New technology makes it impossible to cut off a finger. YouTube (MetaCafe actually…) video:
http://www.metacafe.com/watch/774738/safetsaw/
Really amazing how it cuts the plywood until the hotdog stops it dead.
I saw this a while back - it’s a great idea, but the trouble is that when the device is triggered, it trashes the blade and (I think) needs to be reset by the manufacturer. That’s great for your finger, but not so great for productivity if the thing that set it off wasn’t a finger, but a bug, or a drop of sweat on the wood, or something else like that.
The brake cartridge is user replaceable - you’re out $60 or so for the brake and anywhere from $50-$120 for the saw blade. Compare this to the cost of downtime, trip to the ER, etc. for even a “slight” tablesaw accident and you’ll come out far ahead monetarily.
The Sawstop folks claim that the system will not be triggered by wet wood; it triggers based on the change in capacitance detected when the blade hits the human body. Obviously a hot dog trips it, I dunno if something as small as a bug would but what are the odds of that happening anyhow?
All the reviews I’ve read of their cabinet saw have been quite positive. If I’d had the money a few years ago I’d have bought a Sawstop instead of my Unisaw.
I seem to recall it costs about USD250 each time. However, it is fitted with a “test” mode so that you can offer up the wood, see if a light comes on indicating that it would trip, and if not start the saw. I saw a report from a large cabinet making concern that had been using the saws for a few years and had worked out that what it saved them in lost production and medical bills etc was at least one and maybe two orders of magnitude greater than what it cost them in false alarms.
It does trash the blade, but you don’t have to send it to the manufacturer for a reset, the manufaturer says swapping out the cartridge can be done as quickly as changing sawblades. Replacement blade safety cartridges cost less than $100, plus a new blade would be needed.
The website for the company making these is Sawstop . I saw this a while back, and recently saw it featured on This Old House.
According to the website, the trigger mechanism can be disabled for use with wood with high moisture content. I have no idea what would happen if a fly landed on the blade, but I wish my Dad had had one. He stuck his fingers in his tablesaw at least twice, and while he didn’t amputate them either time, he suffered some serious hurt.
I recall reading something about the Sawstop folks going before OSHA, and there is a possiblity that this sort of tech is going to be required at workplaces using tablesaws in the future.
oh yeah, previous thread…
Surely it must be possible to design a system that does something like this, but doesn’t stop destructively, requiring such an expensive reset?
And besides, how am I going to cut my hotdogs now?
And why do saw blades come in packs of 10 while hot dogs come in packs of 8?
Because the type of person who cuts their hot dogs on a saw bench gets their finger instead 1 in 5.
I also heard about this a while back on NPR. I remember them saying that all the big tool companies didn’t want to come near this technology because they make tools, not safety devices, and because it opens them up to liability. For example, if they did incorporate that technology, what if someone got hurt anyways or was using a lesser model? The latter could imply that the manufacturer chose to not put that feature on that model.
I sure wish my BIL had this safety feature on his saw a couple of years ago. He amputated his thumb and two fingers with damage to one other finger. He was working outside, wearing gloves. The glove got caught in the saw and pulled his hand in. He saw it happening, turned the saw off when his glove got caught, but the blade was still spinning even with the motor turned off.
He was lucky (?) in that there was a specialist at the hospital when he arrived, so they did reattach every thing. Had it been any other doctor, they would have just stitched the wounds closed and that would have been that. He was in surgery for 10 hours. He had a close call with the anasthesia and nearly died.
It took a long time to find his thumb in the bushes, his adult son and his son’s girlfriend found it, but the docs cleaned it up and stuck it back on. His amputated fingers were still in his glove, so they were more easily found.
He sent me a picture of his thumb after the doc had cleaned it up. I mean just his thumb, all by itself on a little piece of gauze. It was really quite shocking to see that photo and know that this lonely little thumb belonged on his body.
After surgery, his hand looked like it was formed from hamburger meat. I thought the doctor had wasted his time doing it and put the BIL through extra pain for no good result. All his fingers did stay attached though, and cosmetically it does look like a hand with fingers.
So, he has no knuckle in his thumb, the saw destroyed that, which means his thumb can no longer bend. He’s missing a knuckle in his ring finger too. Even though they put all the pieces back on the right places, his thumb looks really small, like they attached a finger on there instead of a thumb. He says that is because the fat pad in his thumb died. His fingers and thumb are there, but they’re not much use really. He lives in Canada, and finds the cold really affects his hand now. If his hand gets chilled, he’s in pain for hours at minimum. Even just being outside for too long can do it, much less getting out there to shovel snow.
It would be nice if they could design a brake that didn’t cost so much each time it’s tripped, but I suspect my BIL would consider the price of the replacement parts for the saw to be a bargain.
I think the costs would gladly be paid out by any company or person that would have been cut by a table saw.
This happened at the local Pizza Hut during a remodel. The thumb was finally found later that day on a window sill. I guess if the windows had been out a motorist might have had a surprise when the thumb hit their windshield. The guy, his wife, and his son apparently cut off fingers all the time. The son has only done it once, unlike ma and pa. My two brothers witnessed this, and the guy told them all the instances in which the family lost digits.
I still don’t know it would be effective. I can see that you’d think it was well worth the money if it was actually your fingers that set it off, but if you had to shell out for a new cartridge after cutting damp wood, you’d think quite the opposite - and you’d probably just get in the careless habit of pressing the override every time, so you don’t have to fork out more cash for another false positive.
Carelessness will find a way to get itself injured, no matter what. And careful people just don’t need it. It’s not even like a seat belt or a crash helmet, which protect you from being at the mercy of other people’s stupidity.
That blade’s going pretty darn fast, even putting your finger through one full revolution wouldn’t be pretty. Sure, you could use a disc brake type device, but it’d take longer to stop the blade, letting it cut through the finger while it slowed down.
If the wood were as damp as a hot dog, you’d be able to tell before even cutting it. I worked in a carpenter shop for a couple years, and we never had to cut wood that damp.
I’d be curious to know how this new saw would work in the scenario jeepus describes. Obviously, (I hope) once the saw got through the leather glove and hit skin, the capacitance change would trigger the brake, but is there anything in the changed scenario that would make working with gloves less safe?
Even careful people can make a careless mistake. You can’t buy a replacement knuckle. You get to make your own decision of course.
Tomndebb, I would expect that as soon as the blade touched the skin, the brake would be triggered, which would be too fast for the glove to get tangled with the blade. I’m really impressed at how quickly that blade disappeared once it touched the hot dog in the video. My son, who is 16, is working with a table saw at school this year. He’s not known for being careful. This, combined with my BILs accident, has me thinking about table saw safety a lot right now.
Gloves often make you less safe for a variety of reasons.
First is the “I’m wearing gloves!” mindset of a false sense of security. A misplaced sense of invincibility is dangerous.
Second is reduced dexterity - unless you’re wearing surgical gloves, you may as well be wearing oven mitts for how poorly most gloves fit.
Another issue is you don’t know exactly where the fingertips are - loose gloves have a nasty way of getting snagged on moving parts and dragging your hand in.
You’re working with machinery that will effortlessly go through thick chunks of wood. Steel and carbide will always win over canvas or leather.
Like my dad - he lost the tip of his middle finger while testing the cut of a dado blade.
I saw this in one of my woodworking mags a couple years ago, and I’m very happy it’s out on the market. Once I get my shop up and running, I’ll be adding it to my table saw - I would gladly pay $200 for a false alarm and keep all 10 digits.
What gotpasswords said about gloves (loose clothing, long hair, jewelery etc…)
I’m not convinced the blade would be ruined. The brake looks like soft aluminum, with holes drilled thru to make it even softer.
Is a saw motor AC? If it was DC you could use the sensor triggering a DC brake, instead of a physical one. Would stop the blade about as fast. The blade dropping down is all momentum.