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

[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.

[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.

[Lee Schierer]

One work around would be to lower the blade below the insert until the blade is up to speed and lowering it again before shutting off the power.

[Robert Hayward]

Cannot say positively it is not run out, but I do not think it is. I will pick up a dial indicator and mag base this weekend and check the run out anyway. Reason it does not look like run out to me is because the blade can be raised up through a fresh piece of wood and the resulting kerf/slot is dead straight with smooth sides. This problem occurs only when the saw is turned on and then for only a split second.

I have checked for play in the arbor, by hand, and the arbor feels tight like you would expect a new saw to be.

In a few minutes I am going out to the shop and check the belt tension. Over the weekend I had my head inside the cabinet adjusting the 90° stop bolt and casually squeezed the belt together, or tried to. It felt really tight, but that was just a touch while I was on the floor. Not a real tension check.

Do not know why, but I am thinking this is a blade problem. I have a WW11 full kerf ( 1/8") on the way, but will not be here until next week. The Ridge Carbide blade on the saw now is brand new and also 1/8" kerf. Good solid blade, in my opinion.

I will do a Google search for this, but what is the proper way to check for arbor shaft and flange run out ?

[Tom Ewell]

Needless to say, but I will anyway, remove the zero clearance insert before going to a blade angle other than 90°

Sometimes during a busy day this little tidbit goes forgotten when setting up for an angle rip...... BTDT

[Ronald Blue]

It's much more likely that the saw is causing this than the blade. That blade isn't so flimsy that the torque of start up is going to cause it to deflect sideways. I would check the drive belt tension as John suggested and maybe even experiment with it and also make sure no play is evident in the arbor bearings. Also there is no harm in truing your arbor flanges up as Matt suggested. As much as it appears it is moving I would suspect something is not as tight as it should be in the trunnion and arbor area.