My SawStop may have just injured itself!

[Stephen Roth]

I was using the SawStop (Industrial Model) with a Systematic Dado blade. (8" with all cutters installed.) The aluminum miter gauge hit the blade and WHAM!, the trigger activated. I have had the trigger activate before when I forgot that there was metal involved (such as cutting aluminum foil coated foam insulation), but this activation seemed much kinetic. In fact, the brake got shredded and sheared off teeth from the dado blade. Not just the carbide -- the actual teeth. (See pics.)

I figured I would check the alignment of the blade to the miter gauge, and found that it was out of alignment by .011" I usually can align the saw to .001, so I realigned it with an alignment plate and got it back to .001. But when I put on a blade, I found out the alignment was still out .007, depending on how I rotated the blade. For example, +.005 and then rotated 180 degrees and out by -.002. And the reverse in another 180. So I figured I would check the runout of the arbor flange, which the factory specs list as having a .001 tolerance. Mine was now .002. That does not seem like a lot, but taking the radius of the flange out to the edge of the blade would increase it at least 3-4 times, which translates to a .007 wobble in the blade plate.

Also, the cut quality is certainly inferior to what it had been before. Previously, I could get a glass smooth cut-off with a Forrest Cross-cut blade, and now I can see tooth marks. Also, the saw makes a slightly different sound. Like there is more vibration.

I called SawStop, and they say the tolerance for blade wobble is .010 and that I should not have used a dado with full cutters. (Note that they only recently recommend this practice, probably because the saw cannot stop a spinning billet of 8" x 3/4" metal.)

I can't believe .010 wobble is acceptable, especially when the SawStop manual describes that you can get to .001. And .010 is bad. Darn, I can measure .010 without a dial indicator. SawStop said the flange run-out was over spec, but not bad. This is where I got into a debate with the rep as to whether .002 was only a thou. more than .001, or was double .001!!!

So here are my questions:

1. Do others regularly get blade/mite slot alignment close to .001. I can't believe that 10 times that (i.e. .010) is within tolerance for this type of saw.

2. SawStop said I could replace the arbor assembly for $250. Has anyone else replaced that part? Seems like it would be a bear. (FYI, it upsets me that SawStop would not send that to me a this seems like a problem that they did not know to tell people about until it arose.)

Thanks in advance. IMG_3540.jpgIMG_3542.jpgIMG_3541.jpg

[Joe Rogers]

This is what I call being on the expensive end of the learning curve. You state you have had several brake events. The problem with the saw stop activation is it is a “cost of doing business”. It is a shame that current recommendations against a stacked dado arrived post activation. That said, any activation has a cost attached and this one is real expensive. I wish that Saw Stop would help out here by offering the arbor at a significant discount due to circumstances but if not I guess I would still replace it on my dime and in the future be EXTREMELY careful with any metal near the saw blade.
Joe

[Kevin Jenness]

Sounds like you need to replace the arbor- too bad. Maybe if you complain farther up the chain SS will reduce the price. Still, between a new arbor, brake and dado set an expensive error. If it were skin contact the repair would seem quite cheap. As is, well, you'll probably remember to keep metal out of the blade in future.

[David Utterback]

"that I should not have used a dado with full cutters."

Could you please explain what kind of cutters these are? Thanks

[mike stenson]

A full dado stack? That's a lot of mass rotating, and a lot grabbing at the stop. I'm not surprised that something else had to give.

[Stephen Roth]

So there are two types of dado stacks. Both use full saw blade plates on the outside. The expensive ones also use full plate blades for the cutters on the inside that stack up to make the width of the cut you want. The less expensive ones (and the ones that SawStop now recommends) has what are called "wing cutters." These use rectangular insert plates that have less metal and reduce the weight of the stack. Here is what SawStop says ...

"SawStop recommends only using 8” stacked dado sets, with a maximum thickness of 13/16”. “Wobble” dado sets are not recommended, as they may not engage correctly with the dado brake cartridge. Do not use dado sets with solid-plate interior chippers or blades with molding heads, as neither brake cartridge is designed to stop those blade types."

[Stephen Roth]

Yes, it is an expensive error. But I'm happy that the saw has this feature. In fact, I bought the saw when I started working with my 12 year old son and his friends in the shop. I told my wife that if the whole saw had to be replaced when it saved cutting off some kid's finger, it would be worth it.

[Frank Pratt]

So there are two types of dado stacks. Both use full saw blade plates on the outside. The expensive ones also use full plate blades for the cutters on the inside that stack up to make the width of the cut you want. The less expensive ones (and the ones that SawStop now recommends) has what are called "wing cutters." These use rectangular insert plates that have less metal and reduce the weight of the stack. Here is what SawStop says ...

"SawStop recommends only using 8” stacked dado sets, with a maximum thickness of 13/16”. “Wobble” dado sets are not recommended, as they may not engage correctly with the dado brake cartridge. Do not use dado sets with solid-plate interior chippers or blades with molding heads, as neither brake cartridge is designed to stop those blade types."

They've been including that in their manual for at least as long as I've had mine, about 5 years.

[Frank Pratt]

I tripped mine once when cutting a board with some graphite cloth glued to it It also took a couple of teeth from the blade disk.

[Brian Holcombe]

Most likely bent the arbor. I can’t imagine these operate without bending the arbor.

.010” wobble is terrible, should be negligible IMO.

[Jim Dwight]

I am a bit confused about the difference between your dado set, the one that was damaged, and what SawStop recommends. I looked up Systematic dado sets and the picture shows simple wing, two tooth, chippers (outside blades differ in tooth count for two different models). But you seem to describe interior blades I am calling chippers as full blades. Did Systematic made a different set previously?

I do not doubt that the effect of the cartridge activating on a dado blade was more violent but any cartridge activation is violent. I also think the effect may have been cumulative.

I don't know anything about the arbor but before I spent $250 for a new one I would look into bearing replacement. The arbor could be bent but I doubt it. Seems more likely to me that the bearing might be damaged. The repeatability you describe, however, works against this theory. If you can get the arbor out and roll it on a flat surface it would tell you.

[Stephen Roth]

I agree. I can't believe SawStop says a .010 blade misalignment is within tolerance. In fact, when I said that, I responded "INCHES! You must mean milimeters!"

[Corey Pelton]

When I bought my PCS a couple years back, I was having trouble getting the blade aligned to the miter slot. I figured the blade was out of whack. I threw on every blade I had, and it still gave the same error on the opposite side of the blade. After chatting with SawStop support, they surmised the arbor had an issue. They shipped me out a new arbor block. After installing the new arbor block, the issue was gone. Bit of a pain in the ass, but all's well that ends well.

[Ben Rivel]

So there are two types of dado stacks. Both use full saw blade plates on the outside. The expensive ones also use full plate blades for the cutters on the inside that stack up to make the width of the cut you want. The less expensive ones (and the ones that SawStop now recommends) has what are called "wing cutters." These use rectangular insert plates that have less metal and reduce the weight of the stack. Here is what SawStop says ...

"SawStop recommends only using 8” stacked dado sets, with a maximum thickness of 13/16”. “Wobble” dado sets are not recommended, as they may not engage correctly with the dado brake cartridge. Do not use dado sets with solid-plate interior chippers or blades with molding heads, as neither brake cartridge is designed to stop those blade types."

Is the Forrest Dado King not considered an expensive one? Because it comes with the "chipper" inner blades, not full sized ones.

[Wade Lippman]

..

"SawStop recommends only using 8” stacked dado sets, with a maximum thickness of 13/16”. “Wobble” dado sets are not recommended, as they may not engage correctly with the dado brake cartridge. Do not use dado sets with solid-plate interior chippers or blades with molding heads, as neither brake cartridge is designed to stop those blade types."

I bought my SS about 7 years ago and I am reasonably sure that was their recommendation back then.