A Fix For The Lightweight Machine Tool Shakes

No matter what material you work with, the general rule is that with machine tools, the heavier, the better. Some people can’t afford or don’t want big tools, though, even with their natural tendency to reduce vibrations. That doesn’t mean something can’t be done to help the little tools, like reducing vibration in a contractor-grade table saw.

This one might seem a little outside the usual confines of the hackosphere, but nobody can doubt [Matthias Wandel]’s hacker chops and he really shows off his problem-solving skills with this one. His well-worn contractor-style table saw has had more than a few special modifications over the years, some of which left it with a shimmy sufficient to vibrate workpieces right off the table. He fashioned a friction damper for the saw’s motor from wood, complete with ball and socket joints to allow full movement of the blade height and angle. That didn’t quite do the trick, but his incremental approach finally found the right combination of factors, and the video below shows a saw now stable enough to balance a nickel.

If the name seems familiar but you just can’t place the hacks, check out [Matthias]’s recent wooden domino extruder, his shortcuts to tapping wood, or of course his classic wood gears layout software.

12 thoughts on “A Fix For The Lightweight Machine Tool Shakes

  1. This is the joy of hacking – fixing something the way you like rather than what might be optimal. You’re going to get dozens of suggestions so mine is to mount the motor solidly, use a longer belt and a tensioner to keep the blade powered at all levels (or rebuild the mount properly so that it’s actually stable as it moves – I did one for my dad’s 4′ lathe using heavy door hinges and it’s very stable). I’m also a little surprised he didn’t try a wooden pneumatic dashpot – if you can make a fire piston, it should be easy.

  2. I use link belts on two of my tablesaws and on my larger bandsaw. They make a considerable difference. Also, if they get damaged (like a chewed up section), you can remove those links and replace them with some of the ones from the original full-length belt (though that introduces an unworn segment to the used belt), and of course you’re buying a link belt that can be sized to what your tool needs – one spare link belt can be at the ready to replace belts on multiple tools with varying sized belts.

    The pulley and blade arbors can be a significant source of vibration – removing the pulley from your motor and installing a new one can change things dramatically. Planar alignment of the pulleys is also important. It would have been insightful to see the measurements of the pulley v-groove while rotating the motor without a belt. Check both the motor pulley and the arbor pulley for debris.

    Neglected blades (say, not cleaning or sharpening them) will accumulate resins which can off-balance the blade itself, and the resins (or dull teeth) add to friction which can cause the blades to warp, which will induce a lot of unwanted vibrations (and irregular cuts).

    I was unimpressed to find that at the end of the video, the claims of improvement were made while the blade was in a mostly lowered position, rather than fully raised. At the beginning of the video, it was demonstrated that the vibrations were less significant when the blade was lower, and substantially pronounced when the blade was raised.

    1. Yes, this makes the most sense. There shouldn’t be that much vibration, so find its source and fix it. Can you imagine a drill press with that much vibration? Also, his fixes had nothing in common with the one method that really worked: damping it with his hand.

      Oh the other hand, this is Matthias. If there is a way to do it with wood, he will find it!

    2. +1 for linked belts.

      I purchased on old (’80s) Craftsman table saw from Craiglist to refurbish. After a number of modifications, a round of tedious cleaning, and careful alignment of everything there was a significant vibration in the machine. Per a recommendation, I replaced the V-belt with a link belt from Harbor Freight. ALL the vibration went away immediately. The V-belt never returned to a circular shape. Its shape stayed a short and wide oval as if it were still stretched between the motor and the arbor. I should have known not to put it back on in the first place.

      My woodworker friend then informed me of the nickel test. You place a nickel on the table saw while it’s running. If it remains standing, you’re likely good to go. My saw now passes the test. In fact, the saw can pass a penny test as well. I was able to carefully cycle the blade height during both tests without problem.

  3. A proper fix would be either replacing the pulley with a precision one, or using a metal lathe to cut it true. Next, use an automotive type belt. Machinery belts are still made ‘old school’ with a cover that makes them stiffer and often have a lump at the cover joint.

    Then there’s the motor itself. It looks to be pretty old, yet not old enough to be of an age where most electric motors of that size were built to higher standards. The bearings may be on their last legs. The armature balancing may be poorly done. I have two bench grinders. One has a Montgomery Ward motor from the 1940’s or 1950’s. It runs smooth and quiet, takes several minutes to stop. The other is a Chinese import from the late 70’s or early 80’s. It’s *always* been loud and stops very quickly. The only repair it’s ever needed was replacing a broken part in the centrifugal switch. Maybe someday I’ll spend a few bucks on better quality bearings for it.

    A couple of years ago I put an almost new Dayton motor onto a 1943 LeBlond 17×72″ metal lathe. It was horribly loud and vibratey. Turned out the reason it was quickly removed from service then sat around for years before being auctioned was the factory installed bearings were total crap. After removal, I could shake them and feel the inner races and balls rattling around. A pair of new, higher quality bearings had it running very smooth.

    Bearings, pulleys, belts. If a spinny power tool is vibrating, those are the most likely culprits. Masking vibration with dampers doesn’t eliminate the vibration. His saw is still shaking, pounding on the bearings. It’s just damped from reaching the table top.

    1. Yes if he got a 50 grand new table saw every week that comply to NASA standards he would have less vibration, but what is better for normal people is to find a way to deal with the vibration of the system at hand.
      And seeing the final results it shows that the saw as it is CAN be made stable, even with off-the-cuff experimental solutions.

  4. He dampened the table vibrations, not the motor vibrations. His table might not rattle but the blade will likely still cause the part to vibrate once he starts cutting anything because it bypasses all the stuff he just did! As others have said, he needs to inspect the blade, bearing systems, and belts. These make the most differences. That saw looks old, so I bet the bearings are about wore the hell out. He put a new belt on and that helped with the belt deflection…that tells me it’s a wear problem in the drive system.

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