Why does my table saw blade wobble?

Any imbalance in a circular saw blade will cause vibration. This imbalance can come from three places, lack of concentricity, uneven brazing of the teeth, or uneven offset of the teeth. Each causes a different type of vibration, all of which increase operator fatigue and increase the severity of tool marks on the cut wood.

Checking the arbor

The first step is to make sure the problem is due to arbor wobble. Get a good finishing blade, and start by cutting just a millimeter off the edge of a piece of lumber. Then, stop the saw, slide the lumber back against the edge of the blade, as shown, and turn the blade by hand to see where in the rotation it rubs against the piece of lumber.

In the position where it rubs the most, mark the arbor shaft with a permanent marker. After doing this, loosen the nut for the blade, turn the blade a quarter turn, and re-tighten. Again, check where it rubs (previous step). Do this a few times. If the place it rubs stays roughly at the same point of rotation of the arbor, then it’s the arbor that’s wobbling, not the blade. If the rubbing moves with the blade, then the wobble is from your blade.If you have a dial indicator, it’s fun to measure the wobble. At about 1″ from the tips of the teeth .002″ variation or less is good. But .005″ variation or more won’t give a clean cut.But just touching the blade to turn it will deflect it. It’s best to take the drive belt off and just spin it by grabbing the arbor for this measurement.

Grinding the wobble out

Clamp a rough (low grit number) grinding stone at a 45 degree angle to the heaviest piece of hardwood you have. Some heavy angle iron or bar steel would be even better, but use what you have.

With the saw running (with the belt back on), lightly push the stone against the flange of the arbor. Ideally, push it so lightly that it only makes contact with the arbor intermittently. As it’s rubbing against the flange of the arbor, move the stone forwards and backwards (away and towards you in the photo), and crank the blade up and down. The stone might get clogged up easily, so you might have to flip it over.

You may also see the occasional spark as you do this. This is ok. Just don’t let the arbor get too hot, as that might affect the accuracy of the operation. You should see sparks coming off it.

The ends of the stone do get full of metal this way, but seeing that this part of the stone is not used for sharpening, it doesn’t really matter. A coarse stone is better than a fine stone because it takes longer to clog. In the mean time, the saw arbor should end up being almost mirror smooth, even with a relatively coarse stone.

Truing the arbor flange

You can check the flatness of the washer by putting it on a flat surface, and pushing it along every spot along the edge. If it rocks up ever so slightly from doing this, then it’s not really flat. It’s a good idea to have a finger straddle the table and flange on the other side, and push firmly on the opposite side. It’s easier to feel small displacements with the finger on the opposite side than it is to see it rock up. A displacement of just .001″ can be felt very distinctively if your finger is in contact with both the flange and the table.

If the flange is not flat, put some fine sandpaper grain up on the table, and just sand the flange flat. Use circular strokes, and push with a finger in the middle of the hole. With pressure applied to the middle of the disk, and the disk rubbing against a flat surface it should get flat. Turn the disk by 90 degrees every once in a while as you do this.

Next, checked to see if the surface where the nut touches the flange was parallel to the wide side of the flange. Sanding the nut side of the flange parallel is an iterative process. Once it’s established where the high spot is, put pressure on that part while sanding.

Saw blade quality problem

Reason: The saw blade is poorly made and the stress distribution is uneven, which causes vibration when rotating at high speed.

Solution: Purchase high-quality saw blades that have been tested for dynamic balance.
Check the saw blade before use to ensure that its stress distribution is even.

The saw blade is old and damaged

Reason: The saw blade has problems such as wear, uneven saw plate, and tooth damage after long-term use, resulting in unstable operation.

Solution: Check and maintain the saw blade regularly, and replace old or damaged saw blades in time.

Make sure the teeth of the saw blade are intact, without missing or broken teeth.

The saw blade is too thin and the wood is too thick

Reason: The saw blade is not thick enough to withstand the cutting force of thick wood, resulting in deflection and vibration.

Solution: Choose a saw blade of appropriate thickness according to the thickness of the wood to be processed.Use thicker and stronger saw blades to handle thick wood.

Improper operation

Reason: Improper operation, such as the saw teeth are too high above the wood, resulting in vibration during cutting.

Solution: Adjust the height of the saw blade so that the teeth are just 2-3 mm above the wood.

Follow standard operation to ensure the correct contact and cutting angle between the saw blade and the wood.

Saw blade vibration not only affects the cutting quality, but also may bring safety hazards. By checking and maintaining the flange, selecting high-quality saw blades, replacing old saw blades in time, selecting appropriate saw blades according to the thickness of the wood, and standardizing operation, the saw blade vibration problem can be effectively reduced and the cutting efficiency and quality can be improved.