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

Dupe from 30-Jun-04

[Anonymous Coward]

http://science.slashdot.org/article.pl?sid=04/06/3 0/131241

Which was probably duped again earlier.

Quick, go steal some +5 comments from that one!

"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?

Re:"Saw III"

[Orangejesus]

When he loses the hotdog and flips his dick out on the table I'll be impressed.

Re:"Saw III"

[Skreems]

I've actually seen a demonstration where the president of the company used his own hand. Quite a show of faith in your product, I have to say, and very impressive as a selling tool.

Re:"Saw III"

[Jim Hall]

I think he means "rated G, for 'Garbage'." :-)

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

[Rebuke]

Why wouldn't they want to embrace safety technology like this?

The most obvious reason is cost. If a company hasn't been hit by an accident in the past, then if (like a lot of companies) they're purely looking at their bottom line, why would they pay more for this saw than the one they've already got...

Re:Interesting Technology

[radarsat1]

Why wouldn't they want to embrace safety technology like this?

Same reason safety is an afterthought in many industries: expense. New technology is always a bit expensive. They need to make this cheap for it to be widely adopted. Otherwise it will only makes its way into the high-end equipment.

Hopefully they will be able to sell a critical mass quantity to bring the price down and make it available to every tool maker.

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

[sammy baby]

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

Then I'd say it's probably safe for you to pet my dog.

Otherwise, however, I'd be very, very careful.

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

[cluckshot]

Having 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.

Re:Interesting Technology

[plague3106]

Or, option three, outsouce the job completely to a country that wouldn't even consider using a safer saw.

Although I think your first two are options as well, you forget that not only do employers pay higher cost, if someone does get injured, they pay for the medical expenses related to the injury, likely for the life of the employee.

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

[AcidLacedPenguiN]

hotdog gloves?

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.

Re:Interesting Technology

[Hoi Polloi]

First seat belts then motorcycle helmets, what next!? Good thing the constitution protects my right to clean a gun with the barrel facing me.

Re:Interesting Technology

[cvd6262]

Yours are good points, but you can go too far.

When I was working at a storage systems facility owned by a large company, which it later sold to another large company, there was an on-site accident that landed an employee in the hospital.

Suddenly, we were policed for over-the-top compliance on every perceived OSHA requirement, greatly slowing down our productivity. For example, even though it wasn't policy, we were no longer allowed in the cleanroom without steel-toes shoes, etc.

Then we finally found out the details of the accident. It seems a portly man was in a cherry-picker, changing a light bulb in a warehouse. When he leaned over the controls to disconnect one end of the light bulb, his belly moved the lever and raised the platform on which we was standing. Of course, he was now squished between the ceiling and the control, and unable to turn off the lift.

Now, this was a serious accident, and resulted in pain and downtime for the employee in question. But his steel-toed boots didn't save him, so what was the point in making engineers where them in the cleanroom?

Getting back to the topic, I know there is a lot of accidents on construction sites. I have family members that have been seriously injured working construction, but most of those are from falls, not from saw-related incidents. So, would there be a better use of the time/money than on table-saw safety?

I also take issue with TFA:
"Here we had an unbiased government agency saying these saws are unreasonably dangerous," Gass says now. "So, yes, I did feel somewhat vindicated."

Anyone who's worked with the US government knows there is no such thing as "unbiased". The best you can do is balance the biases.

(Statistics from U.S. Consumer Product Safety Commission) A memorandum from the U.S. Consumer Product Safety Commission in June, 2006 states that "over a 10-15 year lifetime of a table saw, it would generate societal costs of $2,600 to $3,100" from blade contact injuries. Such saws typically have initial costs ranging from about $100 to $300.

Again, what about other safety issues? Is this the best use of regulatory funds?

(Bias aside, how much of the $2600 "societal costs" goes to funding studies to see how much they cost?)

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.

Re:Good product

[johnny cashed]

There was a large table saw comparison review in Fine Woodworking recently. His saw was one of the top rated. It is good that he has built an excellent saw (one that is excellent, even if it didn't have the safety features) that can compete with the best saws in the industry. His was also expensive, but I imagine that having fingers re-attached costs a lot more. The saw blade gets trashed when the safety fires, but again, a saw blade is cheap compared to a trip to the hospital.

As far as kickback, a saw with a splitter helps a lot to prevent it. I'm nervous around the table saw as well. I also like those with the sliding table, I believe that that also makes a table saw safer.

Re:Good product

[Anonymous Coward]

They have solved the kickback problem. First, this saw uses a riving knife at the back of the blade. That is, it has a rather sturdy curved blade that stays fixed behind the rotating blade. The riving knife goes up and down with the blade and helps keep the wood from touching the back of the spinning blade, which is the root cause of kickback. Another think you can already do to reduce kickback is to ensure that you fence is exactly parallel to the spinning blade. In the alternative, you can have the back of the fence a few thousandths of an inch further out from the blade than the front. This keeps the wood from getting pinched between the fence and the back of the spinning blade.

For those that are curious (I can't get the article to come up, perhaps the server is melting) the SawStop works by sensing a change in the electical resistance in the blade when it touches flesh. (Since wood is, generally, of low moisture content, it will not set off the mechanism.) When the flesh is sensed, a heavy spring launches a sacrificial aluminum block into the blade and another spring retracts the entire mechanism. The aluminum block and your $50 to $120 blade must be replaced.

-cliff

Re:Good product

[Fitch]

If you've ever been the victim of a kickback it's a good indication that you weren't using the tool in a safe manner.

Re:Good product

[jonored]

In all honesty, you need to be scared around it. Even if you have this system, you still need to be scared of the table saw. Just because the table saw is supposed to notice you and stop doesn't mean that it actually will; what if, say, some fleck of metal gets into the electronics, and shorts the mechanism holding that block back (haven't gotten to the article, but that's how I'd design such a thing - try to fail on the stop side), and when you trip into it moving too quickly it doesn't stop? While you shouldn't be scared silly by the machine, you should be scared to the point that you are always aware that being around this machine is inherently dangerous and always will be.

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.

Transfering the momentum

[suso]

Bret: "I only got a scratch from the blade, but I broke my foot when the whole table saw flipped over."

Whooops...

[Mad_Rain]

It looks like it couldn't stop the slashdot buzzsaw - it cut straight through their server.

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?

But what if I want to cut meat on my table saw?

[Anonymous Coward]

But what if I'm trying to cut meat on my table saw? I guess I'll be stuck with the band saw and the wood chipper...

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...

Re:This has been around for years

[jsupreston]

Not only that, but if for some reason the device acidentally trips, you're out a whole lot of cash replacing the blade, brake shoe and no telling what else. For someone who can afford a $2000 cabinet saw, this may not be that large of an expense, but for the average person doing this as a hobby, we tend to pinch every penny. Heck, I've been doing this as a hobby going on 10 years, and I can't justify to SWMBO why I need a dado stack for my saw. If I had to buy a new saw with this technology, I'd have to give it up, given the cost of the saw and repairs. Plus, a little common sense would almost reduce the need for this completely. Use a push stick when ripping narrow stock. Use feather boards where appropriate. Use a miter sled when cross cutting. If possible, leave the blade guard on (not easy...my previous saw was safer without the guard due to a crappy splitter on the guard). If you have to, paint a red line in front of the blade on the saw table showing where the blade is. Paint a perpendicular one showing where the throat plate starts. Don't stand in front of the blade if you don't have to. And, if you don't think it is safe to do the operation, then DON'T DO IT. And yes, before I am asked, I've not followed all the rules myself. I did get a very bad scare about 3 years ago. I was cross cutting something, and felt a really strange vibration on the tip of a finger. I looked, and somehow I had gotten the tip of a finger past the teeth on the blade, and my fingertip was resting on the side of the blade while spinning. Fortunately for me, I was not injured, and since then I have tried my best to make sure that I never have that situation again. I have found a great resource for all sorts of shop info, including safety. BT3Central.com has several forums. The forum was created for owners of the Ryobi BT3x00 saws, but anyone is welcome. I have gotten lots of advice and inspiration from there. We all pretty much agree that the idea behind the sawstop is a good idea, but not that practical given its cost. Like I mentioned earlier, most of us would have to give up our hobby if we had to buy one.

Re:Whats the problem?

[Rob T Firefly]

Good points, I can't begin to count the carpenters and hobbyists who have boneheadedly disabled safety features on things for the sake of speed, myself included.

This may have a brighter future in heavy industry and the assembly-line type of stuff, where the material going in is fairly standard and conductive things aren't normally involved, making more sense for the machine to crap itself when something finger-like does find its way in.

testing with hands

[raygundan]

As amazing as this thing is, and as remarkably fast as it stops the blade-- it's not going to eliminate injury. It will turn a finger loss into a nasty cut, though. And that, I suspect, is why the sales staff isn't karate-chopping the rotating blade during demos. The hotdog is always cut, just not cut in half.

Dunno about wet wood.

Yes!

[Geminii]

Finally, I can saw naked!

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.

Re:No big deal.

[microcars]

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

All they have to do is turn the key on the side of the unit that "disables" the safety feature.
It comes standard on the saw.

Some friends of mine own a Scene Shop that makes sets for Stage Productions and they bought a pair of these a couple of years ago.

Being a Scene Shop, they don't just use the saws to cut wood, they also cut Acrylic and Aluminum.

They HAVE to disable the safety feature to cut Acrylic and Aluminum or it triggers a False Positive and that quick cut ends up costing $150 to replace the blade and the soft aluminum block that slams into the blade to stop it so fast.

so far ALL the replacements have had to be done because the employee forgot to DISABLE the safety system when they were cutting something other than wood.

I wanted to give it too thumbs up...

[B11]

but alas the technology wasn't around in my 9th grade shop class.

Re:Link to web site

[Pontiac]

I forgot the link to the SawStop site
http://www.sawstop.com

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.

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

[jandersen]

I'd say, let the market sort this one out

This seems to be the new religion - at least in the US. 'The market' isn't some magical cure-all that is going to sort everything out and make the world a better place. Experience shows that free-market capitalism doesn't exist, among other things because every time restrictions are removed from businesses, we get monopolies, kartels and all the other diseases of extreme capitalism; thus, even if there are no restrictions imposed by the state, the free market will quickly be killed off by predatorial companies.

Instead of this pipe-dream about the holy and divine 'free market' there should be simple and clear restrictions in place that would favour the small to medium sized businesses; the bigger companies are simply extremely inefficient in a number of areas; in a small company each employee often has a big stake in the success of the company and will work harder and not waste resources. A big company will tend to extract money from society into some form af passive storage, possibly overseas, whereas in small companies the money tends to get spent in the local area to the benefit of everybody.

So let's put this silly, religious free-market mantra to one side; it won't benefit you or me (unless you happen to be a multibillionaire).

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.

Just call me Butterfingers!

[frogstar_robot]

Boy! Is my face red?!?

Re:Whats the problem? (Go here)

[Pontiac]

No Problem.. Get your $3,000 ready and go here
http://www.sawstop.com/

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 ..

Re:Whats the problem?

[jonored]

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". I'd be surprised if there were still many machines requiring manual work while running; they're less efficient and harder to make safe. And to boot, the two-switch system is much, much simpler and more robust. Much more likely to fail in the nonfunctional direction than fail in the squish someone sort of way.

Re:How does it work???

[jellomizer]

Well our bodies give off an electical charge (which is very close to a hotdog) and the blade being metal. So when it hits our skin a low level electic charge is shot across the blade into a chip that determins if it is the same electical change as a human hand. If it is then it fires a stopping pin that breaks the saw very fast, and allowing it to only scratch the finger, mind you it will be a deep scratch, and will hurt like hell but it will heal in time and with a banage you can continue with work that day.
As for the slasher movies, I am sure they can just take out the breaking pin, and they will be all set. Heck it allows for 1 more minute of the movie to expand it plot.

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:I tried to buy one.

[HiVizDiver]

We actually have one of those saws (Sawstop - I assume that's what we're talking about, the link times out for me) at work. It's $65 for the "cartridge" and the cost of the blade. So about $150 - $200. Seems cheap insurance compared to the $35,000 lawsuit some guy brought against us a few years ago for cutting his hand up in a regular 10" tablesaw, which was entirely his fault anyway. And it's a hell of a lot less than "a new tablesaw", which for a good one (not even a Sawstop brand) will cost you $1000 - $2000. Not trying to be a dick or anything, but they've come down a LOT in the last couple of years.

That said, personally, I'd rather take your suggestion of "it's dangerous, be careful". There are plenty of safety devices for tablesaws that work, most notably a pushstick and a bladeguard with a vacuum attachment. They jury's still out on splitters, though, I run into about 50/50 when I ask people their opinion on them. I can't say as I've ever used a saw that actually had one on it, though, so maybe that's saying something.

Re:I tried to buy one.

[Grishnakh]

They jury's still out on splitters, though, I run into about 50/50 when I ask people their opinion on them. I can't say as I've ever used a saw that actually had one on it, though, so maybe that's saying something.

That's because "splitters", as implemented on 99% of table saws sold in the US, are utter and total crap which should be banned. They don't work that well, they don't rise and fall with the blade, and worst of all, they're a pain to remove and re-install, in case you need to make a dado or other non-through cut.

The solution, of course, is the riving knife. This is required on table saws made in Europe. The riving knife is similar to the splitter, only it actually works well. It's mounted directly behind the blade, and is curved to match the blade's shape, so it's only 1/8" or so from the blade's rear side. It's also mounted to the blade height mechanism so it's always at the same place relative to the blade, regardless of the blade's height. And good ones are designed so that blade guards can be quickly and easily removed from the riving knife, in case you need to do a non-through cut. I believe the new Powermatic PM2000 saw has such a riving knife. Even better models have a dust collection port built-in.

As usual, stuff sold in the US is decades behind what people in the rest of the developed world have access to.

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.

Re:Who do you sue...

[mrjb]

Who do you sue? Sorry but that question is So American. The answer is: Who do you sue now, if you are foolish enough to let Junior operate a table saw *without* this safety feature and he cuts off his finger? Because you know it will come to that.

Re:NPR Covered This in 2004

[jandrese]

I thought the manufacturers were just relucatant to give 10% of the gross of every saw they sold to the guy who patented it. Basically, they liked the idea, but they'd have to increase the price of their saws by 5% or so to compete, and that's a lot of markup in a relatively competative marketplace.

Basically, it would have been like the guy who invented seatbelts requiring a licensing fee of $500 for each car they're installed in (back in the 50s).

Re:Whats the problem?

[johnny cashed]

In the US a safety that could be disabled by wedging cardboard in it wouldn't get past OSHA. They have thought of that and require the buttons to cycle, so you cannot just wedge it. I believe that in Europe, light curtains are also used. They are used in the US too, but not by themselves, because OSHA has very high standards for a light curtain system.

This is a good summary of the issues: http://www.seton.com/seton/internalHtmlAction.do?r elpath=/pages/content/en_US/setonalerts/articles/0 904/0904_mach_safeguard.jsp

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.

Need a "good samaritan" exemption

[Kadin2048]

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.

An well-said, although unfortunate, point.

It's seemed to me for a while that we need -- if we can't actually accomplish all-over tort reform -- some sort of a "good samaritan" law for corporations as well as individuals.

There shouldn't be any liability reasons for not putting a safety device like this on your equipment. But the system as it stands doesn't encourage it, for exactly the reasons you mention. Without a safety device, and as long as they're not "expected," when someone takes their finger off, it's just their own damn fault. But with the safety device, they'll be a massive lawsuit whenever it doesn't work perfectly -- even though it might work very well most of the time.

This reminds me of the situation in many states prior to the introduction of "good samaritan" liability laws. You'd have doctors and off-duty paramedics driving past the scene of an accident and not stopping, because nobody wanted to risk getting sued. It was only after some pretty ridiculous and unfortunate situations, where it became clear that as a society, we shouldn't be encouraging people to leave their fellows bleeding to death in a ditch because of fear of being sued later, that many states have changed the law.

A company which makes it's products safer than the norm shouldn't be liable for suits when the safety mechanism fails, if the result of the failure is that the product is only as dangerous as the device would normally be expected to be (assuming the manufacturer has not advertised it as being much safer, or that less precautions are necessary).

Any time you have the law encouraging the creation of more-dangerous products for perceived liability reasons, you have a problem. The goal of the law should be to encourage and reward productive behavior, not discourage and punish it.

Re:Need a "good samaritan" exemption

[soft_guy]

Great. We will have companies that make cheap "safety" equipment that doesn't work but meets the legal requirement so that they can't be sued. Sounds like a republican dream. Whoopie!

Re:Need a "good samaritan" exemption

[a_nonamiss]

It reminds me of the last time I went golfing. Most nerds will realize that metal golf clubs, open spaces and lightning is a really bad combination. Because of this, golf courses are required (at least in my state) to be outfitted with a blaring horn that is supposed to sound when anyone spots lightning. Well, last time I went golfing, we saw lightning off in the distance and ran for the clubhouse. We told them they should sound the horn because a big storm was coming and we saw lightning. His response floored me.

"If we sound the horn, we are legally responsible for making sure everyone gets off ths course. On the other hand, if we "don't see" the lightning and don't sound the horn, we aren't liable, because it's an unforseen act of God. Therefore, we never sound the horn."

So we live in a world where it is advantageous for the owners of a business to turn a blind eye to potentially fatal weather conditions because some idiot somewhere sued the golf course after the horn sounded and he stayed out anyways. There are probably hundreds of people across the country who have been seriously injured or killed by this easily preventable problem, and probably a half-dozen responsible for getting it enacted in the first place.

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.

Butcher Re:Whats the problem?

[Forge]

I don't know where the rest of Slashdot buys meat but most of my Butchers use table saws or belt saws to slice meat.
Lets add a tempreture sensor so it knows cold, dead meat from the live kind your hand is made of.
To clarify

Re:Butcher Re:Whats the problem?

[X0563511]

Unfortunately (speaking as a former meat-clerk) your hands soon become quite cold, as you cannot wear gloves for safety reasons (better to loose a finger than have your mesh glove get caught on the saw and throw you into it, or simply rip your hand off/apart)

Re:Whats the problem? (Go here)

[Sebastopol]

This is a fantastic saw. I don't know about the skin-detection feature, but it is the first american saw with a riving knife (before PowerMatic), and it has a European style shrowd covering the entire blade. Not to mention the beefy trunion. Even without the safety feature it is a great saw. Now if we could start getting some sliding top saws like they have in Europe...

"Do you expect me to talk?"

[hoggoth]

"Do you expect me to talk?"

"No, Mr. Bond, I expect you to get a 1mm cut and ruin my blade..."

Re:Whats the problem? (Go here)

[bsane]

Exactly... The riving knife is at least as important to saw safty as the stopping feature. The absolute worst table saw accidents come from kickback, not fingers touching the blade.

Riving knives protect from most types of kick-back, and yet the saw-stop is one of the few US saws to have them.

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: cutting frozen meat

[maddogsparky]

My dad once butchered an animal (beef, I think) and left in the barn to cool. He couldn't get to it for a few days and it froze solid (Minnesota winter). He needed to cut it into smaller chunks to be able to carry it inside for cutting up. So he thinks: chainsaw!

Much of it had to be thrown out due to all the bone chips. :-(

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!

Re:Whats the problem?

[rs79]

"better make sure the wood you are sawing isn't damp"

An interesting guess but wet wood (which you REALLY shouln'd be curtting) isn't going to have the same electrical properties as wet salty flesh which is MUCH more conductive.

Mmmmm... wet salty flesh...

Macho Men

[Detritus]

I'm disappointed to see all the posts from the "macho men" on slashdot, who think safety is for wimps, and if you saw your hand off, you're stupid and it's your fault.

I hope that every time a worker loses fingers to a traditional table saw, their employer gets hit with a big lawsuit. Endangering yourself in your home workshop is your choice, but you shouldn't be able to impose that decision on your employees. I have an Uncle who was almost killed by a poorly maintained saw at his workplace. He lost part of one hand. It was pure luck that it didn't cut him in half.

You can't assume that the equipment is in good working condition, and that the operators are properly trained and alert. You have to take active steps to regularly inspect the equipment for problems, perform preventive maintenance, train the operators on how to safely operate it, and make sure that everyone is actually following the safety rules. Any machine that relies solely on operator alertness to prevent an accident is an accident waiting to happen. Real people get distracted and have off days.

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.

Power tool injuries

[gone.fishing]

It can happen so quickly and easily that when it happens you don't even know that it has happened. The cut doesn't hurt as badly as you would imagine, in my case it felt like I was touched with a feather. It was just a very light brushing sensation although my mind knew immediately what had happened.

I was very lucky, I did not cut any bone and I only lost a strip of tissue about an inch long, maybe 3/8's of an inch deep and 3/32's of an inch wide out of my thumb. Still it was a sobering experience that left a piece of expensive oak ruined (not to mention the blood rushing out of my thumb). What happened is that I was making numerous identical cuts and I got a bit bored and for just a moment I didn't think.

I try not to be stupid around power tools; I am not a professional, just a hobbyist and am very aware of my relationship to my tools. While I have learned to trust them, I have also learned to distrust them and always try to be as safe as possible. I think that the table saw is probably one of the more dangerous tools in the typical wood shop simply because there are so many times when you have to work with this guard removed or you are tempted to make a fine adjustment with the power on.

I am frankly a bit offended by the industries lack of enthusiasm for this kind of product (although on the flip side, I also understand that it would make every new saw much more expensive). The power tool industry is very aware that their products can cause serious injury (up to and including the loss of life). When they have an opportunity to make their products cheaper, they are morally obliged to do so. While this high-tech solution my have some shortfalls, it is obviously a step in the right direction. I suspect that the industry can find ways of making similar safety devices that work in different ways if they want to or are "encouraged" to. .

This isn't new...

[SFEley]

These things have been available in industry for a few years now. My wife works as a chemist for a major wood products company. They got this table saw last year.

The replacement parts expense isn't nearly as bad as it's been made out to be, either. They accidentally triggered the 'quick stop' feature the other day -- not with a finger, but sawing some wood that was too wet and therefore coincidentally had the right electrical properties. Replacing the blade turned out to be about sixty bucks.