Sawstop - amazing video

[Rick Levine]

I did a quick search on the SMC and didn't find a link to this so here goes. You've got to see this! Scroll down to "SawStop Inventor Walks the Walk"

http://finehomebuilding.taunton.com/item/8228/sawstop-inventor-walks-the-walk

[george wilson]

Great video! Gives us an idea of what happens if a finger should touch the blade at a fair rate of speed,like the frank did. I can't help wondering,from looking at the slow speed video of the blade and brake,how much damage might this 1/000 second stop do to the arbor? It looked like the arbor moved some. Also,the rod that the brake is mounted on moved a fair amount also.

[Chris Harry]

I guess thats really putting your money where your finger is :)

Neat video. Love the technology behind it, just cant afford one (yet)

[Rick Levine]

It is interesting that they say it is only $60 to replace the parts. I had heard earlier that it was about $200. Whatever it is I still think I'll stick with my Delta cabinet saw and push sticks as well as other aids to help move the wood across the blade.

[Chris Harry]

It is interesting that they say it is only $60 to replace the parts. I had heard earlier that it was about $200. Whatever it is I still think I'll stick with my Delta cabinet saw and push sticks as well as other aids to help move the wood across the blade.

I heard that in the video too. I was under the impression it was fairly expensive to replace the cartridge.

Maybe they meant it costs them 60.00 to make the 200.00 part :)

[Brad Wood]

remarkable. I don't think I could do it, even knowing that it would stop.

[Gary Benson]

$60 is to replace the cartridge, however, your blade is usually toast (notice the flying carbide teeth), add $80-120 for a new blade. That is the $200 price tag most people quote.
Gary

[jason lambert]

Depends I triggerd the brake and the woodworker blade was fine. I wanted to replace it but had it checked and no damage. Sawstop even gave me a brake. I think if it is a real trip and you send in the brake and they can prove it they give you a break right now. They want it so they can get real data I was told so in theory it cost me nothing. worst off it may have cost me a blade. I have to say overall I am more comfortable using this saw I am alwas very careful but you never know.

[Rick Gifford]

I like that Time Warp show.

To be fair, he slid his finger into the blade about as slow as he could. In reality you hand would be moving faster, and maybe quite fast if it was thrown over by a peice of wood.

I have heard if your hand is going into the blade at a faster speed it could still cut up to 1/8" or little more.

I grew up with a buddy that had half length fingers on his left hand because of a table saw.

We dont try to be careless, but sometimes things go wrong.

I'll take a 1/8" cut over loss of fingers any day.

I really need this on the bandsaw. I have cut myself there more than anything...

[James Williams 007]

We have well tested my dads sawstop and it works! We didnt intetionally test it but hey its nice to know it works as advertised. The saw still works like the day we unwrapped it but it took a little force to remove the brake and blade after it went off. When I graduate and pay off my student loans I am putting my jet up for sale and buying one, not only for the safety but also because of the quality.

[Don Bullock]

Depends I triggerd the brake and the woodworker blade was fine. I wanted to replace it but had it checked and no damage. Sawstop even gave me a brake. I think if it is a real trip and you send in the brake and they can prove it they give you a break right now. They want it so they can get real data I was told so in theory it cost me nothing. worst off it may have cost me a blade. I have to say overall I am more comfortable using this saw I am alwas very careful but you never know.

First of all, Jason is correct. In the handbook that comes with the SawStop it states that in the brake is triggered by flesh that it should be sent to SawStop so that they can download the data stored on a chip. If the brake was in fact triggered by flesh the new brake will be sent out free. For me that sounds like a very small price to pay for saving fingers.

Yes, this video and information has been posted before. It's important, however, to provide truthful, unbiased information on this forum so that people who may be interested is the SawStop technology can make their own decision. For me it was a simple one to make. I showed my wife some of the videos on the SawStop website and she told me I had to buy one. Even more importantly, she found a way for us to "afford" one. I have no regrets. It's a fantastic saw and it reminds me to work safely in my shop no matter what I'm doing.

[David DeCristoforo]

Here's what I had to say about that video:

"By now everyone has heard about the SawStop blade breaking system and seen the demo that they do with the hot dog. And everyone pretty much understands that this is a revolutionary breakthrough in table saw safety. The debate over whether or not this technology should be mandated (think seat belts and air bags) is far from over.

But there is a new video on You Tube in which a gentleman demonstrates the SawStop brake, not with a hot dog but with his own finger. When I saw this I cringed. The guy actually stuck his finger into a running saw blade. Am I the only one who is shocked by this? I hope not.

Confidence in your product is one thing but this is just plain foolish. It’s just asking for it. After all, this is an electro mechanical device and, sooner or later, somewhere, somehow, it’s going to fail to work properly. It would be tragic if that time just happened to be the time some guy who had seen this video was showing his friend how amazing his new super safe table saw was. Or to some guy who has been lifted to new levels of overconfidence by virtue of having seen this demonstration.

Personally, I would love to own a SawStop machine. And there is not much I wouldn’t give to have been working on one a few years back when it probably would have saved me from a serious injury. But I am amazed that they would publicly demonstrate this technology in such a manner. At least it should have a “don’t try this at home” caveat emblazoned across the screen in huge red letters."

[Wilbur Pan]

I have heard if your hand is going into the blade at a faster speed it could still cut up to 1/8" or little more.

I once did a back of the napkin calculation on how deep you could cut yourself on a Sawstop. Here's what I came up with:

The SawStop system stops the blade in 5 ms. My wrist is 3 inches wide. If I was to deliberately chop off my hand on a SawStop, I would have to get those 3 inches through the blade in 5 ms.

If you do the math, you'd have to be hitting the blade at 34 mph to do this.

Now let's look at the scenario of getting hit in the stomach with a piece of wood from kickback and falling face first on the blade. For the average person, there's about 3 feet of vertical distance between your head and the surface of the tablesaw.

Suppose the force of the blow was such that you immediately passed out, and you had a dead fall onto the blade. If you drop an object, it takes 0.45 seconds to fall 3 feet. In this time, you'll accelerate to a speed of 4.4 m/s. This works out to 9.8 mph -- much slower than it would take to chop off my wrist on a SawStop. At that speed, you'll travel into the blade only 0.8 inches in the 5 ms it takes to stop the blade. That's still a bad cut, but much better than the alternative. Realize that this estimate of the depth of the cut is exaggerated. The blade will be braking as it slows down in that 5 ms, so that the amount of time that the blade is traveling at a speed sufficient to cut human tissue is even less.

Let's take an even more ridiculous scenario. Let's suspend a woodworker from the ceiling of his shop and drop him directly on a SawStop. In order to chop off a hand at the wrist, he'll have to be going 34 mph when he hits the blade. In a dead fall, it will take him 1.5 seconds of free fall before he reaches that velocity. A dropped object will fall 39 feet in 1.5 seconds. This means that you would have to drop a woodworker from a height of 39 feet onto a SawStop before he develops the velocity needed to chop off a hand at the wrist.

(This is, of course, assuming Earth gravity. Someone else can do the math for woodworkers on Jupiter. ;) )

Now, this is likely an overestimation of a real life collision because it assumes that the blade cuts equally efficiently from the beginning to the end of that 5 ms period. Because of braking and the dropping of the blade under the table surface, the effective contact time will be less. In any case, it's much better than doing a dead fall onto a Unisaw.

[Robert Reece]

As slow as he was creeping into the blade, I am wondering if he even touched the blade. At some point the gap between his finger and blade would be small enough to conduct current. No doubt it's quite a small gap. I'm also not suggesting I would have done it at full speed.

[Mike Heidrick]

Wilbur

For sake of rhetoric....

What about the rate at which the blade drops away below the table once activated?

Also what resistance value are you assuming when cutting off a wrist? Bone is more resistant than flesh?

Also the spinning blade will try and push the wrist away and thus slow it down. Does the speed account for that?

I have seen various speeds in the hotdog tests and they have thus far not made a significant difference in the cut depth. They have all been minor knicks at most - not even a gash. Worst was when the hot dog was literally thrown at the top of the blade and it hit the riving knife before the blade.

[Sean Ackerman NY]

I once did a back of the napkin calculation on how deep you could cut yourself on a Sawstop. Here's what I came up with:

The SawStop system stops the blade in 5 ms. My wrist is 3 inches wide. If I was to deliberately chop off my hand on a SawStop, I would have to get those 3 inches through the blade in 5 ms.

If you do the math, you'd have to be hitting the blade at 34 mph to do this.

Now let's look at the scenario of getting hit in the stomach with a piece of wood from kickback and falling face first on the blade. For the average person, there's about 3 feet of vertical distance between your head and the surface of the tablesaw.

Suppose the force of the blow was such that you immediately passed out, and you had a dead fall onto the blade. If you drop an object, it takes 0.45 seconds to fall 3 feet. In this time, you'll accelerate to a speed of 4.4 m/s. This works out to 9.8 mph -- much slower than it would take to chop off my wrist on a SawStop. At that speed, you'll travel into the blade only 0.8 inches in the 5 ms it takes to stop the blade. That's still a bad cut, but much better than the alternative. Realize that this estimate of the depth of the cut is exaggerated. The blade will be braking as it slows down in that 5 ms, so that the amount of time that the blade is traveling at a speed sufficient to cut human tissue is even less.

Let's take an even more ridiculous scenario. Let's suspend a woodworker from the ceiling of his shop and drop him directly on a SawStop. In order to chop off a hand at the wrist, he'll have to be going 34 mph when he hits the blade. In a dead fall, it will take him 1.5 seconds of free fall before he reaches that velocity. A dropped object will fall 39 feet in 1.5 seconds. This means that you would have to drop a woodworker from a height of 39 feet onto a SawStop before he develops the velocity needed to chop off a hand at the wrist.

(This is, of course, assuming Earth gravity. Someone else can do the math for woodworkers on Jupiter. ;) )

Now, this is likely an overestimation of a real life collision because it assumes that the blade cuts equally efficiently from the beginning to the end of that 5 ms period. Because of braking and the dropping of the blade under the table surface, the effective contact time will be less. In any case, it's much better than doing a dead fall onto a Unisaw.

Good stuff, thanks Wilbur!!

[jason lambert]

My guess is yes current will jup through air if close enought, if you look he even wets his hand first. I don't think the blade touched him maybe very little if it did at all. Amazing technology that it doesn't go off in wood. Anyhow I don't think there is any debate there is no negitive to the saw or safety beyond price.

[Mike OMelia]

..
But there is a new video on You Tube in which a gentleman demonstrates the SawStop brake, not with a hot dog but with his own finger. When I saw this I cringed. The guy actually stuck his finger into a running saw blade. Am I the only one who is shocked by this? I hope not.
..."

If you do some searching, you can find the videos of the guy who inveneted the lightweight kevlar bullet proof vest. He literally pointed a 38 at himself and pulled the trigger. It knocked him over, and knocked him silly. However, when he showed it to potential buyers, the video spoke volumes. Crazy? Perhaps. But when you tell a person this thing will save your life (finger), actions speak louder than words. When SawStop comes out with a hybrid, I will be buying it. I do not want the contractors saw or the cabinet saw.

I read some of the comments on that site. Someone said SawStop is selling 10-1 (in some markets) of all other sellers combined. can this be true?

[Rick Levine]

Wilbur Pan,

You have way too much time on your hands! LOL

[Wilbur Pan]

Wilbur

For sake of rhetoric....

What about the rate at which the blade drops away below the table once activated?

Also what resistance value are you assuming when cutting off a wrist? Bone is more resistant than flesh?

Also the spinning blade will try and push the wrist away and thus slow it down. Does the speed account for that?

As I mentioned before, the back of the napkin calculations I did assume that the blade is cutting away at full speed and efficiency during that 5 ms of contact, so all the factors that you mentioned would make the damage less than what my model assumes. If I was able to take those factors into account, that poor woodworker would have to be dropped onto a SawStop from higher than 39 feet to chop off his wrist. ;)


Wilbur Pan,

You have way too much time on your hands! LOL

Physics can be fun. ;)

Actually, this was in response to a post long ago here on SMC from someone who said that the hotdog demo didn't hold up because if you slammed your body into the blade on a SawStop at full speed, you could still cut off a limb. At the time, there was the perfect storm of me [1] reading that post, [2] being in a crabby mood, and [3] having a slow day at work. ;)

After I wrote this, the guy replied that by "limb" he meant "finger", which I thought was kind of weak.

[curtis rosche]

look closely the blade isnt damaged in the video. there is a peice of aluminum from the brake and there is a peice of plastic from the firing mechinism. nothing from the blade

[Cliff Rohrabacher]

a tad extreme but, hey~!! If he invented it he ought to have that kind of faith in it.

[Larry Frank]

I also cringed when I saw what they were doing. Yes, the Sawstop is a great piece of technology but I would NEVER put my finger in it as a test. I thought that the inventor was smart but this is anything but smart. Would I trade my Jet in for an equivalent Sawstop....Certainly. But until then, I will need to use my head and keep my fingers out of any saw!

[Don Abele]

...Would I trade my Jet in...

Larry...that's what I want. Let SawStop run a promotional sale...they take your old saw and credit you xx% towards the purchase price of a new SawStop. Of course, what do they do with all those saws???

I have a perfectly good Jet cabinet saw and can't justify the cost of a new SawStop (I know, safety should always be a justification).

A trade-up program would make the justification (and decision) easy.

Be well,

Doc

[John Coloccia]

FWIW...

I used to do semiconductor robots for a living. On one of our systems, we removed the "light curtains" (i.e. laser safety devices) and instead designed the system so that the torque/velocities achieved would not crush a hand if it were placed in the way of the robot.

The way I proved it to the customer is I stuck my hand in the robot as it got up to full speed. The customer thought I was a little nutty at first too, but the demonstration was quite effective.

If I'm the engineer, and I claim that it's safe, I'd better be damn well ready to stick my own hand in there. Period. If not, I have no business making the claims I make.

And yes, I own a saw stop, and no it has never just gone off accidentally, and no I don't care one bit that it trashes my blade to save my fingers, and I couldn't care less what anyone else thinks about my "needing" a gimmick because I'm an idiot who doesn't know how to use his table saw properly.

I think that about covers it.

[Dennis Thornton]

I read some of the comments on that site. Someone said SawStop is selling 10-1 (in some markets) of all other sellers combined. can this be true?

I wouldn't be surprised. If you were buying half dozen table saws for a high school what would you buy? Imagine trying to explain to a parent who's son just lost a few fingers that you saved $X buying another saw.

I can see where someone would go with another table for their own use, but in any larger shop I don't see why anyone would buy anything else. Heck, I imagine the insurance savings alone would make the Sawstop the cheapest saw to buy.

[Frank Trinkle]

Here's what I had to say about that video:

But there is a new video on You Tube in which a gentleman demonstrates the SawStop brake, not with a hot dog but with his own finger. When I saw this I cringed. The guy actually stuck his finger into a running saw blade. Am I the only one who is shocked by this? I hope not.

Confidence in your product is one thing but this is just plain foolish. It’s just asking for it. After all, this is an electro mechanical device and, sooner or later, somewhere, somehow, it’s going to fail to work properly. It would be tragic if that time just happened to be the time some guy who had seen this video was showing his friend how amazing his new super safe table saw was. Or to some guy who has been lifted to new levels of overconfidence by virtue of having seen this demonstration.

Personally, I would love to own a SawStop machine. And there is not much I wouldn’t give to have been working on one a few years back when it probably would have saved me from a serious injury. But I am amazed that they would publicly demonstrate this technology in such a manner. At least it should have a “don’t try this at home” caveat emblazoned across the screen in huge red letters."

The video you saw was the founder of SawStop proving the technology by using his own finger. You will also notice that he didn't RUN his finger into the blade.. he very very slowly moved his finger to the side of the blade and that's when the brake responded.

The concept is putting your "finger" where your mouth is... and that video along with the other information is exactly why I own a SawStop TS. (I'm a professional helicopter pilot, and if I lost a finger or two, I'd lose a 6-figure income on top of my finger... NO THANKS!)