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After reading the table saw blade review, I thought a new Forrest blade would be well worth the cost if it saves me significant time in sanding. I say if because I wonder whether it would make a difference given the amount of vibration in my saw. I have a PM 64 contractor’s saw, and despite my best efforts to keep all the bolts tightened and have all four feet standing firmly on the floor, there’s still enough vibration that a board laid on the saw while it’s running will jiggle noticably.
Is this normal for a contractor’s type saw? My proposed remedy — other than throwing down for a heavier cabinet saw — is to try to upgrade my saw to a cabinet style. I think I could modify the motor mount so that the motor hangs directly below the blade instead of off the back of the saw as it does now. I figure this would keep the center of gravity under the blade and provide more stability. I would have to remove the saw’s existing sheet metal housing and stand to accomodate this change, so I would build a full cabinet using 3/4 plywood which I think would be more rigid. I could even pile bricks in the bottom maybe for added heft.
My question is whether these alterations would have the desired effect or whether there are other factors contributing to the vibration that I haven’t considered. Or am I simply asking too much of this level of saw? I assume lots of woodworkers have dealt with this issue, though I’ve heard little discussion of it. Thanks for any help.
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Please differentiate -- is it the sawblade that is vibrating or is it the entire machine center??
The quality of a sawblade (and therein the price value/ratio) depends entirely on how well the blade is sharpened. If you spend money on sawblades and consider them to be a disposable item (that is, you don't resharpen them) then buying the most expensive blade may be worth it. But, if the blade is resharpened, the blade will only perform as well as the sawfiler does his job. After the initial sharpness is gone, it generally doesn't matter who made the blade but instead who sharpens it.
*Some one recently posted curing a TS vibration by replacing the original belt with a link belt. He was very pleased with the change. Try the search.BJ
*Cheap pulleys can give you greif too and I would check out the conditon of the bearings on the spindle as well as look for play in the trunion.
*Vibration can start right at the place where the blade is grasped. If the blade is grasped by two inexpenssive pressed cup washers, I would try heavier (not necessarily larger diameter) machined disks.
*Ditto on the v-link belt. I put one on my Jet contractors saw, made an immediate dramatic difference in vibration level. The rubber belts take a "set" that causes a lot of vibration. I've seen the v-belt offered as a set with upgrade matched balanced pulleys, I think it was in Woodcraft or Woodworker's Supply catalog. Might be worth a try.
*An ounce of prevention ...Cure the vibration at it's source which is the rotating parts. Start at the blade and check runout, also at the arbor flanges. I've never read anything but praise for the link belt and machined pulley option.
*I too upgraded my Jet contractor's saw with a link belt. It was like I had a new saw. My saw was fine when it was new (and progressively grew worse), but was better than new with the new belt. It even seemed to have more power.Brian
*Brian:Are you running your saw on 120v or 220volt? I love the saw, but it's a little underpowered in thick (over 3/4") rip cuts. I get a lot of motor stoppages, tripping the overload circuit breaker on the motor. I've been considering upgrading to 220v, or replacing the motor with a 2hp Baldor. Are you having similar problems?
*One more vote for the link-belt, (I got mine through Lee Valley). The decrease in noise is also quite a noticeable improvement. On the subject of 220v vs. 110v. My experience has been a substantial increase in power. My first table saw was a Delta 9" with a 3/4 hp motor. It had a hard time, but could, cut 3/4" oak with sharp carbide blades. I could not practically cut 8/4 except at the lowest feed rates. The power supply was good as the shop was my attached garage with a plug not three feet from the panel. I switched to 220V and it was like having an extra 1/2 hp. Glided unendingly thru' 3/4 hardwood and cut 8/4 with enough authority to end most all trips of the breakers.Alan
*More confirmation of the "link belt" as the way to go - will effect, by itself, at least a 50% reduction in vibration. Sound/noise reduction: tested with an acoustic sound-level meter at ear level (24" above the blade) - no change. Below the table in back of the saw (near the belt) - a token reduction in noise (1-2 db).Blades out of balance, be it Forrest or whatever brand: possible, but not probable, with little correlation to price. Placing another blade (or two) on a given saw should answer the question of "is it the blade."A reasonably simple method of "seeing" vibration levels is by applying an old car-tire balancing technique: place a glass partially filled with water on the tablesaw surface and note the size of the circular "waves" on the water's surface (while the saw is running), less is best. This method also provides an approximate method of comparing say, saw blades or belts (but not perfect because one has to "remember" what the water-rings looked like during another test.)Last point on vibration: The geometry of four legs supporting any object (a tablesaw in this case) is a major source of problems... and the very reason why photographers used - tripods (3 legs)... three legs "self-level" upon any surface; four legs never will, a nightmare to adjust.Though all four legs of a tablesaw may appear in contact with the floor... they may not press down equally (assuming the floor is - solid - not flexing). Once a little bit of shake starts it well may increase during saw use. Here's a perfect application of watching water-glass vibration rings while applying paper-thin adjustments (shims) under various legs.
*See if the pulleys are in plane with one another by placing a ruler across them. If they are'nt they are fighting one another. You can try adding mass to the saw in the form of a sandbag or two on the legs. Also try bolting it to the floor. That should make the whole assembly much more rigid.Good luck!Tom
*Alex,I run at 110V at the moment. I plan to run at 220V as soon as I get a 'round tuit to finish the job with. I have 10gauge wire running from the circuit box to the outlet and it is dedicated to the saw or my planer (they never run at the same time). I really just have to get out to do it instead of woodworking one of these nights.Brian
*Step 1, Rewire for 220v. (makes a big differance due to less volt drop effect at start up). Step 2, check old belt for cracks of bits missing. Step 3, Install the old blade and check for vibrations. maybe do step 3 first.
*Wow! First, a new cabinet made from 3/4 inch ply will only be of value if you build it using double wall construction. Leave a gap of about 1.5 to 2 inches between the walls and fill this volume with sand or concrete. Thats right. CONCRETE! The stuff in 80 pound bags called sackcrete should work just fine. Make sure that you poke and prod the suff into place as you pour it in to prevent any air gaps. Use nice birch ply or oak ply on the outside to spiff it up a bit. Finish it first before you pour the concrete or mask it off to keep the concrete from messing up the nice sides. This will cut down your vibration problem like nothin you ever thought possible. Martin table saws are made using double wall steel with concrete infill so your not the first to do this.Now, on to power. Go to your bearing/motor store and get a good 3 to 5 horse motor and starter. You will be amazed at what a little more juice will do for the quality of the cut. With the new cabinet, mounting the motor should actually be fun.Use the red link belt drive belts. I have never used these myself but I have heard only good about them.That should do it. Another option would be to sell the saw and get a cabinet saw. My 4th hand martin T-17 may need new paint, but it works nicer than any new offerings.Personally, I would look for a northfield #4 standard without a slider. You can fab up some aluminium plate to fit in the throat plate that will accept a porter cable 7518 router. Now, by changing out your throat plates, you have both a killer table saw and and very stout shaper table in one unit. Talk about space savings. Hook up an optional power feeder and you get both power feed on saw work and on shaper work. Great for moldings, etc.Best of luck.
*I'm probably the one referenced about the recent testimonial to the red v link belt. My new Delta contractor vibrated so badly you could see the motor jumping up and down. With the new belt, it runs smooth as glass and my setup is anything but solid, the saw sits on a dirt floor on two 2x10 pressure treated pieces of wood and shimmied to prevent rocking. Nontheless, the key is to get the weight equally distributed amongst the legs. After the belt, you could try finely machined pulleys which are made to more exact tolerances than the oem. I didn't have to do the pulleys. But these two items are under $50 which is far less than taking the loss on that saw and buying a cabinet (not that you are comparing apples and oranges anyway, there must be a reason you didn't buy a cabinet saw to begin with).Jon
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