This is for metal workers too!

[eskimo]

I dont think I would be brave enough to test it?
If it is only $60 or so it will be a necessary feature

SAWSTOP in TimeWarp - YouTube (http://www.youtube.com/watch_popup?v=E3mzhvMgrLE&NR=1)

[bwal74]

Pardon the french but: ***** !!!
You'd really want hope the apprentice does his weekly maintenance checks properly.

[desbromilow]

Watched the footage but for some reason there was no sound at my end - the device appears to sefl destruct as part of the function - yes you've saved your finger, but then you'd have a few hours work putting the saw back to functional again afterwards. - not saying the tradeoff isn't worth it (finger versus delay), but am saying if the device was fitted, the liability issues would demand the unit was replaced by certified/approved people - not a hobbyist.

[Ueee]

That guy is nuts......i would be more worried about my guts where he was standing than my fingers......

I think the $60 is for a new blade and aluminum block, or maybe just the block. My blades are worth way more than $60..... What worries me is if the spindle of the saw is not isolated from the table of the saw......

For metal tooling it would only be of use if no oil or coolant was used.

Oh, and also, we heal, machines don't......

[pipeclay]

Not sure what the healing thing has to do with much.
Yes I suppose a stub gets a skin graft or flap put over,fingers you could allways just palm yourself.
Hope your not serious with that comment.
Machines can be repaired or replaced.

[Greg Q]

Ir that is for the table saw stop I have a couple of reservations: the feature adds many dollars to the price of a good cabinet saw, and an e-stop event costs around $200 for an average blade. So far that seems like a good trade-off to me, but it by no means renders a saw fool proof. Good riving knives, rip fence alignment and proper dust exraction and guarding would do more to prevent hospital visits than the saw stop.

The inventor did his best to sell his invention to saw makers. Eventually he tried to have it legislated as mandatory. Finally he enlisted his fellow trial lawyers into the scheme so that not having a stop mechanism was seen as akin to product negligence.

The entire saw-stop mechanism would be worth $500 to me as an added option on a table saw I think. Beyond that the value proposition is lacking.

Greg

[jack620]

I saw that device demonstrated at a woodworking show overseas about ten years ago (he used the sausage, not his finger). Back then the inventor was hoping it would soon be a standard fit on most table saws, however I've never seen a saw with one fitted.

I was told by an experienced woodie to never take my eyes off my thumbs when using the table saw, since nobody would voluntarily cut their own thumb off. That advice has served me well to date.

Given that metal is conductive, I can't see it having any potential for metalworking.

[Ueee]

Not sure what the healing thing has to do with much.
Yes I suppose a stub gets a skin graft or flap put over,fingers you could allways just palm yourself.
Hope your not serious with that comment.
Machines can be repaired or replaced.

Read the comment as you will.

When i did last did OHS regarding table saws and spindle moulders, there were far more accidents to a 3rd party than the operator, due to kickback resulting in the workpiece becoming a projectile.

I have probably spent upwards of 5000 hours on a panel saw and never even come close to cutting myself. Luck? no, proper training and correct techniques. I have however turned several pieces of timber into high speed projectiles, big enough and moving fast enough to seriously wound or even kill someone if they were standing in the wrong place. Whilst i agree that the item could save fingers, no safety device can replace training and common sense, and certainly not counteract stupidity.

PS i would like to see a test done at the speed of which an accident happens too even if only 3 or 4 teeth connect with your finger that would be enough to loose it.

[Stustoys]

Greg pretty much covers my response. That and the fact that the sawstop has a bypass.

I dont normally do this but for further reading sawstop - Woodwork Forums - Threads Tagged with sawstop (http://www.woodworkforums.com/tags/sawstop/)

This possibly the best?(its not like I've read them all)
http://www.woodworkforums.com/f153/sawstop-argument-68377/

enjoy :)

Stuart

[malb]

Ah, panel saws. After ten years around Brobos, Radial arms, SCMS's and normal table saws, I met my first panel saw.
Big differences there, some fool put a scribing blade ahead of the main blade, right where all my training and experience had taught me was was the safe approach limit to the blade for my hand.
Two years on, it hasn't bitten me yet. Tradies raised with the darn thing don't see a problem, because they have been trained from day that its there and sooner or later will be raised, but when you meet it after years of training and use with other gear, it is a definite potential hazard that can't be guarded

[Ueee]

Ah, panel saws. After ten years around Brobos, Radial arms, SCMS's and normal table saws, I met my first panel saw.
Big differences there, some fool put a scribing blade ahead of the main blade, right where all my training and experience had taught me was was the safe approach limit to the blade for my hand.
Two years on, it hasn't bitten me yet. Tradies raised with the darn thing don't see a problem, because they have been trained from day that its there and sooner or later will be raised, but when you meet it after years of training and use with other gear, it is a definite potential hazard that can't be guarded

I have seen several tradesman nick themselves on the scriber simply brushing waste away from the table. They know its there and yet they have still done it. Thats the stupidity i was talking about. For someone like yourself old habits die hard and it is very hard to change them when they have had many hours to root themselves. On my Felder the scriber runs off the main blade, so if it is bolted on it spins just below the table, ready to bite....:D

[Kon R]

Very clever design. :2tsup:

But then again if people were careful these would not be needed :p

lucky im a machinist!

[4-6-4]

Greetings Chaps I have seen this beast demonstrated on the computer and it does not grab me at all. I had 13 years as a student at RMIT pattern making school and the first thing we were taught was that you never ever ever put your fingers in the area of the table that has the acess hole to get at the blade. I have owned a table saw since the early 80,s at RMIT and at home or in a factory and I still have all 10 full digits. Another clue is to replace the metal or plastic cover where the blade comes up through the table with a thin plywood cover and then wind the blade up to its maximum height through the plywood. This eliminates the gap around the edge of the blade where bits of wood jam. If you have to tilt the blade make another cover and keep it for the next time. This thing looks as though it could do some serious damage to the saw I prefere to use caution not self destruction. Yours 4-6-4

[Stustoys]

Hi 4-6-4,
Not that I disagree with you but it could be argued that if it was there and you didnt put your finger in it then its cost to you would be $0. That assumes that in 25 years you had 0 false triggers.

Stuart(who is off to do some googling on sawstop false triggers)

[Ueee]

Hi 4-6-4,
Not that I disagree with you but it could be argued that if it was there and you didnt put your finger in it then its cost to you would be $0. That assumes that in 25 years you had 0 false triggers.

Stuart(who is off to do some googling on sawstop false triggers)

Well, the cost would be the original outlay.
But just to give you an idea in the commercial game, one false trigger with a set of stellite blades would cost you over $1k.....OUCH

[BobL]

This thing has been discussed ad nauseum in the other forums. Most of us are over it.

I played with one at our local woodworkers club a couple of years ago and watched about 20 cheap chinese blades destroyed using sausages as finger substitutes.

Yeah it works but I wouldn't get one.


. . . . PS i would like to see a test done at the speed of which an accident happens too even if only 3 or 4 teeth connect with your finger that would be enough to loose it.

That's what I thought as well when I saw the ginger way people were poking the sausages at the blade. I have since done the calculations based on the rated reaction time to stop and found it will be extremely difficult to make more than a 1 mm deep cut. You certainly will not lose any digits. The maths is somewhere on the site - I'll see if I can dig it up.

[China]

I can't beleive it took this long for the subject to appear on this forum

[Stustoys]

Well I googled but came up with nothing very useful(which wasnt a great surprise). Lots of talk about it and a few people claiming false triggers.

One thing someone did being up was that "the manufacturers won’t touch it for any amount of licensing loot. The reasons are many and some have been mentioned, but mainly you are including a feature which if it fails is a huge lawsuit waiting to happen."

Looking at that another way, I wonder how sawstop will go if or should I say when someone manages to cut their finger off. Then where will you get your replacement brakes?

Stuart

[SC_RUFCTR]

Good stuff and but if your using the correct procedures with your table saw you will never have a problem.
Like a lot of things they trying to sell this device from a fear/safety point of view.

....Push sticks, feather boards etc... how hard is that?

[Big Shed]

I can't beleive it took this long for the subject to appear on this forum

China this subject has been absolutely done to death on this forum but always in the area where it belongs, woodworking.

The problem with the Metalwork forum is that most people that frequent this seem to think it is the only forum on WWF, despite the name WoodWorkers Forum :rolleyes:

Sawstop is pushing very hard to have their device made mandatory on all table saws in the US, the most litigious nation on this earth, although we aren't far behind.

[eskimo]

apologies guys if this was old..I'd never seen it before (not that I recall anyway) and just thought it was recent and hence my posting of it.

but non the less..if it works then we should accept that it most likely will become a fixture on all saws?

One thing that does scare me though is what happens to that blade...and the possible results if the blade lets go towards the operator...seems to me that it may be better to lose a finger:oo:

[Ueee]

Eskimo,
Thanks for posting it, I have never seen it before.

I think we are all aware of the woodworking parts of this forum, but I know I have trouble keeping up with the metalworking side, and I'm sure some of us just aren't interested in woodworking, but that doesn't mean that things like the saw stop don't interest them. I stil stand by my belief that if if people are stupid enough to treat a saw without the respect it demands then they deserve to loose a finger. I know many of you may dissagree but I see this from a tradesmans point of view and not an untrained amateurs.

[BobL]

One thing that does scare me though is what happens to that blade...and the possible results if the blade lets go towards the operator...seems to me that it may be better to lose a finger:oo:

That's an interesting point of view because when I saw it being demonstrated I did not have the slightest concern about this.
They weren't exactly premium quality blades either.

[BobL]

I have since done the calculations based on the rated reaction time to stop and found it will be extremely difficult to make more than a 1 mm deep cut. You certainly will not lose any digits. The maths is somewhere on the site - I'll see if I can dig it up.

Here's the maths


The reaction time of Sawstop is supposed to be 1 ms.

This means via simple physics
1 if your hand is dropped under gravity from 0 distance above the saw it will stop by the time your hand has gone 0.0049 mm into the saw, ie a half a hairs width.
2 if your hand is dropped 10 cm above the saw it arrives at the blade doing 1.4 m/s and will stop by the time your hand has gone 1.4 mm into the blade, ie medium cut but leave finger intact.
3 if your hand is dropped 1 m above the saw it will be doing 4.4 m/s and stop by the time your hand has gone 4.4 mm into the blade, leave most of your finger intact.
4 the fastest speeds top black belt karate experts generate at the very end of the punch is about 7 m/s. This means a 7 mm deep cut, even that would possibly not even take your finger off completely.
5 to cut your finger (say 2 cm across) completely off would require a hand speed of 72 km/hr. I guess you could always hang your hand out of a car window and drive past the saw stop?

My guess is that probably case 3 and definitely cases 4 and 5 would shatter the bones in your fingers even if the blade was not moving.
So if you are stupid enough to push a still blade - well - need I say more?

I would like to see all these test confirmed with a pigs trotter - lets get mythbusters onto it!.


A "push and a slip" is unlikely to be worse than case two.

[China]

hi Big-Shed, Yeh there must be pages of discussion on the woodwork section, as I have most likely said before,what concerns me is the reliance safety devices that are not failsafe 100%, I have a friend in sa who dose a lot of work for schools here in S.A. and some of the so called safety add ons that are being fiited to machinery is a real concern e.g. anti kick back fingers on thicnessers. I'm sure the same must be occuring in the metal work field as well

[steran50]

Well I am definately not going to try it out. It would be a Good feature though to have on a Saw providing it never Fails.

[danielhobby]

i will simply say that there are quite a few very carefull operators out there that have lost a digit or two and up until that micro second of red mist they belonged to the" it wont happen to me" group.If you dont touch the blade the unit wont need replaceing(a little like seat belts or airbagsheh!?

[Stustoys]

How many airbags do you know with a bypass button?

[Ueee]

How many airbags do you know with a bypass button?

30 seconds with a computer these days....I got the VW guys to turn the passenger one off in my van cause i have Arthur in there a lot, and once Max fits in a forward seat i'll start training him up so i have 2 boys to do my job.....:D

[Michael G]

When I was first taught to use a saw many years ago one of the first things drummed in to me was to keep my fingers away from the line of the blade and using push sticks if necessary.
While an interesting device, the idea that it is needed (and should be mandatory) annoys me because it sounds like the alternative, thinking about what you are doing and using the correct technique, is too much of a burden to expect people to responsibly do. What ever happened to being responsible for your own safety?

Michael

[Stustoys]

30 seconds with a computer these days....I got the VW guys to turn the passenger one off in my van cause i have Arthur in there a lot, and once Max fits in a forward seat i'll start training him up so i have 2 boys to do my job.....:D
Well I was going to add "for the driver" as in some more enlightened countries there is a bypass for the front passenger airbags in the glove box. But as we in Australia are so stupid and children under XX(cant remember) aren't allowed in the front seat we cant be trusted to have said bypass. I'm a little surprised the VW guys did it, but then the rules may have changed since last had anything to do with such things.

Maybe we should mandate sawstop but I'd put it a long way down the list. We could always call table sawing an extreme sport then we could have competitions to see who could do a tripple back barspin tailwhip no footed can can losing point for how far the work comes off the fence with a multiplier for how high we have the blade out of the table .

Two lines that made me snigger a little while googling for this post "XXXXX's last fatal jump", I'm pretty sure it would have in fact have been his first fatal jump.

"A British climber plunged 130ft to his death" "The 44-year-old man who was not wearing a protective helmet", would be a very lucky day that a helmet saved you from 130ft


Stuart

[BobL]

i will simply say that there are quite a few very carefull operators out there that have lost a digit or two and up until that micro second of red mist they belonged to the" it wont happen to me" group.If you dont touch the blade the unit wont need replaceing(a little like seat belts or airbagsheh!?

A friend of our family worked for nearly 40 years in cabinet making with no workplace injuries other than a few splinters. He was also known by his apprentices as a bit of a safety nazi. A few days before he retired he was cutting up some small pieces with a small table saw . When he finished cutting he switched off the saw and went to flick a couple of small bits of wood off the table and ended up taking two fingers off. It's that quick. It ruined the first few months of his retirement as he and his wife had extensive travel plans leaving Australia the day after he retired.

[Stustoys]

Hi Bob,
I wonder what saw stop would have done in that instance? Anyone know?

Stuart

p.s. I had an uncle that worked for himself for over 20 years with out a scratch. Within a couple of year(?) he'd lost the best parts of three fingers and a thumb in two accidents on a spindle molder(isnt that what table routers are called?)

p.p.s. I guess I should add his made wooden furiture

[jack620]

The spindle moulder is the scariest machine ever made. I reckon mine is out to get me.

[BobL]

Hi Bob,
I wonder what saw stop would have done in that instance? Anyone know?


Did you see my calculation results above - cut depth is related to speed. A simple flick wouldn't be more than about 1 m's so he would have received a ~1 mm skin puncture. The sawstop reaction time is so quick the digit has to be traveling at karate punch speed to remove a digit.

[Stustoys]

Hi Bob,
Sorry, what I meant was, would sawstop still trigger once the spindle is turned off? If so for how long? I've never seen anything about it monitoring the spindle speed. If it triggers when the spindle is off do you have to remember to put it on bypass every time when you are setting up?

Stuart

[BobL]

Hi Bob,
Sorry, what I meant was, would sawstop still trigger once the spindle is turned off? If so for how long? I've never seen anything about it monitoring the spindle speed. If it triggers when the spindle is off do you have to remember to put it on bypass every time when you are setting up?

Stuart

Good point!!!

I had a look around their website and couldn't find anything but what I did find was that the reaction time for Sawstop is now showing as 3 - 5 ms. This is not so good as the 1 ms I based my initial calcs on. It means a push and slip injury goes from a skin nick to the likelihood of a bone cut. Based on this it probably probably still not take a finger off but it's not as good as I first calculated.

Another thing I turned up was on the Wikipedia entry for Sawstop where they claim the blade stops in 1/8" of rotation.
My calc for this is as follows
3000 rpm = 50 rps
0.005 s x 50 = 0.25 rev
For a 12" blade 0.25 rev = 9" or rotation.
To get the claimed 1/8" rotation the reaction time needs to be 0.17 ms (can someone check this?)
However there is another factor and that is that the blade is pulled town and back at the same time it is being slowed down. This is probably more important than the rotational speed being slowed.
To do a more complete analysis would required a time stamped slomo video of the triggering event.
I've wasted more than enough time on this.

I also found a page with pictures of finger injuries
SawStop - The World's Leading Maker of Safe 10-inch Table Saws » Finger Saves (http://www.sawstop.com/finger-saves/)
Of course they are not going to show anything too bad.

[Acco]

Stu, I could be wrong here but I'm pretty sure I read or maybe heard at one of the demos at the Wood Show that the Brake sensing unit stays active till the blade has stopped moving

[eskimo]

How many airbags do you know with a bypass button?


at least 2 in my cruiser...a little switch that you can turn off the side airbags for driving on inclines....
factory fitted!!!

[Stustoys]

Another thing I turned up was on the Wikipedia entry for Sawstop where they claim the blade stops in 1/8" of rotation.
My calc for this is as follows
3000 rpm = 50 rps

I got as far as here and you lost me.

I assume the " in 1/8" is a typo?(or its possible I am misunderstanding completely)

50 x 0.125=400 So that 400 1/8th of a turn per second
1/400=0.0025. thats not a lot of time even if they mean from when the brake hits the blade(opposed to when it is triggered, which would be a little naughty)

Hi DJ,
Now you have me wondering how slow a speed it turns off.

Stuart

[Stustoys]

at least 2 in my cruiser...a little switch that you can turn off the side airbags for driving on inclines....
What!!!!!! just so long as you remember to turn them on quickly if you roll it?
Now thats a new one.

Stuart

[BobL]

What concerns me about air bags was when I had my 2008 Hiace had a head on with a Honda Civic and totalled both cars neither car's air bag deployed. I thought that was what they were supposed to be for? I can understand maybe why mine didn't come on as I was probably only doing 10 kph but the other guy was doing about 50.

[Ueee]

Bob I have to agree with you, I had a Holden combo which I got rear ended in by a p plater in a vectra. We where in an 80 zone and I was stopped at lights she hit me that hard I was pushed about 20 feet and sandwiched between her and the car in front of me(not a good feeling when you have the brake pedal to the floor and you just won't stop).the seatbelt thingies went off , the entire contents of the van slammed against the cargo barrier and even the pen in my top pocket went flying. No airbags went off on either car though. They even have warning stickers on the underside of the sun visers about driving up gutters may set them off.....I hardly think so.

[eskimo]

What!!!!!! just so long as you remember to turn them on quickly if you roll it?
Now thats a new one.

Stuart


no dont have to do that..it...they come back on automatically when you get over 40kph ( i think it is)...

the car has sensors to deploy the bags if the car gets over a certain angle...hence the switch to prevent deployment as it is expected that one will put a 4WD in such situations on accasions.