SawStop false brake activation

[Eric Anderson]

I was wondering if anyone has ever experienced this. I had just changed my blade over to a dado blade, turned on the saw, and boom, the brake triggered. Nothing touched the blade and the blade never even got up to speed, so fortunately, the Dado set is probably OK, can't see any damage and since the saw never even got to speed, the damage to the blade is probably just due to carbide cutting into aluminum (little dulling, maybe). Unlike others that have talked about brake triggers, this one made no loud noise like when its fully spinning, as the set just disappeared.

I'm sending in the cartridge for testing, but SawStop Tech told me that the problem was likely the dado set was too close to the brake (it was set based on the "feeler" gauge that comes with the saw). He said when using a dado to increase the distance from the blade when using a dado blade several mm above the gauge setting. I've used the dado hundreds of times, same set up so still don't understand what happened.

I have had the saw for over 5 years (and dearly love it) and this is the first brake activation I've had. I haven't seen anyone discuss this particular issue, so thought I'd throw this out.

Thanks for any input.

[Todd Mason-Darnell]

Eric,

Just to check the simple things, you were using the dado cartridge with the dado stack?

Did you have the chippers on dado stack? I am asking because since the Sawstop works on a capacitance measurement, if the stack was on the edge of being too close, when the chippers cycled past the sensors on the brake, it could trip the mechanism (the increase in metal from the chippers will change the capacitance and fire the brake).

[sean meltvedt]

Eric, I have experienced the same issue, it was caused by the riving knife holder contacting the brake cartridge. As a cure, I made a wooden base the same thickness and shape of the riving knife, and clamp it in when I’m using dado’s or my 1/4 kerf blade. This cure has been working for at least 3 years👍

[glenn bradley]

I don't know about now with Laguna but, originally you sent the cartridge in and they verified the cause. If the cartridge were too close to the blade the saw should never have passed the power up sequence so I'm no buying that and would contest it. I read nothing in the manual for my 3HP PCS about spacing differently for a dado stack.

[Nick Decker]

Laguna? Maybe Festool?

[Wade Lippman]

Eric, I have experienced the same issue, it was caused by the riving knife holder contacting the brake cartridge. As a cure, I made a wooden base the same thickness and shape of the riving knife, and clamp it in when I’m using dado’s or my 1/4 kerf blade. This cure has been working for at least 3 years

Can you explain this more fully? How can the holder contact the cartridge?

[Chuck Nickerson]

My one false trigger happened on a very hot day when I was dripping sweat. I strongly suspect my wet hand left sweat on the board which triggered the mechanism.
Since you're in Austin and it's summer that's a consideration.

[Simon MacGowen]

Eric, I have experienced the same issue, it was caused by the riving knife holder contacting the brake cartridge. As a cure, I made a wooden base the same thickness and shape of the riving knife, and clamp it in when I’m using dado’s or my 1/4 kerf blade. This cure has been working for at least 3 years��

This is the first time I saw or heard a suggestion like this. None of the PCS and ICS I have worked with dado cutters need any special jig or add-ons to make them work. The manual has not mentioned anything like that either. I hope the SS people (forgot his name here) should clarify about that. If it is a bonus safeguard, I would copy the suggestion.

I always check the gap after changing one blade to another, dado cutter not not, just in case.

Simon

[glenn bradley]

Laguna? Maybe Festool?

Doh! Brain-fade. Yes, Festool. Thanks!

This is the first time I saw or heard a suggestion like this. None of the PCS and ICS I have worked with dado cutters need any special jig or add-ons to make them work.

Ditto, something is wrong there. When a tool is not functioning as designed, call tech support. I do buy some budget tools like Grizzly that have known hacks to improve their performance. I also buy high end tools and do not accept anything less than what I am paying for. It is our duty to make manufacturer's responsible for their products

[Nick Decker]

I've had no issues using a dado blade/cartridge, according to the instructions. Can you imagine the liability issues if there were further instructions and SawStop wasn't making users aware of them?

[Eric Anderson]

I asked them about that, because I was dripping pretty badly that day (actually had to clean and CRC the table after I was done as those salt droplets rust fast), but Sawstop said that would not trigger the brake. But the problem was it triggered without any contact with the blade. The trigger happened on startup, hit the on paddle, and the brake activated, well before any speed was even built up.

[Eric Anderson]

Todd, I was using the Freud set, with the two outer blades and three chippers and with shims set to 3/4" undersized plywood. And yes it was the dado cartridge.

[sean meltvedt]

7F3B8304-6182-4340-87BD-DA8959D45FD2.jpgSimon & Wade; if memory serves, the free side of the riving clamp would be just be able to touch the outside corner of the brake cartridge where it slides onto the large pin. I dunno if it would contact with the 10” cartridge as I always have either the knife, or the guard in the clamp��
I suppose you could get an extra knife and cut it down if you don’t want to make one from wood.
I just added the pic this morning , you can see the rub line where the clamp contacts the brake during installation and removal.

[jerry cousins]

I had the same thing happen with my dado blade - no apparent reason. Sent it to ss for analysis - no real cause - maybe faulty circuit?? They sent me a replacement. Xcellent customer service.

[Eric Anderson]

Got a update from Sawstop today. They analyzed the cartridge and got some contradicting information. Blade sensor told them the blade was at 4000 rpm, but had only been on for 0.4 ms. The tech I talked to agreed that it was pretty highly unlikely the blade was at full speed 0.4 ms after being turned on so we discussed some possibilities for the fire, one of which was noted by Sean. He said it as a low possibility, but possible that the riving knife holder (NOT the handle) could have been the trigger. He also said that it wasn't a bad idea to put a small piece of cardboard in the riving knife holder and clamp it down to keep it from "rattling". Again Sean suggested this too (or similar technique). Other than that, the tech had no ideas, but SawStop is sending a new cartridge. The tech as very helpful and the service was great. I've had some dealing with Powermatic service and they solved the problem but were not nearly as responsive. SawStop's customer service is pretty excellent. So bottom line, a misfire, and no real explanation.