How much blade wobble is OK?

[Bill Reed]

Having bought a set of new blades for my new Felder K700 saw, I installed one and noticed that I could see it wobble slightly as it braked to a stop. I got out my Oneway gauge and measured the wobble at the outside of the 315mm blade just inside of the carbide teeth. There is a .01" (ten thousandths of an inch) difference between the high spot and the low spot. I then measured two other blades and got about the same results. I am pretty sure it is not due to arbor runout, since the high and low spots are at different positions on different blades and are not necessarily 180 degrees opposite each other. Is this typical of most blades, and is it acceptable?

Bill

[Bill Reed]

Sorry for the confusion. I really meant to say ten one-thousandths of an inch, i.e. one hundredth of an inch.

Bill

[Terry Browne]

I'm not an expert, but as a general rule anything less than .015 is acceptable. However, less is always better.

[Ken Fitzgerald]

IMHO....realistically...wood is dynamic not like metal. I doubt that much of the time my tools will cut closer than 0.015"....and the wood itself can move/warp/twist/bend that much from released internal pressures and finish drying.....JMHO.

[David DeCristoforo]

You need to keep in mind the fact that most saw blades have some degree of "static warp" that will "flatten out" at operating speed. The best way to test a blade (or saw) is to make a cut. If the cut clean, the measured "runout" of a few thousandths is pretty much moot. If the cut is ragged or the stock burns or there are any other issues, then it's time to look for alignment or runout issues.

YM

[Tom Henderson2]

Hi BIll-

What is the lateral runnout (flange wobble) at the flange itself?

Measuring at the blade rim is often misleading, as others have pointed out.

-Tom H.

[Cliff Rohrabacher]

Whose blade are you using?

your blade is out 0.010" is that TIR (total indicator readout) or is that splitting the difference?


I am most certain it isn't the machine.

[Bill Reed]

Whose blade are you using?

your blade is out 0.010" is that TIR (total indicator readout) or is that splitting the difference?


I am most certain it isn't the machine.

Cliff,

I sorry I don't understand your question. I place the indicator on the table just touching the face of the blade just inside the teeth. Rotating the blade by hand, I take several readings around the blade. I find a variation of about .01" between the maximum and minimum readings. Typically, what I might see on my indicator dial are readings varying between 80 thousandths and 90 thousandths. Is this helpful?

Bill

[Phil Thien]

First advice would be to remove the blade and clean the flange, threads, washers, and nut with a toothbrush and maybe some 409 or something. I'd suggest solvent but you don't want to drip any on your saw.

I believe a saw of your caliber should be able to achieve .003". I know my Ryobi BT3000 (the butt of many jokes) can and does.

[Tom Henderson2]

Cliff,

I sorry I don't understand your question. I place the indicator on the table just touching the face of the blade just inside the teeth. Rotating the blade by hand, I take several readings around the blade. I find a variation of about .01" between the maximum and minimum readings. Typically, what I might see on my indicator dial are readings varying between 80 thousandths and 90 thousandths. Is this helpful?

Bill

What you are describing is known as "Total Indicated Runnout" or TIR.

But what runnout to you measure at the arbor flange? That is what you really want to know....

-Tom H.

[Walt Stevens]

I have a Forrest WWII on a Grizzly 1023. Total indicated runout on the arbor flange is less than 0.001. TIR of the blade (just inside the teeth) depends on the rotational position of the blade relative to the arbor flange, because the blade runout and the arbor runout (multiplied by the blade diameter) can add or cancel somewhat. I have rotated the blade relative to the arbor at 60 degree intervals and remeasured the TIR. The maximum I've measured is 0.009, and the minimum is 0.004. I left it in the 0.004 position for subsequent tests. I suspect the blade is not as flat as the 0.001 Forrest claims in their specs, and they have offered to replace it. However, it cuts extremely well and leaves beautifully smooth surfaces, so I decided to keep it. The experienced members of this forum will tell you that the performance in actual applications is more important than static measurements in the thousandths of an inch.

[Bill Reed]

What you are describing is known as "Total Indicated Runnout" or TIR.

But what runnout to you measure at the arbor flange? That is what you really want to know....

-Tom H.

Tom,

Yes, I would like to know the runout at the arbor flange. But this is very hard to measure on a Felder saw, which has two pins that protrude from the flange and interfere with the dial indicator. I haven't figured out how to take this measurement yet.

Bill

[Jacob Reverb]

I'm with Ken and Walt, and would just cut wood with the machine and see if the results are acceptable. In woodworking, I think there's a time for dial indicators ... and a time to put dial indicators away and saw wood.

There are just so many variables and the tolerances are probably a lot greater than we need to worry about more often than not, and you can drive yourself crazy with dial indicators measuring the thickness of rust flecks and sawdust molecules...then again, I'm sure my work is a lot more Potlatch than most! :p

[Al Willits]

If I remember right, I had a Freud blade that was a bit off and I believe the Freud rep posted or emailed me that .003 was either to much or max. I had about .08 or something like that, and I ended up taking the blade back and replacing it.

Al...who hopes he has the decimal in the right place...:)

[Tom Walz]

0.003" max on a Big Box blade
0.0015" on a pro shop blade
0.0005" on a precision thin kerf

[John Thompson]

What problems were you having with the actual cut "before" you picked up the dail calipers?....

As already so wisely stated by Ken.. Walt and Jacob, if the answer is none to that question.. I would put the dial calipers back in the box and wait till you pick up metal-working as a hobby. I doubt you will find dial calipers in the shops of any professional that does this for a living. I can say for fact Ian Kirby.. Richard Jones.. Ray Pine and Lee Grindinger doesn't have one and probably won't.

BTW... I have noticed on the 4 TS's I have owned since 1972 that when a blades slows down after you hit the kill switch, there is what appears to be a slight amount of wobble before it stops on occasion. I have encountered no problems from that and personally believe it to be an optical illusion as I seem to see it only when viewing the blade from certain angles.

Regards...

Sarge..

[Tom Walz]

The body of a saw blade is not really a rigid piece of steel. It might also be considered as a very carefully engineered steel spring.

Saw blades are somewhat like a weight on the end of a string. The end of the string travels faster than the part near your hand. If you stop twirling suddenly the string ripples and collapses.

The outside of a saw blade travels faster than the bore does. The outside wants to grow which is why you have expansion slots on the rim.

Saw blades also have a harmonic properties. If you tap one it will ring. As a saw blade spins faster and faster it can reach a ‘critical speed” which is where it starts to wobble. As it spins faster it can reach a point where a second wobble develops and the saw blade starts to wobble in two places and “potato chip.” This is important because saw speed relates to feed rate.

[Lee Schierer]

Just for curiosity after reading this thread, I set up a dial indicator on my 20+ year old Craftsman table saw. Without cleaning the blade or mounting flange the blade had a total run out just below the gullets of .0035" or +/- .00175" Then I removed the blade and cleaned the blade and flange with some scotchbrite so there was no dirt sticking to it. The reading was .004" total or +/- .002". The blade was a Freud LU82M010. This is one of their laser cut noise dampened blades. I think I paid less than $40 for it.

All in all I would say the blade is pretty flat and the arbor runs pretty true.