Slashdot Mirror
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."
Something tells me the next one will be G rated.
Where were you when the voynix came?
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?
-- Josh
"Whoopie! Man, that may have been a small one for Neil, but that's a long one for me!" - Pete Conrad
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.
>> "What would the robut do? Frame someone!"
> 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.
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.....
liqbase
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?
Slashdot Burying Stories About Slashdot Media Owned
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...
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.
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...
If you think it's expensive to hire a professional to do the job, wait until you hire an amateur. --Red Adair
Finally, I can saw naked!
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.
Not a Twitter sockpuppet... but I wish I was.
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.
Cthulhu Saves.
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.
Get off my lawn.
Boy! Is my face red?!?
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.]
.. 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.
.. at $50+ a pop .. kinda hurts.
..
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
Destroying the blade of course. which
Another reason this hasn't been adopted yet is that pressure treated wood also tends to cause the brakes to fire off
--Ne auderis delere orbem rigidum meum, non erravi pernicose!
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 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/
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!
Eclectic beats from Leeds, UK
handmadehands.co.uk
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.
You can accomplish anything you set your mind to. The impossible just takes a little longer.
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.
r elpath=/pages/content/en_US/setonalerts/articles/0 904/0904_mach_safeguard.jsp
This is a good summary of the issues: http://www.seton.com/seton/internalHtmlAction.do?
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.
Since when did operating systems become a religion?
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.
"Ladies and gentlemen, my killbot features Lotus Notes and a machine gun. It is the finest available."
"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.
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 :-)
Open Source Alternatives
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.
science is a religion
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!
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.
There is nothing inherently safe about liberty. That's why so many people died protecting it.