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How To Fix Table Saw Blade Wobble And Know Its Cause

What Is Saw Blade Wobble?

Table saw blade wobble is when the blade has lateral movement while at full spinning speed.  Blade wobble can cause cuts to become inaccurate but more importantly they can also become dangerous.

This movement which we call wobble causes the cutting tip of the blade to deflect off course.  This is called blade runout.  Know that every blade will have some degree of natural runout but should be limited to a couple thousandths of an inch.

What Are The Common Causes Of Saw Blade Wobble?

There can be multiple causes of blade wobble.  Most often the fix will be easy.  Dirt and debris can be the likely culprit and cleaning the saw blade is needed.

Not mounting the blade properly to the arbor can also be a common cause for wobble.  Ensure that the blade is seated firmly against the flange and arbor nut being properly secured.

forrest blade

Mounting the saw blade can become tricky at times if multiple washers or spacers are used for things like dado setups.  Each must be seated flat against its mating partners when locked in its place.

Issues can also come from the saw blade itself not being flat.  While most quality manufacturers rarely have issues, some off brand or common hardware store brands can.

The bearings of a table saw can go bad over time.  These bearings can cause the arbor which supports the saw blade to have some play.

If bearings are the issue it is important to replace them as quickly as possible in order to not cause further damage to other parts.  You should at some point in recent history have heard grinding on startup giving indication to this.

It could also be that the arbor hole on the blade could be out of round.  On quality table saw blades this would be a very rare issue, but it can happen.

Temperature Of A Saw Blade Can Cause Wobble

Heat is an enemy.  If you are cutting and your blade becomes excessively hot it can cause issues.

This heat can create distortions within the blade if allowed to continue.  With table saws this generally is not a major problem unless you are asking of it things that are outside of designed specification.

Where you see normal operation of a table saw generate excessive heat comes from the material being cut, the blade being used, and volume of the cut.

You can adjust the rpm of the saw to help compensate for some of this heat issue if needed.  This adjustment I would not make unless this type of cutting is your standard day to day process.

How To Discover Which Issue Causes Blade Wobble

It can become a process of elimination but starting with the easiest solution first is obvious.  Clean the arbor, arbor nut, and ensure that the blade seats flat against the flange.

Just as a heads up, normally you will not have easy access to the bearings.  These should be encased and if sealed properly no cleaning should be required.

freud blade

The next potential for blade wobble is the blade itself.  Many suggest laying the blade on a flat surface to ensure that it is indeed flat.

While not scientific it will at least let you see if something is way out of whack.  There are gauges that you can use to measure more efficiently for this purpose.

It may be necessary for you to also run the gauge against the arbor flange itself.  If the flange is the issue it may be best to replace.

A saw blade typically can deflect up to about .004 of an inch and be okay.  If you push to .005 of an inch then you begin to see some rough cuts.

Achieving a smooth wood cut requires more than a saw blade being in good condition. Nevertheless a rough cut can be an indicator of something amiss.

The arbor flange should not deflect more than .001 of an inch.  If it is more than this then it can be an issue.

You also need to check the arbor nut.  It too must be flat and to the same .001 of an inch specification.  This one is easier to fix or grind down than the arbor flange on your own.

Now to break down the reality of measuring these issues.  The gauges we purchase for under 100 dollars really are not that great at measuring to this degree of accuracy.

What you are looking for is how much the measurement changes from one place to another.  Take this educated guess and you can decide to attempt smoothing out the issue or replacing the part.

What To Do If The Arbor Flange Causes Blade Wobble

The best solution is to replace the flange.

I do know of guys who have ground the arbor flange down with a sanding stone while the machine was running.  How they accomplished this I personally say is outside of scope for a novice and can be dangerous.

A method such as this can cause other issues.

Should You Use DIY Methods Of Repairing Or Install New Parts?

I know a lot of woodworkers love to dive in and diy on fixes.  On many things I do as well.  Yet lets look at some realistic issues.

When it comes to the arbor flange and nut you are talking about trying to get a surface as true to .001 as possible.  Most diy methods risk causing more error than less.

You also may have a gauge which can measure some deflection but is not capable of being calibrated for such fine differences.  Thus if you do decide to diy there is no way to know how well it worked before cutting.

It is far better to replace these parts with new ones.  We cannot machine to the specifications required in our home wood shops.  Let those who have this ability do what they do best.

Does Belt Drive Tension Impact Blade Wobble?

I have heard some associate blade wobble with the belt drive tension.  Improper tension can cause vibration.

Note that this vibration does not cause issues with the arbor, flange, or nut.

Under normal conditions if all things check out as okay and you still are noticing rough cuts you may need to look at the belt drive.

The issue of blade wobble and belt tension while two different things, vibration can “appear” like wobble.

To adjust the belt drive tension refer to your manufacture specifications.  Set according to what is recommended or replace the belt if needed.

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