SawStop, stops on contact with skin is coming to Europe soon!

[Jacob]

Still can't edit posts! Why is this?
Was going to add; it's a bit like feeding a wild animal behind bars; you could throw it in, but if not: would you hold the meat in your hand or offer it on the end of stick?

 

[Ed Weber]

The only way you know if a SS is actually safe is if you trigger it, which is caused by you behaving in an unsafe manner?
Work smart, work safe

 

[Jacob]

The only way you know if a SS is actually safe is if you trigger it, which is caused by you behaving in an unsafe manner?
Work smart, work safe

No, you use a sausage!
The trouble is you then have to replace bits and reset it, but then the only way you can test to see if it is now safe, is to trigger it again (with another sausage).

 

[Kevlar123]

Are these saw controversial? I've done a fair few shifts in the ED and table saw injuries completely put me off buying one, losing a digit would end my current career path. I was saving up for the festool with sawstop but I'm now considering the sawstop compact, apart from money do you lose anything substantial by buying a saw with sawstop, is it substantionally worse than Makita 2704N?

 

[Doug71]

Are these saw controversial? I've done a fair few shifts in the ED and table saw injuries completely put me off buying one, losing a digit would end my current career path. I was saving up for the festool with sawstop but I'm now considering the sawstop compact, apart from money do you lose anything substantial by buying a saw with sawstop, is it substantionally worse than Makita 2704N?

I think the full range of SawStop saws look well designed and decent quality. I would happily use any of them.

Basically the issue that a few seem to have with SawStop is they think people won't be as careful around the saw so there is more chance of finger contact with the blade, if this happens and for some reason the SawStop feature fails there will be a nasty accident which could have been avoided using basic safety practices like push sticks etc.

In my opinion an any extra safety feature is a good thing.

 

[Fitzroy]

No, you use a sausage!
The trouble is you then have to replace bits and reset it, but then the only way you can test to see if it is now safe, is to trigger it again (with another sausage).

Safety systems are typically constructed of multiple elements, at the most simple an input ie system/instrument that detects the unsafe condition, a control system which determines if the unsafe condition passes a certain set of condition, and an output which is triggered to take some executive action. Each of these element will have a PFD (probability of failure on demand) and combined they will result in the overall PFD of the safety system.

When design a safety system you will have a target PFD, for example you want the system to target 1 or fewer injurie in 100yrs of using the saw. Some analysis would provide you with the initiating frequency, ie saw use data indicates 1 incident per year of saw operation. So your safety system needs to function correctly 99/100 times or a target PFD of 1/100. The PFD of each element can be managed separately and tested for independently.

On SawStop there is a continual current running through the system which is used as the input, if this current isn't present ie the cartridge is not installed or the input fails either the saw won't run or the stop system operates with a false positive. As a result an unrevealed failure of the input is not possible and the input does not require periodic testing.

The control system can be configured to self test on every start-up. Inputting a false input signal and measuring for the correct output signal. If this test does not pass then the saw doesn't start. This continual testing would again result in a very low PFD. Additionally this control system could be part of the cartridge so that it is replaced on each system firing.

The output element of the system (the explosive charge that detonates on demand) obviously cannot be tested fully. However the system could again send a much reduced current through the firing pin (or similar) to test there is a continuous path and that the firing circuit is functional.

The only thing you are then left with is the potential failure for the explosives to ignite, if the saw had gotten totally soaked/immersed this may happen but the same failure cause would render all the other control systems and the saw as non functional.

You cannot demonstrate any system or thing is 100% safe, and nothing is. However, engineering safety design and failure is a well understood discipline that designs and manages risks many orders of magnitude greater than loosing a finger. I'm quite comfortable that these principals will have designed a system that has a PFD sufficiently low that any individual user need not fret about the system not working when needed.

Sorry a bit of an essay but may interest a few folks on some of the rudimental elements of safety system design.

Fitz.

 

[Inspector]

The output element of the system (the explosive charge that detonates on demand) obviously cannot be tested fully. However the system could again send a much reduced current through the firing pin (or similar) to test there is a continuous path and that the firing circuit is functional.

The only thing you are then left with is the potential failure for the explosives to ignite, if the saw had gotten totally soaked/immersed this may happen but the same failure cause would render all the other control systems and the saw as non functional.


Fitz.

Fitz an important correction to a misconception, probably because they call it a brake cartridge, implying a chemical device. There are NO explosives in the SawStop saws. The brake cartridge is a heavy compressed spring held that way by a fuse wire. When the system detects flesh it send electric current through the fuse wire, melting it, releasing the energy stored in the coiled spring, which pushes the aluminium brake into the spinning blade. It stops and drops it below the table in milliseconds.

I appreciate the insight into the PFD information.

Pete

 

[Chris West]

I think the full range of SawStop saws look well designed and decent quality. I would happily use any of them.

Basically the issue that a few seem to have with SawStop is they think people won't be as careful around the saw so there is more chance of finger contact with the blade, if this happens and for some reason the SawStop feature fails there will be a nasty accident which could have been avoided using basic safety practices like push sticks etc.

In my opinion an any extra safety feature is a good thing.

This phenomenon was seen when they first introduced safety belts. People drove less carefully. I suppose this could also happen with a SawStop product but frankly, I have used one for 10 years and never touched the blade while it was spinning. I have however, made the mistake of touching my aluminum mitre fence to the blade. The stop mechanism works on the capacitance in the body and this tiny current is transmitted through an aluminum fence thus activating the stop mechanism. Faster than you can see, the blade is immediately stopped and driven below the table. Entirely my fault for not checking the set up on the mitre fence. Nevertheless on those occassions when this happened, not the slightest nick is retained on the mitre fence. Unfortunately the blade can be damaged and a new SawStop brake cartridge is required.

 

[Jacob]

.......

Sorry a bit of an essay but may interest a few folks on some of the rudimental elements of safety system design.

Fitz.

Short essay here: rudimental safety with a woodwork machine is achieved simply by keeping your hands away from the cutters.
If anybody can't understand this and think they need Sawstop then they shouldn't be anywhere near any machine, bearing in mind that there will always be millions out there without sawstop.

 

[Fitzroy]

Short essay here: rudimental safety with a woodwork machine is achieved simply by keeping your hands away from the cutters.
If anybody can't understand this and think they need Sawstop then they shouldn't be anywhere near any machine, bearing in mind that there will always be millions out there without sawstop.

To err is human.

Other safety systems that competent persons should never need, but you’d be daft to go without.
- seatbelts
- terrain avoidance in aircraft
- high viz jackets for cyclists

Honestly no one buys or installs a safety device because they think they are incompetent without it, and the vast majority of safety systems will never be called on.

Fitz.

 

[Chris West]

Short essay here: rudimental safety with a woodwork machine is achieved simply by keeping your hands away from the cutters.
If anybody can't understand this and think they need Sawstop then they shouldn't be anywhere near any machine, bearing in mind that there will always be millions out there without sawstop.

Of course, anyone working around machinery must be prepared to follow some basic safety rules but table saw accidents still happen. No one intends to get hurt but the injuries that are sustained are life changing. There are few second chances when meat meets sharp metal spinning at 3500 rpm. Speaking as someone who was responsible for 40 years of operations around heavy industry equipment (I've seen the aftermath of too many accidents). When it comes to accident prevention around machinery, any sort of means to prevent contact, such as a guard or a mechanism, is far more effective than best intentions to work safely.

 

[Bingy man]

I mentioned earlier in this thread that with all the training, safety practices, common sense etc etc situations can arise that are outside of your normal safe working environment and I guarantee you will briefly think of this and other threads - @BarbaraT ,s accident last year and others like it. a stroke , heart attack, seizure, epileptic fit , or any other medical emergency could lead you to briefly lose control . Now I accept that this could happen with other power tools and machines that don’t as yet have saw stop or similar technology but I for one would not want to fall onto a spinning blade or hear of anyone else suffering the szme fate . No push sticks or safe working practice will help you Personally I think the sawstop technology or similar should be installed on all wood and metal working machinery . I certainly don’t advocate that all tools and machinery without sawstop be suddenly classed as dangerous just that a safer option be available. Just my opinion and the reason why I’m considering a saw stop instead of my current dewalt .

 

[Bingy man]

To err is human.

Other safety systems that competent persons should never need, but you’d be daft to go without.
- seatbelts
- terrain avoidance in aircraft
- high viz jackets for cyclists

Honestly no one buys or installs a safety device because they think they are incompetent without it, and the vast majority of safety systems will never be called on.

Fitz.

What about fall arrest devices ,dead man’s levers ,even the safety bar you have to hold in to start your petrol or electric lawn mower are all designed to prevent injury for whatever reason should you lose control. Most of us are indeed competent in using these tool but “What If “

 

[TRITON]

Still can't edit posts! Why is this?
Was going to add; it's a bit like feeding a wild animal behind bars; you could throw it in, but if not: would you hold the meat in your hand or offer it on the end of stick?

Nice analogy Jacob.

You do know, because of your long standing opinion that if you ever have an accident on a saw, you can never come back to UK workshop.

 

[TRITON]

high viz jackets for cyclists

You'd be surprised to learn but it has an opposite effect

" Last year, a study by the Queensland University of Technology found that high-visibility vests made cyclists look "less human" to other road users. Mr Bradshaw said the "off-the-cuff" Nationals motion was actually "creating a negative connotation around bike riders"."

 

[Kevlar123]

You'd be surprised to learn but it has an opposite effect

Less human, not less safe.

 

[Chris West]

Safety systems are typically constructed of multiple elements, at the most simple an input ie system/instrument that detects the unsafe condition, a control system which determines if the unsafe condition passes a certain set of condition, and an output which is triggered to take some executive action. Each of these element will have a PFD (probability of failure on demand) and combined they will result in the overall PFD of the safety system.

When design a safety system you will have a target PFD, for example you want the system to target 1 or fewer injurie in 100yrs of using the saw. Some analysis would provide you with the initiating frequency, ie saw use data indicates 1 incident per year of saw operation. So your safety system needs to function correctly 99/100 times or a target PFD of 1/100. The PFD of each element can be managed separately and tested for independently.

On SawStop there is a continual current running through the system which is used as the input, if this current isn't present ie the cartridge is not installed or the input fails either the saw won't run or the stop system operates with a false positive. As a result an unrevealed failure of the input is not possible and the input does not require periodic testing.

The control system can be configured to self test on every start-up. Inputting a false input signal and measuring for the correct output signal. If this test does not pass then the saw doesn't start. This continual testing would again result in a very low PFD. Additionally this control system could be part of the cartridge so that it is replaced on each system firing.

The output element of the system (the explosive charge that detonates on demand) obviously cannot be tested fully. However the system could again send a much reduced current through the firing pin (or similar) to test there is a continuous path and that the firing circuit is functional.

The only thing you are then left with is the potential failure for the explosives to ignite, if the saw had gotten totally soaked/immersed this may happen but the same failure cause would render all the other control systems and the saw as non functional.

You cannot demonstrate any system or thing is 100% safe, and nothing is. However, engineering safety design and failure is a well understood discipline that designs and manages risks many orders of magnitude greater than loosing a finger. I'm quite comfortable that these principals will have designed a system that has a PFD sufficiently low that any individual user need not fret about the system not working when needed.

Sorry a bit of an essay but may interest a few folks on some of the rudimental elements of safety system design.

Fitz.

Interesting and useful information on PFD. Folks, you do know that these saws have been in use in N. America for over 20 years?

 

[Chris West]

Everytime I get stuck behind a cyclist I have a negative connotation but this is a polite forum and I won't repeat it.

You'd be surprised to learn but it has an opposite effect

" Last year, a study by the Queensland University of Technology found that high-visibility vests made cyclists look "less human" to other road users. Mr Bradshaw said the "off-the-cuff" Nationals motion was actually "creating a negative connotation around bike riders"."I

 

[Jake]

Everytime I get stuck behind a cyclist I have a negative connotation but this is a polite forum and I won't repeat it.

Why though? Asking because I have a strong negative connotation with that sort of idiocy.

 

[SDev]

In deciding whether a safety measure is worth it one of the main considerations is risk vs harm; ie a very low risk occurrence with very high harm (such as permanent loss of a part of oneself) is surely worth extra measures such as SawStop. As has been pointed out, where humans are involved there is always the risk of mistakes, lapses in concentration or plain incompetence. I will be getting one as I could easily fall prey to one of the above if not all!