, I'd check the basic stuff like belts and blades (as mentioned above) before tearing into major parts. Good luck!
forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Edited 5/14/2002 1:59:38 AM ET by forest_girl
Pull the blade off and check it carefully. It may be cracked or warped. Lay it on the table to check for warping. Are any carbide teeth missing?
PlaneWood by Mike_in_Katy
PlaneWood
Erik, I had a Delta contractor's saw for over 20 years and never had a lick of trouble with it. I edge-glued hardwood straight from the saw. My motor was a bit bouncy too. I replaced the original pulleys with machined steel pulleys and put on a new belt with less of a bump in it and that helped the vibration some. I think the new link belts are probably better but I've never tried one. Could you have knocked your table out of adjustment? I'd check that the blade is parallel to the mitre slots. If it's off a little bit, you'll get blade noise, burning (especially on cherry) and a bit of flutter.
Hi: steve, gerry, john, curt, niemiec, qp, forest_grl, mike, planewood-mike, terry, and dave; thanks for all your thoughtful input. I found the major contributor to the problem: the locknuts on the blade tilting and blade raising handwheels weren't tight. The locknut on the raising/lowering handwheel was really loose. This slop allowed the whole blade/arbor assembly to move up and down slightly. I didnt' realize until I read my manual that these were supposed to remain tight. I believe that this Freud blade, a full-curf blade, probably the heaviest (definitely the most expensive) blade I've run, tends to vibrate more under load than other blades. This natural tendency of the blade to vibrate under load, coupled with the slop due to the un-tightened lock-nuts, caused this flutter. The flutter may have been even more dramatic up-and-down than side-to-side, but the sts flutter is what is noticable.
Now that the locknuts are tight, I still have some very slight saw kerf marks along ripped edges, but not nearly as bad as before. Thanks!
Erik
Eric -
A lot of people will not bother to loosen the lock nuts when adjusting the height or angle of the blade. Take it from me that the locking mechanism will quit functioning eventually if you don't. They should be loosened and retightened every time you adjust the blade. Pretty obvious really, but you'd be amazed how many people don't bother with loosening them first.
PlaneWood by Mike_in_KatyPlaneWood
This forum post is now archived. Commenting has been disabled