Blade or table saw problem ?

[Robert Hayward]

A new PM2000 table saw, new Ridge Carbide 40 tooth blade and what was a new Powermatic zero clearance throat plate.

Each time the saw is started I get a little flutter, waver or what ever you want to call it causing the fresh cut in the zero clearance plate to widen ever so slightly. The widest being wherever the blade teeth are, then tapering back to the normal 1/8" wide kerf closer to the arbor. The happens for only a split second then the blade runs smooth and true. The plate is being cut slightly less than a 1/32" wider at the teeth. Each time the blade position is changed the plate gets cut again upon startup.


What are your thoughts, blade problem or PM2000 problem ? Or maybe normal ?

[Matt Day]

Did you check the arbor for runout and make sure the arbor flanges are flat/true?

[Myk Rian]

You need to check the blade, arbor, and flange with a dial indicator. HF has one that is suitable. Get the magnetic base for it also.
Is the raising mechanism locked?

[John Lankers]

If this only happens when you turn the saw on then I would check the drive belt/s also, if they are too tight it could cause the the arbor to twist ever so slightly. 1/2 thou on the arbor could translate into 1/64" at the saw teeth..
Btw., try a different blade first and see if that's the problem.

[David Kumm]

I don't know the probability but it could be mediocre bearings with too much internal clearance. Old English direct drive saws ran self aligning bearings of large size. Blades wobble slightly at start up until the bearing centers and then gets tighter as the bearings warm up. The little radial bearings used in new saws should not do that but if the clearance cold is too loose, you could get the same flutter until the bearing seats itself. If all else fails, that could be the problem. Dave

[lee cox]

I would buy a gauge which fits in the miter slot. I have both and prefer the miter slot version. I am no expert but I restored 3 Delta table saws. The arbor bearings have already been mentioned. Also the arbor plate. I had to have an arbor plate turned on a lathe to be square to the arbor shaft by chucking the arbor shaft in the lathe. Is that blade a thin kerf? Maybe your aero insert is a little off and bending the blade. Lots of things to check.

[Jim Dwight]

My saw is very different from yours, a BT3100, but it does this too. I think the blade goes through a harmonic during startup that causes the flutter. I haven't calculated the speed of the outer diameter but I think it's above the speed of sound. So it could just be passing through that. I don't think it's bearings or the blade. I suspect all saws do this. Bearings will not prevent all movement of the outer portion of the blade if the system vibrates. It only takes a split second to impact the zero clearance plate a tiny amount.

My "solution" is to use one zero clearance plate for normal work where it isn't critical that it really have zero clearance and to use a new one for the rare situation where I really need it to have zero clearance. I make them of scrap so it isn't a big deal. (I use a zero clearance all the time after having a cutoff fall into the little belts of the BT3100 ruining them - they are a pain to change)

[Tom Ewell]

Kinda agree with Jim, I use a glueline ripper so my 'divots' are a little smoother but still there.

Since a normally preset the hgt of the blade then turn it on, the wind up to speed usually causes some 'tinging' in the insert slot unless I'm spot on at a preset hgt which ain't going to happen.

Fresh cut inserts stay pretty good for a while but after many hours of use at different settings the slot shows some wear.

Definitely check out the specs with a gauge and make sure the blade looks good, could be even a tooth slightly miss ground or bent kicking the blade side to side too.

[David Kumm]

Jim could be on to something but I don't get anywhere near that flutter on my 18" blades. Your picture shows what I consider to be a massive flutter. I agree that all saws should have their flanges trued up. makes a huge difference. Dave

[Van Huskey]

I haven't calculated the speed of the outer diameter but I think it's above the speed of sound.

The tip speed on a 10" saw on the average table saw is probably going to be less than 20% of the speed of sound.

[John Neel]

Speed of sound is about 767 mph. Outer edge of 10 inch blade @3450 rpm travels at about 103 mph. Some 10 inch models have a blade speed faster than this, but none come close to the speed of sound. A 10 inch blade would have to spin over 25700 rpm for the outer edge to reach the speed of sound.

[Van Huskey]

Speed of sound is about 767 mph. Outer edge of 10 inch blade @3450 rpm travels at about 103 mph. Some 10 inch models have a blade speed faster than this, but none come close to the speed of sound. A 10 inch blade would have to spin over 25700 rpm for the outer edge to reach the speed of sound.

That is what I as saying earlier, the PM 2000 spins 4300 rpm but still in the 140 mph range.

[Curt Harms]

My saw is very different from yours, a BT3100, but it does this too. I think the blade goes through a harmonic during startup that causes the flutter. I haven't calculated the speed of the outer diameter but I think it's above the speed of sound. So it could just be passing through that. I don't think it's bearings or the blade. I suspect all saws do this. Bearings will not prevent all movement of the outer portion of the blade if the system vibrates. It only takes a split second to impact the zero clearance plate a tiny amount.

My "solution" is to use one zero clearance plate for normal work where it isn't critical that it really have zero clearance and to use a new one for the rare situation where I really need it to have zero clearance. I make them of scrap so it isn't a big deal. (I use a zero clearance all the time after having a cutoff fall into the little belts of the BT3100 ruining them - they are a pain to change)

I was thinking harmonic as well. Pretty good sized hunks of steel can flutter if the right things go wrong, I know of a solid steel shaft about 1/38" in diameter with high precision machining that if it runs for any period of time at certain RPMs will flutter and me$$ the bearings up. Actually that's more like me$$$$$ things up.

[Frank Pratt]

I've had 3 table saws & many blades & all have done that to some degree. Looks pretty normal to me.

[glenn bradley]

I'll assume you have already confirmed that the blade is clean, the flanges are smooth and well machined and other blades do the same thing. I you have not checked these things If would do that first.

While the blade is off you can take ahold of the Arbor and try to move it laterally to see if there's any play in the bearings, any sort of a ticking feel. Let us know how that turns out and will move along.