Skin Sensing Table Saw

killabrew writes "Check out this article from Design News about a new skin sensing table saw technology that is on the verge of becoming a mandatory piece of hardware on every table saw. For years inventor Stephen Gass persevered in the face of legal, corporate and technical foes, he is forcing society to rethink its acceptance of saw blade accidents."

Comments

"Saw III"

[krell]

Something tells me the next one will be G rated.

Re:"Saw III"

[ahem]

Is that "G rated" as in "rated G by the MPAA", or "grated" as in shredded up?

Interesting Technology

[Kranfer]

At first I was very wary of reading the article, thinking how could it possibly sense that? Then I watched the video... very very nifty it barely cut into the hotdog they used as a test. Now, I would think this technology would be VERY welcome in all industries where moving parts like saw blades, robotics etc are used... Why wouldn't they want to embrace safety technology like this?

Re:Interesting Technology

[metasecure]

didn't RTFA, but what if your skin is not made of hotdog ?

Re:Interesting Technology

[M-G]

Because safety technology sounds good, but frequently doesn't hold up to heavy use, rough handling, dirt, etc. on the job site. Then the safety device gets in the way of getting work done, and it gets bypassed. And for all of that, you get to pay more for the tool.

Re:Interesting Technology

[TykeClone]

Perhaps hotdogs are made of fingers?

Re:Interesting Technology

[UbuntuDupe]

That's true, but it's not nearly as malicious as you make it sound. Employers have choices: they can pay to eliminate the hazard, and then have to pay less to get workers to take the less risky job, or they can not eliminate the hazard, and have to pay more to get people to take the more risky job. Economists call this a "compensating differential". It's seen in the difference in pay between regular window washers and high-rise window washers, for example. It can also be negative in jobs that people enjoy doing (i.e., they make less than those of comparable skill and experience because the job is fun, like astronauts).

There is always going to be some level of safety below which people will say, "forget it, it's not worth it, I'd rather just take the cash than make myself 1 in a million less likely to die". For example, would you take a 20% pay cut to halve your risk of death on the job?

Re:Interesting Technology

[shawn(at)fsu]

Then the safety device gets in the way of getting work done, and it gets bypassed
or it gets by passed because people are lazy and management looks the other way. For example the meat slicer at a restaurant/deli. I heard horror stories from my friends that started part time jobs in HS before me about how dangerous the slicer was they'd show me the cuts and the missing tips of fingers that would end up in tonight's bread pudding. So when I got a job that required me to use the meat slicer I was very careful and I found that if you would just keep your hand on the grip and behind the "shield" you were ok. I never cut myself or came close to it. So my point is even if the safety device is simple and it doesn't get in the way of proper use people will still find ways to hurt themselves in efforts to expedite their tasks.

Re:Interesting Technology

[Junta]

It's people. Hot dog is made out of people. They're making our food out of people. Next thing they'll be breeding us like cattle for food. You've gotta tell them. You've gotta tell them!

Re:Interesting Technology

[Registered Coward v2]

aving worked as RN in a large factory which had Lost Time Injuries approximately every 3 days.... and which could have saved a fortune if modest changes had been made, I have discussed this with management.

The motivation of the management who makes the decisions is one of control and temper. It really does make sense to make things safer. This factory could have saved about $100,000 a week had it improved safety. They just didn't want to do it. You see a worker was only paid about $50,000 a year and as such these people didn't cost management enough to be worth anything to them.

I watched the expensive management employees get protected while the workers got nothing. This was a tire factory. They made $1,350,000 a day even with this injury expense. It may be strange to some but actually the workers were too cheap to be worth anything. The loss of a life about every year or so was an acceptable cost to management. So what if you pay off the family with a damage claim of $500,000 or so. Blow it off. These people are worthless in the eyes of management...

Saving $5,200,000 a year simply didn't enter their mind as worth that much effort. I proposed that we use the medical data to extract which machines should be fixed. I offered to observe the machines and look at what was going on. They had no interest. One major loss to them was hearing losses. The addition of a few minor changes could have nearly silenced the factory. They couldn't care less. Another major loss was loss of hands and fingers and intermittently a person in a machine. Simple design changes in jobs would have improved production and saved lifes. They didn't care because it might "bother" their situation. It was an attitude that the "Free Trade" advocates refuse to recognize. Burried in the true motivations of many rich persons is a hatred of other social classes and a view that they are property not people. This is why they will not embrace safety technology.

Your numbers don't make sense - $100,00 is about 1% of a weeks take (per your numbers) which is usually enough to get a company take notice; which is why I doubt your numbers. Either they are wrong or the required changes were so expensive as to be unaffordable - so when you say:

One major loss to them was hearing losses. The addition of a few minor changes could have nearly silenced the factory.

I have to wonder - silencing an industrial environment is not easy nor cheap - which is why wearing proper hearing protection is generally the best fix (and enforceable as well).

Then again, your last paragraph shows where you are coming from - I sense you had an agenda that was not well received and probably not realistic nor practical.

Re:Interesting Technology

[twistedsymphony]

You're damn right... who says I have to use the saw to cut wood.. what if I'm cutting up say.. dead bodies? I think they'll be cutting off a whole demographic of people who might otherwise buy their products. Maybe they'll have a switch to go between "wood" mode and "dead body" mode or something. I guess they just don't make 'em like they use to.

Good product

[dave-tx]

Here is a writeup of the saw's debut at the International Woodworking Machinery & Furniture Supply Fair (2000). I remember reading this back in 2000 thinking "great idea, but I wonder if it'll ever get adopted". Glad to see it's gaining traction - the table saw is the only piece of equipment in my shop that I'm nervous around.

Now if they can solve kick-back, I'll be a tablesaw fiend.

Oh, the humanity!

[Anonymous Coward]

> For years inventor Stephen Gass persevered in the face of legal,
> corporate and technical foes, he is forcing society to rethink
> its acceptance of saw blade accidents."

Proof of why this technology is needed: the above sentence was horribly, tragically mangled in a comma splicing accident.

Re:Whats the problem?

[LiquidCoooled]

There are benefits and there are drawbacks to this method.

It works really well for none conductive materials (uses skin capacitance to make a circuit, then when made retracts the blade), however if your cutting up things which trigger it randomly you will disable the feature (yes its not all the time).

Each time it is triggered the blade is ruined and needs replacing, better make sure the wood you are sawing isn't damp or you will either remove the safety feature (to save money) or get pissed off because you have to spend 10 minutes to change the blade every few planks.

It would be better to concentrate whilst working than making silly mistakes every day, may be good to replace machines with this and for those silly enough to trigger it more than once disable the feature and let them learn a valuable lesson.....

End of an era.

[Rob T Firefly]

Gone are the days of charming high school wood-shop teachers who hold up two hands' worth of fingers when counting off their five years' teaching experience. What's next, forcing them to shave their woodsman's beards and stop wearing flannel?

always two sides to every story

[Anonymous Coward]

As someone who was involved in evaluating this technology for a major US manufacturer of power tools, there are a number of issues which prevented early adoption. First and foremost was the inventor's demands for unreasonable royalties (including a percentage of the gross sales of table saws from preceding years!). I heard the director of the power tools group say that if the royalty had been reduced by 50%, it would have been a no-brainer. As it was, the proposed royalty structure was just unsupportable for a saw that sold for $500.

The second issue was that the product had great difficulty distinguishing the change in capacitance due to human flesh from that due to very wet lumber. This has undoubtedly been improved over the past few years, but people would have been somewhat unhappy to have false triggers that required them to a) replace the safety cartridge and b) their saw blade, which is consumed when the system triggers. Not to mention having the bejeesus scared out them when the system fires in error.

To talk about the inventor persevering in the face of corporate pressure is silly. This isn't a David vs. Goliath story. The inventor was a patent attorney that tried to bludgeon power tool companies with a 250+ page patent, and he could have sold his concept on day one if he hadn't been quite as greedy. There was no shortage of companies looking for competitive advantage in the power tool industry, which has been pretty stagnant of late.

Re:always two sides to every story

[radtea]

This isn't a David vs. Goliath story.

Yeah, this is more of a Beavis vs Butthead story, and is fairly typical of the way new technology is introduced.

Part 1: Clever, arrogant guy gets brilliant idea and develops it to the point where he is convinced it'll change the world. That's the science and tech part. Now it's all done, ok? There is no more science or technology in this story after this point. Only politics and monkey psychology.

Part 2: Clever, arrogant guy tries to change the course of history in a year or so, and cash in hugely in the process, by selling his idea or some instantiation thereof to established industry players. He pisses off everyone in the industry in the processes, which is easy to do because they are at least as arrogant and far less clever than he is.

Part 3: A messy, improbably stupid battle of wills ensues as the industry tries to do an end-run around the inventor and the inventor tries to harrass the industry in to buying his tech. This can go on for as long as decades, but if anyone "gave in" it would be a matter of "losing face", and "face" is extremely important to monkeys. If a monkey loses face, he will be demoted in the hierarchy of the troop, and that has all kinds of costs associated with it, including potential mating opportunities. So evolution has pretty much tuned monkeys up to act like arrogant assholes in these situations, because arrogant assholes are what female monkeys are most interested in, because arrogant assholes can command a greater fraction of the troop's resources.

Epilogue: Many years later, the technology is widely adopted and all concerned are hailed for their forward-looking stance and innovative thinking. Companies that fought the tech tooth and nail now tout themselves as early adopters (which they may well be, relative to other companies.) The original inventor, ignoring all the progress that has been made in making his original prototype a practical, manufacturable device, is hailed as a great innovator.

The amazing thing about modern social democratic market societies is that we are actually the most efficient innovators in history, and not by a small fraction.

This has been around for years

[Pontiac]

This guy has been trying to force his invertion on us for years..

After the saw manufactures refused to pay his unreasonable licensing free (3-8% of the saw sale price)for his patented tchnology he moved on to lobbying for a law to make it mandetory (and still pay his licensing fee)

I have to agree the idea is cool but I don't like having it forced down my throat.
He did go on to start his own saw company and makes one of the best saws on the market...

No big deal.

[WhatAmIDoingHere]

Professional carpenters will just find a way of disabling this, like the blade guards on circular saws and the 'safety' on nailguns.

Honestly, you're not a carpenter unless you have a few battle scars to show off.

I've got no problem with this except...

[awing0]

The fact that this may be mandatory bothers me. It's like seatbelt laws, lawnmowers that stop running when you get off the seat, and coffee cups with warnings. I'd say, let the market sort this one out. Yes it's cruel, but feel free to give me a Nelson "ha ha" when I run my hand through a chop saw.

Table Saw Safety

[clintp]

I *have* had a finger get chewed through by a table saw.

I was cutting a piece of wood that was way too small for a table saw to cut safely and it got my index finger. An avulsion laceration about 1/8" wide, right across the fleshy pad of the finger, down but not quite to the bone.

My fault, I know. I didn't sue anyone, and wouldn't have thought to even if it took my hand. [For a cut that small and precise, I should have walked out to the workshop and used a band saw or built a jig. But I was lazy...]

This is a great idea, but like another poster said it has to be cheap, and it has to be non-obtrusive. The safety of the device is a trade off against its utility. If the saw stops working because of a faulty safety switch, the safety switch will get removed. If it's expensive to replace, it will probably not be replaced.

For example, my table saw has a kick-guard that goes over and behind the blade. It's an incredible pain in the ass because gets in the way, it's hard to see around, and makes some cuts damned-near impossible. It was removed.

Make it cheap and make it reliable, and then it'll actually save some fingers.

This has been around for years

[RembrandtX]

Its been around for years, and has been shopped to the major power tool manufacturs [one of the largest, I used to work for, so i'm not talking out of my butt here.]

All of them turned it down due to legal implications, as well as adding to the cost per unit price.

Leagally, if a power tool manufacturer added this to their existing line of table saws, it *COULD* be taken as an admission of guilt that their previous models were not safe, any accident cases (no matter how stupid) would then have another chance at a successful suit.

Also, the inventor has been lobbying for *YEARS* to get his invention as a required component of table saws. He hasn't even had success in California - the most liberal state for passing stuff like this - let alone elsewhere.

I'm not knocking his invention, I've seen it pitched first hand .. the guy whipped a raw hot dog at the blade as fast as he could, and there was only maybe 1-2mm of damage to the hotdog before the blade dropped down into the brakes.

Destroying the blade of course. which .. at $50+ a pop .. kinda hurts.

Another reason this hasn't been adopted yet is that pressure treated wood also tends to cause the brakes to fire off ..

This has been out for *years*.

[Chirs]

For the non-woodworkers in the audience, this tech has been available for several years, and information on it was available for at least a year before the saw itself.

The "Sawstop" modifies the electrical potential of the blade, and can thus detect when skin hits the blade. Of course it also triggers if you cut metal, so it has a disable switch. Apparently wet wood doesn't trigger it.

When it detects flesh, it has an explosive charge that rams a chunk of aluminum into the blade stopping it within ~3ms. I saw it demoed in person at a wood show. The demonstrator slid a hot dog into the blade at a fair speed and there was a large bang. The hot dog had been cut into maybe 1/32" or so (a bit under a millimetre).

The main problem is that the inventor wanted huge royalties from existing tool companies, and tried to force through legislation making it mandatory to include the device on *all* table saws in the US. As you can imagine, people were less than impressed about having it rammed down their throats. Even now, the saw that incorporates this is a very nice saw, but they still charge about 30% more than for other comparable saws.

I tried to buy one.

[RonTheHurler]

I saw this demonstrated once, on the Tonight show, with Johnny Carson (yes, I'm that old and yes, this thing's been around that long!)

So, when I finally had a reason to go buy a tablesaw for my business, and I saw the horrible cost of insurance, I tried to buy the auto-shut-off table saw. Of course, I searched the web. Then I called the big saw distribution importers and distributors. It took some effort, but I finally got an answer why they were not, and probably would never be available.

It's not a perfect product. It is still possible to get your fingers cut off, and it is possible to have it "jam" on plain old wood too. When it jams, you have to replace the blade and the whole blade jamming mechanism- it can take most of a day to do that, if you have the parts, and it's expensive. It can cost as much as a whole new table saw each time it goes off.

All those things are solveable, but I was also told that the insurance companies hate the thing. It sounds counter-intuitive, but you know that a table saw is dangerous. If you believe that it's less dangerous, then you might be more careless too. The car companies had a similar argument against seat belts back in the 1960s.

There are better solutions in industry. CNC automated machines are used where lots of similar parts need to be made. There are very few, if any, one-off parts in manufacturing environments. So the only real market for this machine is the hobbyist or general contractor and cabinet maker, and the professionals have really good stafety rules anyway (at least the ones where I worked did).

But, as it stands, nobody has a case if he tries to sue the manufacturer because he cut off his finger. But put an auto-brake on the saw, and every time it fails the manufacturer and insurance company have a dismemberment case to settle.

-------------------

Use your table saw today! Get catapult and trebuchet kit plans at http://www.trebuchetplans.com/

Re:Whats the problem?

[AGMW]

In heavy industry you are more likely to see a safety feature like "both of your hands must be in the boxes and you must press both buttons to activate the machine that'd make you into paste".

A mate told me about such a machine - ie must be pressing two buttons before the machine will operate so you MUST have your hands clear - but some bozo figured out you could save a bunch of time by wedging in one of the buttons with cardboard so you only have to press one button.

However much we try to make things idiot proof, nature can always counter with a better idiot!

Bad memories

[JediTrainer]

Sigh. That reminds me of the time that my dad and uncle came up with the brilliant idea of cutting frozen salmon on our table saw.

In the basement.

The finished basement.

After all was said and done, walls and ceiling were covered in fine salmon shavings. Gross. Mom was less than thrilled.

Not so great

[MatD]

I've been reading about this (and talking to thel company about it long before it ever got produced). This is a good invention, but I wouldn't buy one. Here's why.

You can't cut green wood (wood that hasn't sat around long enough to get down to 10% water). I've gotten construction grade lumber that would easily have tripped this.

Most accidents on the TS aren't from people accidentally putting their hand in the path of the blade, it's from them either slipping (in which case they are essentially slapping the blade, and will still get a very serious cut), or from kickback. I believe (though I don't have a source) that most accidents are from kickback.

Also, many people take the blade guard that is included with their saw off becuase they think it gets in the way (which I've never really understood). If you were to look at the number of accidents on the TS, I would be willing to bet that most accidents involve a TS without a blade guard.

Most damning though, is that when this unit does go off, your saw blade (that you pay $100 a pop for) is rotated down into a block of aluminum, and gets welded there from the heat. Even if you can extracate the blade from that block, it wouldn't be safe to use it again, so you have to buy a new blade, and a new cartridge.

Table saws have been around for at least 100 years in their various forms and most woodworkers can still count to 10.

Re:Whats the problem?

[TheLink]

"It would be better to concentrate whilst working than making silly mistakes every day"

Why don't you drive without a seatbelt, and with a sharp metal spike sticking out from your steering wheel instead of an airbag? That'll definitely help your concentration won't it?

People make mistakes all the time. And sometimes it's you who suffers for someone else's mistake.

As for learning lessons, people still get cut by this saw - just look at the testimonials on their site. Wouldn't it be better that people learn their lessons from a painful nick and the cost of fixing the saw than losing an entire finger (or more)?

The problem I see is lobbying for a law that requires people to license patented technology AND making the license fee expensive. Of course if I hear wrong and it's a reasonable fee, then the saw industry people are the greedy selfish ones.

work safetly

[elmartinos]

If you care about safety, you absolutely have to see this great lift truck safety video. Unfortunately it is in German, but you will definitely get an idea why safety regulations are so important :-)

Re:Who do you sue...

[pclminion]

And if it is so great and reliable, why are they using hot dogs and not this guys hand?

That's a little like asking why they don't use live people instead of dummies in automobile crash tests. Don't they have any faith in their products?

Anybody with a realistic sense of safety and security understands that even if your safety system is 99.9% reliable, you still don't press it into service UNLESS ABSOLUTELY NECESSARY. Why have a 99.9% chance of being okay when you can have a 100% chance of being okay? When using a table saw, your PRIMARY line of safety is not putting your fingers in the fricking saw, NOT some fancy electronic capacitance gizmo. It's great to have that around in case you decide to be an idiot one day, but relying totally on it as an excuse to be a dumbshit is stupid, and if you lose a finger you get what you deserve.

In rock climbing, great pains are taken to make sure the climbers have SOLID ANCHORS to the rock face -- attachments that you could hang a Chevy from. That still doesn't mean you're going to deliberately fall on your protection!

Safety aside.....

[Sergeant Beavis]

Its actually a pretty damn good saw. I've used the SawStop cabinet saw at a couple of demos and I've been impressed with it. Losing a digit is always a concern, but anyone with a healthy respect for their tools will come away with fingers intact. Kickback is a much more dangerous situation because it can happen even when you are being careful. The SawStop has a self adjusting Riving Knife that prevents wood from binding against the rear of the blade and thus being thrown back at the end user. I've been into woodworking since I was 5. I've gone to many church and house rasing to help others and still volunteer my skills to Habitat for Humanity. In that time, I've been fortunate to keep my digits, but I've experienced the pain of kickback once. I was lucky to have gotten away with just a bruise. Kickback can flat out kill a person. Riving knives are very common on European built table saws, but are rare in the American market. We usually get a splitter with kick back cawls that should catch the wood as it gets kicked back. Normally it works well but a Riving knife prevents kickback in the first place. I can't think of one other US manufacturer that offers it on a cabinet or contractor saw. Saw Stop includes it on all of their saws.

Outside of those items, the SawStop is also very well balanced, it has almost no vibration, even less that most other Cabinet Saws. The trunions are solid and move the blade into position with little effort from the user. It also has a magnetic cutoff switch positioned right above the users knee for quick shutdown. It also includes a Biesemeyer style fence. Its only real drawback is that it is very expensive at $2800 for the basic saw. Options can run well over $5000. While I still like it, that money could be better spent on a European Combination Machine such as the Laguna or a Delta Unisaw with alot of money left over for other tools.