SawStop Brake Misfire Due to Faulty RPM Sensor?

[Mike Shields]

I'm curious if any SawStop owners have experienced this type of failure:

saw has power, but the blade has not spun for minutes, touch the blade and the brake actuates. The manual specifically states that the brake should not fire if the blade is not spinning. The SawStop has an RPM sensor so that the safety feature still functions after the STOP has been hit, but the blade is still spinning.

I had a dado blade & brake installed, and was adjusting a MDF fence for cutting a tenon. I heard a pop, and thought I saw the blade drop. Looked inside and saw the brake against my $300 Forrest dado. Ugh!

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After some struggle, I got the brake removed, then the blade; boy was I worried about the stack! Fortunately, there was no damage.

With quite a bit of hesitation, I bought a new brake at the local woodstore and installed it; the saw is running great.

Bad brake, or faulty RPM sensor? Won't really know until I can contact SawStop on Monday.

Mike

[Clay Fails]

I have the ICS, and fortunately have nit had that issue (yet). Keep us posted on your situation.

[Kevin Womer]

I have not had a brake activation and have had the saw for over a year on a 3hp PCS. I have used dado set and cartridge fairly often. Sorry to hear of you dado set, maybe it can be sent to Forrest and repaired. Keep us posted.

[Larry Frank]

I hope that you will post the answer from SawStop.

I had the cartridge on my SawStop fire this week and it was the result of my stupidity. I was cutting with the blade tilted 45° and it just nicked the edge of my Incra miter gauge. So it was the cost of a cartridge and the blade. Luckily, it was an older rip blade and one of the cheaper ones that I have. The blade had 6-7 of the carbide teeth damaged and most half gone. I am going to hang a big picture of this in my shop to remind me not to do it again.


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[Bob Michaels]

Yeah, what Larry said. I've got a trophy like that too.

[Dale Murray]

I am in the market for a saw and potentially considering a sawstop though the extra grand+ for the ICS is a bit daunting. I will follow this thread to see how they resolve/explain this.

[Jim Barstow]

Looks just like my trophy to stupidity, too. I wonder what the ratio of "fired due to flesh contact" vs "fired due to stupidity" is? (Although one might argue that "flesh contact" is, by definition, a subset of "stupidity".)

[Mark Blatter]

I am in the market for a saw and potentially considering a sawstop though the extra grand+ for the ICS is a bit daunting. I will follow this thread to see how they resolve/explain this.

I used a Sawstop at a past job and frankly would not buy anything else. Too many things just happen and having the added protection of the Sawstop is just worth it for me. I hope to have the money to replace my TS in the future. $1000 is just so much cheaper than a $25,000 hospital bill.

[Mike Shields]

Here is a better picture of my dado brake. You can see where the blade cutters hit between the words BLADE and TO, and after the word GAP on the = sign. It should be obvious the blade was not spinning. What is interesting is the lack of any significant damage that others are showing when they've had brake fires. The dado blade, thank goodness, has zero damage. (lucky me for a change)

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[johnny means]

I wonder if its possible that the saw sensed some sort of anomaly that caused it to be unsure of RPM. Then it would make sense for the software to react to a worst case scenario and assume the blade was rotating. Such redundancies and backups would ensure safety if certain parts of the system failed.

In this scenario I would consider this triggering a good thing. Better rhan it not firing when there is a problem.

[mreza Salav]

Talk to Sawstop. They have the best customer service I've experienced. Probably they'll ask you to send the brake and will analyze it.

[Steve Gojevic]

Here is a better picture of my dado brake. You can see where the blade cutters hit between the words BLADE and TO, and after the word GAP on the = sign. It should be obvious the blade was not spinning. What is interesting is the lack of any significant damage that others are showing when they've had brake fires. The dado blade, thank goodness, has zero damage. (lucky me for a change)

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The significant damage to the blade occurs when the spinning blade buries itself into the metal brake. Since your blade wasn't spinning, I would not expect much damage. The brake module has a compressed spring that is held compressed until a "fuse wire" burns off and the spring releases its energy and pushes the brake against the blade. If the blade is spinning, it digs itself into the brake and stops the blade, usually within a few teeth.

Steve

[Keith Hankins]

I am in the market for a saw and potentially considering a sawstop though the extra grand+ for the ICS is a bit daunting. I will follow this thread to see how they resolve/explain this.

I'm getting ready to pull the trigger on the ICS 5hp. I wish they had the pcs in 5hp. Anyway even if there is a bad part, does not change my mind. I don't see it being systemic issue.

[Myk Rian]

I have not had a brake activation and have had the saw for over a year on a 3hp PCS. I have used dado set and cartridge fairly often. Sorry to hear of you dado set, maybe it can be sent to Forrest and repaired. Keep us posted.
The stack is OK.

[Kevin Womer]

The stack is OK.

Should be checked out carbide is brittle and can crack.

[Tim Davis 1947]

My ICS has fired the dado brake from a piece of carbide that chipped off and went to ground. It appears the carbide chipped when on of the chippers banged into the carbide tooth. My bad for not making sure the dado blade was not tight enough.

[Mike Heidrick]

I don't think Sawstop recommends permashield red blades either. I'd avoid coated blade.

[Daniel Smith]

A couple of years ago, I had my dado brake fire right as I turned the power on. Sent it back to SawStop and was told that it was due to some sort of computer glitch. The service was excellent and they replaced the cartridge at no cost to me. Fortunately, my dado stack had barely started moving so no damage was done. As with several others in this thread, I have trashed a rip blade from contact with a metal mitre gauge.

[Steve Rozmiarek]

Just a casual observation, it's interesting how many people posting to this thread have had a misfire or a activation of the brake because of something other than flesh contact. I don't remember seeing anyone posting here that the saw fired from flesh contact. Maybe we're more careful than we thought?

[Tom Willoughby]

Just a casual observation, it's interesting how many people posting to this thread have had a misfire or a activation of the brake because of something other than flesh contact. I don't remember seeing anyone posting here that the saw fired from flesh contact. Maybe we're more careful than we thought?

I've seen enough "flesh contact" stories to be happy to have my 3 hp PCS. Having said that, however, I've only tripped the sensor when trimming off the bottom of a box attached with brad nails. I should have known to turn the sensor off but didn't. The good news was that it was a jobber blade so I didn't trash a "good" blade.

Tom

[Dan Lee]

Freud blades with permashield are fine per their tech suppot

[Mike Shields]

I contacted SawStop this morning. The gentleman I spoke to is suggesting it's a faulty brake cartridge, hence the reason why the replacement I put in, did not fail. Once they receive my damaged one, they will replace it at no charge.

All is good!

Mike

[fernando guerrero]

sorry to hear that, but the fire with the incra sure brought back memories of my first scare. I was using the incra1000hd close to the blade and i heard a POP. but thought nothing much and my pc of wood was stuck on the overarm dust collector and I just couldnt push my wood past it until I realized the machine stopped. basically what happened was your hand and the metal on the incra arced to the blade and caused the cartridge to fire. Which sucks but was funny just thinking about it. Ive had misfires right at start up which SS replaced the paddle switch. I also had wobble on the blade thinking maybe it was the blades which was me running full 4x8 sheets and hitting them. SS sent me a new arbo and bearing to replace becaue they thought i had misaligned it. theyve sent me new fence guides all free of charge, having misfires or just bad luck sometimesis a user error. But Im glad I bought mine. Although I bought the 36" 1.75 pcs I sometimes wonder I shouldve bought the 3hp instead. in which im happy with it. And yes best customer/tech support.

[glenn bradley]

I contacted SawStop this morning. The gentleman I spoke to is suggesting it's a faulty brake cartridge, hence the reason why the replacement I put in, did not fail. Once they receive my damaged one, they will replace it at no charge.

All is good!

Mike

That's just how it is supposed to work; good deal. My only cartridge firing was after I first got the saw and naively cut something with a foil tape strip attached. Like others, I hung my cartridge and blade 'sculpture' on the wall as a reminder.

[Raymond Fries]

At least it did not fail the other way and you got injured because it did not stop the blade. Hope SawStop gets you fixed up.

[Bob Michaels]

Yeah, what Larry said. I've got a trophy like that too. Need to clarify that it was my stupidity that caused it to fire. I was trimming a board that had not completely dried from latex primer. Never have had an issue with that saw. I got one of the original 5 hp models and absolutely love it. Aside from the obvious safety features is the fact that it is a very high quality saw compared to other non-sliders. There are many items on the saw that can be tuned to really provide great operation and precision.

[Andy Pratt]

My understanding was that the freud coated blades are fine to use with the sawstop due to the arbor hole not being coated and therefore providing conductivity from the teeth to the electronic system. Someone please correct me if I am wrong. I've been using a sawstop for 6 years now, nearly every day, with probably at least a hundred or two blade swaps and haven't had an issue like this, so I'm guessing something was not working right with your cartridge/electronics.

[Andy Pratt]

Just went down to the shop and confirmed that (with the blade stationary), the "contact detected during standby" lights come on when I touch the red coating (and only the red coating) on my freud blade with my finger. In other words, the red freud blade behaves just like a bare steel blade, so they should be fine to use.

[Dale Murray]

Does Sawstop offer to repair or replace a blade that is damaged due to misfire - as in the case that started this thread? Just curios.

[Bob Falk]

I have an ICS and have had one misfire....my fault.....I was cutting an old picture frame that had metallic paint......IHMO, a firing like this is reassurance that the system is working as it is designed to.....

[Art Mann]

I have probably read thousands of Sawstop threads where the brake activated when there was no safety risk and this is just about the first time I have heard of a defective brake cartridge. It seems to me that their stuff is pretty reliable. I worked in a manufacturing plant where product failure could very well lead to death. In spite of all the money we put into product safety and integrity, we got bad product going out the door occasionally. Perfect manufacturing just isn't a realistic expectation.

[Mike Heidrick]

Was the light solid green when touched? The light flashes green when the paddle is off and the saw is coasting to stop. I know it was said it had not run for minutes - I would just like to know the state of the green light. When the paddle is off and the green light is solid, when you touch the blade it will flash showing you it would have fired had it been running.

[Dale Murray]

I have an ICS and have had one misfire....my fault.....I was cutting an old picture frame that had metallic paint......IHMO, a firing like this is reassurance that the system is working as it is designed to.....

Would you feel the same about the airbag in your car?


I asked the reimbursement question because I am considering the saw and was curious. I would be really upset if there was a true misfire that cost me hundreds due to having a blade repaired or replaced.

[johnny means]

I had a dado blade & brake installed, and was adjusting a MDF fence for cutting a tenon. I heard a pop, and thought I saw the blade drop. Looked inside and saw the brake against my $300 Forrest dado. Ugh!


The blade wouldn't drop if it weren't spinning. The saws don't have any mechanism that causes the blade to drop. The blade falling below the table is a product of its own centrifugal force.

[Duane Meadows]

The blade wouldn't drop if it weren't spinning. The saws don't have any mechanism that causes the blade to drop. The blade falling below the table is a product of its own centrifugal force.

Hmm... then there must be a "mechanism" to prevent it falling? Otherwise, how can it cut? Sounds like semantics to me:rolleyes:.

It may need the centrifugal force to fall, but has to be a bit more to it than that.

[Andrew Pitonyak]

Does Sawstop offer to repair or replace a blade that is damaged due to misfire - as in the case that started this thread? Just curios.

Drop them an email and ask them... They are known for great customer service...

[Daniel Smith]

Hmm... then there must be a "mechanism" to prevent it falling? Otherwise, how can it cut? Sounds like semantics to me:rolleyes:.

It may need the centrifugal force to fall, but has to be a bit more to it than that.

It's been a while since I've had an incident so this is from memory, but I think that the drop mechanism is a combination of centrifugal force and the blade being uncoupled from the lift mechanism. Getting the fused blade/brake combo out of the saw is challenging. While doing that, I remember being able to manually lift the blade/arbor back up to height where it locked in place (in other words, I didn't have to crank it back up). There is plenty of resistance in the motion so that free fall is not an issue when the cartridge triggers.

[Duane Meadows]

Thanks Daniel, that makes more since!