5 ms·

Another awesome safety system is the SawStop which uses the conductivity of skin to monitor for contact against the blade in a tablesaw. If it detects contact a

Another awesome safety system is the SawStop which uses the conductivity of skin to monitor for contact against the blade in a tablesaw. If it detects contact a small explosive charge goes off, instantly sending a block of aluminum into the path of the blade, stopping it dead. Even a serious accident like leaning with an elbow against a moving blade is likely to result in little more than the scratch from hitting a stationary sharp object rather than decapitation. Sadly the inventor couldn't convince the tablesaw manufacturers to use his invention for cost and/or liability reasons so he had to make his own. Their tablesaws themselves are relatively expensive but cost per accident is $100 for the charge plus whatever the blade costs, so basically $200 to prevent serious injury or death.

ArchOversight 5y ago
The biggest problem with the saw stop is that wood when it is even slightly moist can set it off. So on a worksite if you are using lumber that hasn't had adequate time to dry the saw stop would trip even without any limbs being in danger. Each time it would destroy itself, you would have to take the saw apart and change it which would cause a work stoppage. What irks me the most is that the SawStop owner tried to create legislation that would have required companies to use his product.
- akiselev 5y ago
  Do you know what moisture level sets it off? I didn't even think about that - it's easy to take Southern California's weather for granted. Here it's either pretty much ready from the lumberyard or you got it right off the mill's truck so it has to sit for a few days/weeks. The lobbying is off putting, yes, but at least his greedy self-interest would do some actual good instead of extracting evermore capital from everyone. Powertools inhabit this uncanny valley of dangerous equipment where they're cheap and accessible enough to the average joe (compared to CNC machining centers or forklifts or whatever) yet powerful enough to do some real damage. My understanding is that the primary reason the major manufacturers didn't want the SawStop wasn't cost but the fear that it would expose them to more liability by making the tools seem less dangerous. I really wish it achieves mass adoption so that the price drops even further.
  - VLM 5y ago
    Thankfully the patents are starting to expire in 2024. Nothing holds pack progress quite like the patent system. The problem with causing $300 of destruction and lost work time vs possibly saving a limb is there's no fine woodworking operation or framing carpentry operation that requires a table saw. Technically if you feel unsafe working with a table saw you can do absolutely everything very slowly and tediously with a router or router table or bandsaw, or manual tools like a chisel and hammer. Anyone concerned about safety doesn't use a saw stop, they use an entirely different technology than a table saw. If you make a table saw too safe or too expensive to actually use, people will simply use something else. The death toll may or may not be lower... From a marketing perspective, the people most likely to buy a saw stop because they're scared of table saws will save a lot of money by not buying either sawstop or table saw, and they'll cut dado slots using a hand held router (more dangerous in a different way) or break down plywood using a tracksaw (unholy expensive and many crushed foot injuries) or cut beveled edges on a router table or zillions of alternatives. Meanwhile the people who don't care about safety because they're not drinking on the job or they actually use the substantial amount of safety gear that makes a table saw perfectly safe OR they only do operations on the table saw that are inherently safe by nature (as opposed to relatively low risk operations, and some very high risk operations that people do anyway), will continue to save a lot of money by the combo of not being dumb and not buying sawstop. Finally the real dumb woodworkers who get drunk and get hurt or simply don't care, will continue to not care and not buy sawstop and will not live too much longer in a world either with sawstop or without table saws anyway, so its not like the world will net improve, the Darwin award winners will continue to win Darwin awards. So sawstop is a VERY hard sell. A similar problem is well manufactured table saws are safer than homemade table saws. The concept of "put a round blade on a motor" is too simple to legislate out of existence. So making table saws illegal wouldn't eliminate table saws it would just mean the homemade ones will make table saws, on average, more dangerous. Arguably, radial arm saws are more dangerous than table saws and "the marketplace" effectively eliminated those decades ago, so its not like the marketplace dislikes safety or whatever.
    - gknoy 5y ago
      > Meanwhile the people who don't care about safety because > they're [never doing unsafe things] This sounds an awful lot like suggesting that skilled users of firearms don't care at all about safety because no one's going to deliberately do stupid stuff. It seems farcical to me. Just as with firearm safety rules, they're there to protect people from the rare moments when we are inadvertently NOT careful. History has shown that people DO do stupid stuff because they were thinking about something else, or were tired, or distracted -- hence why every firearm is treated as loaded, even if you unloaded it, and why weapon safeties exist. For table saws, having a sawstop helps prevent situations that you don't have fill control over from having bad consequences. Of course you'd still use all the same safety measures you normally would without one.
- lcuff 5y ago
  Current saw stop units do have an over-ride switch so that if you know you're going to cut questionable wood, you can disable the safety mechanism for a series of cuts. (The safety mechanism comes back on if you power the table saw off, then back on.) But of course you don't know advance for sure if the piece of wood in hand will trigger the safety mechanism or not. Not everybody's cup of tea, but our ability to be 'present' is highly variable, both person-to-person, and one person over time. I'm a somewhat daydreamy sort of person, so I work to bring focus when I'm using power tools. As a hobbyist I walk out of my shop when I get tired, emotional, or otherwise distracted, but that's not an option for everyone.
  - yetihehe 5y ago
    "Check mode" with stopped saw and light/buzzer instead of brake would be pretty good for such cases (unless wood has some internal moisture).
- sharedfrog 5y ago
  > The biggest problem with the saw stop is that wood when it is even slightly moist can set it off. Is there any proof of this? From my understanding, that's a myth. Demonstrated here at about 3:00 https://www.youtube.com/watch?v=NV6Jhw0hhBI https://www.youtube.com/watch?v=NV6Jhw0hhBI
  - ta988 5y ago
    It is true, laser cut wood and burnt wood in general also sets it off. However on all saw stop saws I've used you can disable the safety when you have to cut those materials.
  - myself248 5y ago
    The one at our *kerspace has tripped numerous times on damp wood, laser-cut wood, shiny laminates that didn't register as metallic but apparently it was a full moon that day or something, etc. It's also saved a few legit fingers, so it's still a net win, but you've got to have pretty deep pockets to cover all the false trips.
    - sharedfrog 5y ago
      I see, thanks!
- bradknowles 5y ago
  Also, cutting anything that is metal or metal-coated, or otherwise conductive in any way. You’d be surprised at the number of materials you might want to cut on a table saw that are unexpectedly conductive.
ecpottinger 5y ago
Is there anyway to do it magnetically using inducted currents? I doubt you can stop the saw that way, but you should be able slow the blade down so it does not do as much damage.
- adrianN 5y ago
  A tablesaw goes through a finger as if it is nothing. Fingers can move at speeds of dozens of centimeters per second. So anything that takes longer a dozen microseconds to stop the blade will not be good enough to let you keep your finger.
CoastalCoder 5y ago
One thing I'm still unsure of regarding table saws: is there really much risk of injury if you follow all of the typically recommended safety practices? Every tablesaw injury I remember hearing about involved the operator failing to follow some of those guidelines.
- confidantlake 5y ago
  If you do everything right there is not much risk. But I have never met a human who does everything right 100% of the time.
- ta988 5y ago
  You can't avoid rare events like a wood piece breaking and things like that. I'm much more worried of angle grinder for example.
- zentiggr 5y ago
  This goes back to the basic point of safety work: Even the best trained, most attentive and careful operator can get into dangerous situations. There's no way to anticipate the moment that their attention might wander or some external circumstance might just force the situation.

ArchOversight 5y ago

The biggest problem with the saw stop is that wood when it is even slightly moist can set it off. So on a worksite if you are using lumber that hasn't had adequate time to dry the saw stop would trip even without any limbs being in danger. Each time it would destroy itself, you would have to take the saw apart and change it which would cause a work stoppage. What irks me the most is that the SawStop owner tried to create legislation that would have required companies to use his product.

akiselev 5y ago
Do you know what moisture level sets it off? I didn't even think about that - it's easy to take Southern California's weather for granted. Here it's either pretty much ready from the lumberyard or you got it right off the mill's truck so it has to sit for a few days/weeks. The lobbying is off putting, yes, but at least his greedy self-interest would do some actual good instead of extracting evermore capital from everyone. Powertools inhabit this uncanny valley of dangerous equipment where they're cheap and accessible enough to the average joe (compared to CNC machining centers or forklifts or whatever) yet powerful enough to do some real damage. My understanding is that the primary reason the major manufacturers didn't want the SawStop wasn't cost but the fear that it would expose them to more liability by making the tools seem less dangerous. I really wish it achieves mass adoption so that the price drops even further.
- VLM 5y ago
  Thankfully the patents are starting to expire in 2024. Nothing holds pack progress quite like the patent system. The problem with causing $300 of destruction and lost work time vs possibly saving a limb is there's no fine woodworking operation or framing carpentry operation that requires a table saw. Technically if you feel unsafe working with a table saw you can do absolutely everything very slowly and tediously with a router or router table or bandsaw, or manual tools like a chisel and hammer. Anyone concerned about safety doesn't use a saw stop, they use an entirely different technology than a table saw. If you make a table saw too safe or too expensive to actually use, people will simply use something else. The death toll may or may not be lower... From a marketing perspective, the people most likely to buy a saw stop because they're scared of table saws will save a lot of money by not buying either sawstop or table saw, and they'll cut dado slots using a hand held router (more dangerous in a different way) or break down plywood using a tracksaw (unholy expensive and many crushed foot injuries) or cut beveled edges on a router table or zillions of alternatives. Meanwhile the people who don't care about safety because they're not drinking on the job or they actually use the substantial amount of safety gear that makes a table saw perfectly safe OR they only do operations on the table saw that are inherently safe by nature (as opposed to relatively low risk operations, and some very high risk operations that people do anyway), will continue to save a lot of money by the combo of not being dumb and not buying sawstop. Finally the real dumb woodworkers who get drunk and get hurt or simply don't care, will continue to not care and not buy sawstop and will not live too much longer in a world either with sawstop or without table saws anyway, so its not like the world will net improve, the Darwin award winners will continue to win Darwin awards. So sawstop is a VERY hard sell. A similar problem is well manufactured table saws are safer than homemade table saws. The concept of "put a round blade on a motor" is too simple to legislate out of existence. So making table saws illegal wouldn't eliminate table saws it would just mean the homemade ones will make table saws, on average, more dangerous. Arguably, radial arm saws are more dangerous than table saws and "the marketplace" effectively eliminated those decades ago, so its not like the marketplace dislikes safety or whatever.
  - gknoy 5y ago
    > Meanwhile the people who don't care about safety because > they're [never doing unsafe things] This sounds an awful lot like suggesting that skilled users of firearms don't care at all about safety because no one's going to deliberately do stupid stuff. It seems farcical to me. Just as with firearm safety rules, they're there to protect people from the rare moments when we are inadvertently NOT careful. History has shown that people DO do stupid stuff because they were thinking about something else, or were tired, or distracted -- hence why every firearm is treated as loaded, even if you unloaded it, and why weapon safeties exist. For table saws, having a sawstop helps prevent situations that you don't have fill control over from having bad consequences. Of course you'd still use all the same safety measures you normally would without one.
lcuff 5y ago
Current saw stop units do have an over-ride switch so that if you know you're going to cut questionable wood, you can disable the safety mechanism for a series of cuts. (The safety mechanism comes back on if you power the table saw off, then back on.) But of course you don't know advance for sure if the piece of wood in hand will trigger the safety mechanism or not. Not everybody's cup of tea, but our ability to be 'present' is highly variable, both person-to-person, and one person over time. I'm a somewhat daydreamy sort of person, so I work to bring focus when I'm using power tools. As a hobbyist I walk out of my shop when I get tired, emotional, or otherwise distracted, but that's not an option for everyone.
- yetihehe 5y ago
  "Check mode" with stopped saw and light/buzzer instead of brake would be pretty good for such cases (unless wood has some internal moisture).
sharedfrog 5y ago
> The biggest problem with the saw stop is that wood when it is even slightly moist can set it off. Is there any proof of this? From my understanding, that's a myth. Demonstrated here at about 3:00 https://www.youtube.com/watch?v=NV6Jhw0hhBI https://www.youtube.com/watch?v=NV6Jhw0hhBI
- ta988 5y ago
  It is true, laser cut wood and burnt wood in general also sets it off. However on all saw stop saws I've used you can disable the safety when you have to cut those materials.
- myself248 5y ago
  The one at our *kerspace has tripped numerous times on damp wood, laser-cut wood, shiny laminates that didn't register as metallic but apparently it was a full moon that day or something, etc. It's also saved a few legit fingers, so it's still a net win, but you've got to have pretty deep pockets to cover all the false trips.
  - sharedfrog 5y ago
    I see, thanks!
bradknowles 5y ago
Also, cutting anything that is metal or metal-coated, or otherwise conductive in any way. You’d be surprised at the number of materials you might want to cut on a table saw that are unexpectedly conductive.

ecpottinger 5y ago

Is there anyway to do it magnetically using inducted currents? I doubt you can stop the saw that way, but you should be able slow the blade down so it does not do as much damage.

adrianN 5y ago
A tablesaw goes through a finger as if it is nothing. Fingers can move at speeds of dozens of centimeters per second. So anything that takes longer a dozen microseconds to stop the blade will not be good enough to let you keep your finger.

CoastalCoder 5y ago

One thing I'm still unsure of regarding table saws: is there really much risk of injury if you follow all of the typically recommended safety practices? Every tablesaw injury I remember hearing about involved the operator failing to follow some of those guidelines.

confidantlake 5y ago
If you do everything right there is not much risk. But I have never met a human who does everything right 100% of the time.
ta988 5y ago
You can't avoid rare events like a wood piece breaking and things like that. I'm much more worried of angle grinder for example.
zentiggr 5y ago
This goes back to the basic point of safety work: Even the best trained, most attentive and careful operator can get into dangerous situations. There's no way to anticipate the moment that their attention might wander or some external circumstance might just force the situation.