table saw blade "wobble"

I have a table saw that I picked up used. Unfortunately, there is blade wobble sufficient to cause scorching on harder woods. There is deviation of about 1/16" at the edge of the blade. I'm pretty sure that the problem is a result of the arbor flange not being symmetrically machined. I've laid a blade on a flat surface, and it seems perfectly flat. I've also swapped out the blade, and the wobble persists. I found the following suggested solution to the problem:

http://woodgears.ca/saw_arbor/

and have not had much luck. I have a sharpening block that seems to get worn away without solving the problem. I can get a replacement arbor very cheaply, but don't have the equipment to press-fit it to the motor spindle.

So, it seems that I have two solutions:

Using some sort of file on the flange (diamond?) and see if I can remove enough material to stop the wobble OR ordering a replacement arbor and trying to find someone who can remove the old one and install the new one. Any ideas? Thanks.

Music321: Remove the blade and "stone" the face that mates with the blade. This is, with blade off, use a fine grade India stone, by

running the motor and apply the stone to the aforementioned face of the arbor for a few moments. this will reveal and probably

remove any high spots or "hickeys". Then unplug the saw and install the blade and if you have a dial indicator, use it to measure

the amount and location of the high spot. At this tine mark the high spot on the edge of the blade and also a mark on the spindle

in alignment with the high spot on the outer edge. Then, loosen the blade and turn its location about 90 degrees in relation with

the two marks. Then, tighten the blade. Then use your indicator to determine if the new high spot is with the original high spot on

the blade or in line with the mark on the shaft. This will help determine the culprit. If the new high spot is with the mark on the

shaft, then that is the culprit, which can be recut on a lathe, rather easily. Yeah, I know, this sounds rather long winded, but it is

rather simple. I hope this helps. Stay safe, my friend.

JH

run out will not "scorch the harder woods" Sap build up and dull blades will.

1/16" is a hell of a wobble for a table saw. If that was a direct drive saw, it could leave an unpleasant experience when ripping stock against a fence!

I take it that this is a belt drive saw? How big is the motor? Please be safe and don't use the saw until you fix this issue.

I have an old Yates-American 5HP direct drive table saw, if it had a blade with a 1/16" wobble I'd be afraid to use it.

I would take it to a motor shop and have them check the arbor if it's a direct drive, or the spindle the blade is attached to if it's belt drive. Sounds like something is severely bent to make it wobble that much.

Cheers,
Alan

I would have to look at replacing the bearings first before I did anything serious. They are most likely the culprit, and easiest to deal with.

First question: what brand of saw and how old? With used stuff its always Caveat Emptor.

Possible causes:
Bent arbor (from traumatic event while cutting). If made in China, may be poor QC.
Warped blade - very common if blade was overheated
burr on arbor flange (perhaps wrench dropped on it while changing blade)
Dirt and debris on arbor flange
Bad bearings

To check, raise blade to max height (with saw UNPLUGGED). Gently push, pull, etc. to check for play (usually bad bearings but there may be a tensioning nut at other end of arbor). Also look for play in trunnions and sector. Often these can be adjusted.

Mark edge of flange with paint dot. Mark blade also and align marks. Check runout, mark blade at point of max runout. Then loosen arbor nut and rotate blade at least 90° before retightening. If point of max runout has moved relative to arbor flange the blade is warped. If not it is likely a problem with the arbor.

In future, try all possible checks before trying a "fix".

music321
We had a local woodworker stop by our shop to have his saw blades sharpened. He wanted to video the process. In the video, you will see some of the steps we take to inspect the saw blades before we re-sharpen the blade. you will see how we check the blade for run out and flatness on the saw plate.

My tablesaw blade gets a grind. - YouTube

Bill

If it's not the blade...

1/16" "wobble" at the periphery means 0.006" to 0.008" TIR at the arbor flange. That's a lot to stone out Woodgear style. You need a hard stone not a frangible stone used for sharpening. Perhaps a file clamped to a wood block. In any case once you've squared the arbor flange, the 5/8" arbor diameter needs to be checked as well. If it's bent, it needs to be corrected or your work will sort of gallop along being cut by only the high teeth. This slows progress and makes saw height settings difficult..

If the arbor is bent consider what it took to bend it. A big shock. Chances are the arbor bearings are affected. When you spin the arbor with your fingers does its movement feel "bumpy"? When running under power without the blade are the bearings noisy - do they whir or howl?

The damage may extend to other parts of the mechanism.Does the arbor quadrant crank up and dow easily? Does it bind at any place. The arbor elevating quadrant is attached to a cradle casting is carried by sector shaped guides for tilting. These should be snug fitting while allowing free movement as the cradle tilts. All this needs to be examined for damage/distortion/excess clearance. You may be well advised to dismantle the saw and examine it for fit, wear, and damage.

Table saws are mechanically simple. How are your mechanic's skills? Got the basic tools for the job? Screwdrivers, wrenches, a plastic or soft metal mallet? Find the saw's manual on line or paper?

You need to examine the saw arbor and the rest of the saw's working parts. There is more than a good chance the arbor is bent. If a replacement saw arbor can be found have it on hand before you set to work. Perhaps the existing arbor can be straightened

Remove and replace the arbor and clean and examine the other working parts, following the manuals exploded part diagram for order and sequence of assembly. If you doubt your ability, prevail on a friend - bribe him with beer - to assist you. Good way to spend a Saturday afternoon.

Have a back-up plan if the replacement arbor is a dud or unavailable. A machine shop will make you a new arbor for about half the price of a whole new saw. Got a buddy with a lathe? Have hem make you a new arbor of heat treated material. Other damage or deficiencies will have to be addressed as you discover them.

Think of it as an education. Beats the hell out of a ball game or a round of golf for tuning up your intellect and developing new skills..

triplechip said:

music321
We had a local woodworker stop by our shop to have his saw blades sharpened. He wanted to video the process. In the video, you will see some of the steps we take to inspect the saw blades before we re-sharpen the blade. you will see how we check the blade for run out and flatness on the saw plate.

My tablesaw blade gets a grind. - YouTube

Bill

Click to expand...

That's the kind of Youtube video I love seeing. I learned a lot, thank you.

Amazing how fast ultrasonic cleaned that blade!

Is the red coating on that blade for anything other than to help it sell? Like...wooo its red, must be better?

The only part of the process I didn't understand was when the blade body was ground on one side.



Thats an awesome shop you have there. I had no idea they made CNC blade sharpening machines that sophisticated.

Qt john: [The only part of the process I didn't understand was when the blade body was ground on one side.]
Agree. He should have stated that in such a good process and video. Perhaps from past sharpening it was getting close to steel on the side(?)

Have done many on the Cinci #2, tricks on the manual machine.. I have a nylon bar to hold to the side to insure the blade runs dead true to sides. For the larger 12" up depending on the use and width I would spin diameter to make true and less work at back off wheel, I wold down grind for the last .005/.010 or so to be sure no chipping from the wheel (yes the blade would kick up if not holding well)

In the video I would say they are buying top quality blades to make that time involvement prove profitable..likely they made a cost study with work quality needs and figured the use of good blades best.

I had a newspaper blade (circular knife)that I sprayed with spray starch.. some how it kept the fine news paper from sticking and gave the blade extra life. They were about 5" by perhaps 1/8 with a double bevel to a knife(razor) edge.
(yes the were a metric size as many knives are so many need a special holder).

John Welden said:

That's the kind of Youtube video I love seeing. I learned a lot, thank you.

Click to expand...

Wow John...that response is so ....unlike you. :-)
Joe

Could look close to be sure it is tight to the shaft shoulder. could strike it with a file to see if hard or mild. check it close for bugs along the corner edge. could spin it and touch it with a marker to see where high. could tap its back side lightly to if it moves easy (yes not very hard to not mess up the thrust attitude of the motor.

I would be sure it had no burrs and then touch it with my finger going the rub way(not the catch way)but would not recommend anyone to do that.

It only takes a small error to make a 1/16 wobble at the wheel diameter.












0

A lot of saw arbors just have a small shoulder on the shaft and a flange is put on with a close fit. If crud gets in the space between by carelessness during blade changes it can not only cause runout but stick the flange so tightly it appears pressed on. I would suggest trying to find a manual or parts diagram for that model online so you can see what things look like.

Joe Rogers said:

Wow John...that response is so ....unlike you. :-)
Joe

Click to expand...

Not really. 99% of Youtube videos about manufacturing and that sort of thing are by home shop retards trying to act like they've really got shit figured out. This sort of video by pros that shows how they do something the pro way is something I really appreciate.

CalG said:

run out will not "scorch the harder woods" Sap build up and dull blades will.

Click to expand...

Everyone had excellant replies, but I think that Cal has hit the nail on the head...

Dado set - Wikipedia, the free encyclopedia

Older and cheaper "Wobble" dado sets relied on this very thing. A wobble in a sharp table saw blade, with a fence set accurately to not cause any binding with the blade, will produce a wider kerf than a blade without distortion, but should not burn material. Also, if the wrong blade is used, as in using an alternate tooth bevel for ripping, as opposed to a true ripping blade; particularly in hardwoods, will likely burn the wood, no matter how sharp the blade is.

I am not disputing that there may be some problems with the OP's arbor or blade flanges, just saying that there may be other factors to consider...

Brian

Use the KISS principle; No sophisticated tools needed (but a dial indicator is sure nice.) The burning of the blade is caused by the fence not being lined up with the blade. The table may be out of alignment. Raise blade fully, mark a blade tooth and measure the miter gauge slot To marked tooth when it is closest to the front then to the back. You will either have to move the table relative to the blade or the trunions relative to the table to correct it. Depends on the design of the saw which you can do. If it is the trunions mounted to the table, it is a PIA!. Now that you have the blade true to the miter slot, adjust the fence true to the miter slot or blade. Easiest to do to the miter slot.
If the blade has been run hot it may be warped. Since you only used one tooth for alignment it won't have affected that. Even if the blade wobbles, with the blade and fence correctly aligned It should work OK. Clean the blade with some oven cleaner. Use either a dedicated rip blade (few teeth and straight grind) or a combination blade for ripping. The wobble will just make for a wider kerf and take a bit more power.

If you want to get carried away you can check the arbor and flanges. It is unlikely to be the bearings so we will start else ware. Rubber band a new magic marker to a pc. of wood that you can clamp to the table. Move the tip of the marker slowly toward the farthest out smooth part of the arbor until it just touches while slowly rotating the arbor. Replace the marker with a stick and using a feeler gage (cheap one will work fine) you can rotate the arbor 180 and see if or how bad the arbor is bent. If bent The cost of a professional fix makes the saw junk.
If arbor is OK, the inner flange is the likely issue. It is probably a close fit to the 5/8" arbor shaft and seated against a shoulder. Remove the flange, clean everything and check for burs. File off any burs. Put a known good blade on and hand rotate to check for wobble using a fixed reference. Still there? Eliminate the blade as a possible cause. Mark the shaft and blade then loosen the blade and move ONLY (Not the flange) the blade 180 in relationship to the shaft. If the same tooth remains farthest out, its the blade. If not, you are down to the flange or the shoulder on the arbor. If the flange is tight or you weren't able to push it off, check for the high spot like you did on the blade. Measure wobble with a feeler gage, same way. Some wobble there is inherent in cheap saws but shouldn't cause 1/16" @ top of blade.