Saw Stop is here

[Dino Makropoulos]

Yanno...I'll bet you can find a record of accidents happening in just about any line of work or hobby...even those using a safety device. It all boils down to one thing...NOT PAYING ENOUGH ATTENTION. Removing the responsibility is the wrong thing to do IMHO.

Hi kelly.

Just remember that not all people have the same level of attention.
And even if we do. We don't all have the same balance/reaction/charisma/skil/experiance /strength/ body structure.Plus,plus plus. And the Idea is how we can make woodworking safer to all.

Any one can go to any store and buy a table saw/radial arm saw /jointer/etc. That's what I did 20 plus years ago and bought a radial arm saw. To make a long story short, I almost kill my son with this thing.
I was using the saw for few years and I ALWAYS PAY ENOUGH ATTENTION
Do you have any idea how many accidents we have in US every day?

No one suggest that we should remove the responsibility from the users.
But what you saying is to remove the responsibility from the power tool manufactures.
Do you know that our government steps in some times and forces the manufactures to recall or improve the power tools?
And yes. They even recall my stupid radial arm saw.
IMHO It comes down to better education and smarter tools.
Then, anyone can enjoy woodworking and no just few that have nothing better to do but to make jocks about this unique and robust invention

[Kelly C. Hanna]

You have a great point about better education...smarter tools may help, but since the powers that be in that company tried to legislate the technology for ALL saws (which would have cost the industry a fortune), I can't agree with it.

I have had a few accidents in my time, but nothing I would EVER blame on any manufacturer or the product they made. If you slip on a wet floor, it's not the fault of the mopper or the bucket manufacturer or the owner of the place. It's a fact of life that accidents will happen. Those of us who experience them, learn from them....that's old school...new school involves removing responsiblity and lawsuits for those who don't and I disagree with both.

I think I will have to agree to disagree with you on this one, but that being said there are many safety improvements that I do agree with...most of them took much less time to get on the market and did not involve legislation.

[Dino Makropoulos]

You have a great point about better education...smarter tools may help, but since the powers that be in that company tried to legislate the technology for ALL saws (which would have cost the industry a fortune), I can't agree with it.

I have had a few accidents in my time, but nothing I would EVER blame on any manufacturer or the product they made. If you slip on a wet floor, it's not the fault of the mopper or the bucket manufacturer or the owner of the place. It's a fact of life that accidents will happen. Those of us who experience them, learn from them....that's old school...new school involves removing responsiblity and lawsuits for those who don't and I disagree with both.

I think I will have to agree to disagree with you on this one, but that being said there are many safety improvements that I do agree with...most of them took much less time to get on the market and did not involve legislation.

Kelly. You screw me up now.
Let me give you the other side.
Few years ago I offer (for free) few safety Ideas and designs to a CO.
They love it. They even ask me to be part of (safety Brainstorm sessions)
In few days they have a new dept. ASDG (advance safety design group)
In few weeks the whole thing was off due to the LAWYERS.
So, I can see why they was force that route.
Any way let's hope that the SAW STOP can be the right catalyst for safety.
And I can see where you coming from to.
Time to go to sleep.
YCF Dino

[Ian Barley]

IF you read the post I quoted when I wrote the previous reply it seems like the gentleman and most others imply that this device is just a nice little braking device

Chris - I was attempting to write the section from the mind of a goofy 13 year old who isn't gonna have to pay for the blade. I know that the blade is destroyed just like most of the interior of a modern car is "destroyed" when its airbags go off. Small price as I know you will agree.

If the blade grabs the push stick then the push stick becomes a pull stick

Dino - Your quoted incident was on a jointer and no details were given. If the guy was using an adequate push stick his hands would never have been close enough that he couldn't have removed them in time. The only way in which I can conceive of a TS blade "grabbing" a push stick is if it becomes jammed between a descending tooth and the end of the table. In this instance the force applied at the holding end of the push stick would be an upward rotation. Maybe in a really extreme case you could end up with a wrenched shoulder but you'd still be counting to ten.

I have alrady wittered on too much on this thread. I suspect that averybody who has read my posts has worked out my position. I'm gonna stop now before it gets stupifyingly boring.

[Steve Clardy]

Good idea? Yes.
Am I going to buy one? Probably not. I have a good saw.
Am I willing to have this shoved on me due to their marketing and government intervention? No
Will I buy one after my saw dies? Probably not due to their marketing.
Will I buy one after loosing some or all of my fingers? Don't know. I may not be able to do the work I do if that happens.
What happens when the cartridge shuts the saw down, destroying the blade, maybe breaking it, or throwing teeth in your direction, and the blade is chewing on the table insert, a metal one, maybe throwing metal into your eyes? Is it that fast of a shutdown this won't happen?
So. There are lots of pros and cons to consider before I would purchase one.
For now, I DOUBT that I would purchase their saw. I am not going to say I never will, at least for the moment.
Steve

[Dino Makropoulos]

Dino - Your quoted incident was on a jointer and no details were given. If the guy was using an adequate push stick his hands would never have been close enough that he couldn't have removed them in time. The only way in which I can conceive of a TS blade "grabbing" a push stick is if it becomes jammed between a descending tooth and the end of the table. In this instance the force applied at the holding end of the push stick would be an upward rotation. Maybe in a really extreme case you could end up with a wrenched shoulder but you'd still be counting to ten.

.

Sorry Ian. but I have to correct my mistake.And I hope you have your dinner by now.

Tool Type: Tablesaw
Experience Level: Beginner Injury Type: Needed Medical Attention
Accident Description
I was ripping a small board down when all fo the sudden my push stick broke, letting my hand slide right into the blade, since I was putting an extremely large amout of pressure on the board and push stick. After I had realized that my hand was gone, my arm was slipping into the blade as well. Surprisingly, I felt no pain in the first 4 seconds, but after about the 6th second, I was screaming. I managed to yell for help just before I passed out. My wife heard my call and took me to the hospital unconcience. After about 3 weeks in a coma, I woke up and started a 5 month recovery. To this day, I haven't found my arm or hand. Maybe one of my German Shepards ate them, I don't know for sure.
Advice to other Woodworkers
Don't be a dumby and put too much pressure on the cut
Tool Type: Tablesaw
Experience Level: Beginner Injury Type: Needed Medical Attention
Accident Description
Blade height too high. Guard off. push stick not big enough. Got nervous as i realized blade height too high. Tried to adjust hand on push stick. Next thing I know I'm off to the hospital with mangled ring finger, right hand. Sorry this is point form but one handed typing is a bitch as im discovering. (This just happened 3 1/2 hrs ago and my hand is bundled up, waiting for surgery tomorrow)
Advice to other Woodworkers
BLADE GUARD!!! BLADE GUARD!!! BLADE GUARD!!!
GOOD PUSH STICK!!! GOOD PUSH STICK!!! BUY ONE, DONT CHEAP OUT AND MAKE ONE, BUY SOMETHING DESIGNED FOR YOUR SAFETY


Tool Type: Tablesaw
Experience Level: Advanced Injury Type: Needed Medical Attention
Accident Description
The dado blade was in my saw and I needed to rip down a 2x6 real quick. So I changed the blade but did not bother to put the blade guard and splitter back in for this quick cut. Half way through the cut the wood bound up on the blade and kicked back. I was using a push stick but had the end of it in the palm of my hand and the force sent the push stick into my hand creating a 1/4" wide by 1 1/2" crater in my palm. Of course no one else was home so I had to knock on neighbors doors to find someone to take me to the hospital. I got 7 stiches and fortunatly the push stick went in between the tendons in my hand. When I got home I found blood covering my shop floor. I left it there to remind me to always use the guards.
Advice to other Woodworkers
Always use the guards and other safety devices with your tools, and make sure any push sticks handles are wide enough to hold properly and make sure your hand is around the stick and not the stick in your palm.
------------------------------------------------------------------------
Push sticks is not the answer.
The RIGHT push sticks. Like you said,and mandatory (safety) training before you buy any tool with rotating blade or knifes... Is the answer.
After my close call with the radial arm saw I see things differend Ian.
I thought I got over it, but the most recent incident with the teenager fire me up again for another twenty years.
To me, if the sawstop save few thousand fingers and only one hand per year,Is a good thing. And as a woodworker I support this Idea and concept. The list that the saw stop did allready (and I know first hand) Is to force the power tool Companies to RETHINK about safety.

YCF Dino

[mike lucas]

I would not pay much extra for the features that come with that saw.

I am wondering how many would play around and use up a cartridge before they realized it. That would be $70 down the drain. How about the fact that one becomes complacent and careless when they know they can not get hurt? Next thing you know, they find out the hard way that they can get hurt. And by then it is too late.



The idea sounds great, but I would be leery about it working properly over the long haul. My table saw is 12 years old, and I expect it to last well beyond my life time. Will such a gadget on the sawstop last as long as the saw itself should?



What happens if the company goes under in a year or 2? Will you be able to find replacement cartridges? How about repair cost 5, 10, or even 20 years from now?



How about the refinements to the system over the next few years? Will the people that are basic Ginny pigs now, have to upgrade at additional cost?



There are many questions that will need to be answered before something like this becomes the norm in workshops.

[mike lucas]

I would like to know where you all have agreed with the price of $2200. I can only find the price of $2499, plus $200 if you want the 5hp motor, (And that is a different for Me.) then $329 for the 50" fence and another $99 for the table and legs. So now my $1800 5 hp Powermatic starts looking like the best deal in the world. The Sawstop setup like mine would be $3126. I am not including the Beismeyer overhead blade guard, mobile base, and splitter. As everything but the splitter would cost the same extra on both saws.
$1326 more then what I paid for mine. That is one hellova lot of extra money.
I could just about buy the Oliver 10" jointer for that.

As for dust collection, I have read and heard others state that they would like a better dust pickup system. But I can not complain any with the way mine works. Maybe I have a better dust collector then those complaining. I don't know!

So now the only things on that saw that could make it better then my PM66 is the blade stop, blade brake, and rivving knife. I do not need a blade brake. I do not think that is at all important on a saw in a one man shop. And the rivving knife is not important due too me having the Beismeyer splitter that only takes a couple seconds to remove, and even quicker to insert.
So it comes down to the safety of the blade stop system. And $1300 is too much to even think of an upgrade.

There are too many other areas in a shop to improve safety, like dust collectors, air filter/cleaners, picking up after yourself, shields and guards on all cutting machines. Heck! Watch Norm and you can see him making every type of cut without any safety devises. Now I do not condone following Norm’s way of woodworking. He does this for viewing prepossess. Never the less, he could easily get hurt filming. I use all the safety I feel I can without getting stupid with devices. After all, there are limits to what you can do.

At one time in our History, windshields where not even an option, they are now mandatory. People do become complacent as more and more safety devices come into play.

[Dave Wright #2]

Been out this past weekend. Picking up on a few points:<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p>

Mike Lucas,

I’ve already given an opinion on the complacency issue. If car development had taken that logic we wouldn’t have soft dashboards, crumple zones, air bags, and many other design features that literally save thousands of lives every year.
SawStop is designing and specifying the brakes and overall system to have a long working life. We won’t really know if they’ll work perfectly for 20 years until, well, 20 years has passed. Worst case you could rewire the saw to bypass the brake.<o:p></o:p>
<o:p></o:p>

On upgrades: A big part of the delay in getting these saws to market is SawStop’s desire to NOT have an upgrade shortly after the initial release. They don’t want to use the public as beta testers. They do consider the cartridges to be replaceable though, and have put as much of the brains in each cartridge as is practical. That way software upgrades can be effected by simply shipping a new cartridge.<o:p></o:p>

<o:p></o:p>

$2200 (actually $2199) was the original preorder price. A couple months ago they had to bump it to $2499 because of increases from the factory. At this point it’s low volume manufacturing with substantial design and tooling expense. On the plus side, SawStop has no advertising budget and does not yet sell through dealers, so the purchase price goes straight to them and Geetech instead of woodworking magazines, home shows, and middlemen. They will have to sell quite a few saws before development costs have been recovered.<o:p></o:p>

<o:p></o:p>

Your math is accurate except I can’t find where you can order a new 5 HP PM66 for $1800. I get $2300 most places, which drops your difference to about $800. Everyone has to make their own decision regarding the value of the SawStop features. The value is certainly less for someone who already has a good cabinet saw.<o:p></o:p>

<o:p></o:p>

Steve Clardy,<o:p></o:p>

<o:p></o:p>

SawStop’s petition, for many woodworkers, hung the big bad brother image on them. Da’ man. No one tells us what to do, regardless of the value of their advice! IMO competing manufacturers telling their offshore manufacturers to not work with SawStop puts them in the same position. I’ve personally met the three owners and exchanged dozens of e-mails with Steve Gass. My business requires me to be a fair judge of character. I have not picked up the slightest hint of deception, interest in unfair trade practices, or any other ethical issues. They truly believe in the brake and simply want to see it made available to the woodworking public. Hindsight may prove that they were wrong, but they filed the petition because they thought it was the right thing to do for the woodworking industry and public. I don’t have a problem with that.<o:p></o:p>

<o:p></o:p>

The saw won’t thrash around and throw metal at you when it stops. The blade comes to a full stop and disappears below the table top in less than ¼ revolution. The carbide tips are sunk into an aluminum brake shoe. No chance of them flying around. This fast a stop requires approximately 150 HP of power (for a very short duration) – force that mostly comes from the saw’s momentum. The saw is designed to take this momentary pulse of force with no ill effect other than damage to the cartridge and blade. I won’t go into technical details unless asked, but have looked closely at the details and consider it to be a very elegant and thoughtful design.<o:p></o:p>

<o:p></o:p>

Christopher Pine,<o:p></o:p>

<o:p></o:p>

Yes, brake action demolishes the brake and blade. As I mentioned above, 150 HP of power, exerted opposite to the saw’s direction, is required to stop the blade in 0.005 seconds. Actually, that figure includes the sensing phase. The actual stop is even faster. A disk brake that clamped the blade sides instead of damaging the teeth would probably cost much more, be less reliable, stop the blade more slowly, and not pull the blade below the top.<o:p></o:p>

<o:p></o:p>

Best Regards to All,<o:p></o:p>

<o:p></o:p>

Dave

[Steve Clardy]

Ok Dave. Thanks for the response back on one of my questions.
But just had a thought here. Wonder why they did not go with a motor brake concept instead of their blade brake.
Having a motor brake would not damage a blade, and having to replace that blade and a cartridge.
I know this isn't apples to apples, but look at CMS saws and PC framer saws with the motor brakes. Same principal I believe. Seems they could have applied a stop cartridge on the motor casting, going inside and braking the armature. Armature having a special place built to withstand damage to it.
Just another thought. Maybe they have already thought of or done this.
Steve

[Dave Wright #2]

Good question Steve. I haven’t thought to ask it of Steve Gass so far. I’m fairly sure the answer would be that stopping the motor instead of the blade would substantially increase to cost of the saw, require many more custom parts (bad for maintenance if SawStop goes out of business), and increase the stop time.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p>

They stop the blade because that is the lightest/smallest component. Most of the momentary 150 HP force is spent stopping the blade alone in 0.005 seconds. The arbor “coasts” to a stop with no more force than can be transferred through the arbor nut. It might take 0.05 seconds to come to a full stop. The pulleys and motor take even longer to stop – limited by their greater mass and the fact that the pulley/belt system is not designed to transfer more than 5 HP or so.<o:p></o:p>

If you were to stop the whole shooting match at once, assuming the same 0.005 seconds goal, the forces would be astronomical. Let’s see…motor, pulleys, belts, arbor, and blade. Maybe 50 – 100 times the mass of the blade alone, so the required force would be 7500 – 15000 HP. Everything downstream of the motor would have to be built to withstand the related torque. The pulley/belt system and all shafts would have to be rated to match.<o:p></o:p>

Sorry to ramble. I think that stopping the blade is the most economical solution. It may be impossible to achieve the same performance by stopping the motor, and it for certain would be beyond my budget. SawStop's performance goal, a 0.005 second stop, still can result in a nasty bandaid cut. Reducing system performance even a little bit could quickly escalate the injury to emergency room level. Standard human reaction time in these instances might be 1/4 second. A standard motor brake takes over a second to bring a blade to a full stop. Whole different orders of magnitude than SawStop's objective.

Take Care,<o:p></o:p>
Dave

[JayStPeter]

Steve and Dave,

I don't see how you could stop that much momentum that quickly without a destructive impact. My CMS doesnt' stop quickly at all. Probably a good 5 or 6 revolutions from the motor. I have seen some pretty good stops out of electric motors, but all it takes is one tooth to go through your finger and it's gone.

As for cost, my feeling is that the SS compares more to the Laguna TS than a PM66. But, I've never seen the SS to verify. Just judging by features. The larger table, riving knife, and shroud DC in particular.

As for DC, I don't feel that DC on a standard cabinet saw (even a PM66) is great. Don't tell me that after cutting a bunch of wood there's not plenty of dust behind the saw. I certainly don't find it great on my Unisaw, even with the overarm guard. Better than a contractor saw, but still plenty of room for improvement. My feeling is that a shroud is the only way to improve on it.

Overall, I like the saw. If I didn't already have the Unisaw, I'd definitely put it as a contender. I do think they should offer an optional sliding table, since that seems like a safety feature to me also. I like the Laguna implementation of a US style saw with euro features including optional slider.

Jay

[Dave Wright #2]

http://www.sawmillcreek.org/attachme...chmentid=11537

Above is a picture of a brake cartridge that has done its job. Blade momentum was absorbed by the teeth sinking into the aluminum block and distortion of the block itself. You can see small curls of aluminum pulled up as the teeth went in. Look closely to note the holes that are now out-of-round. The middle of three large holes has crumpled almost completely. This force absorption is similar to what happens to car crumple zones during accidents.

Picture taken by my digital camera during my visit to IWF 2004 in Atlanta.

It may be worth noting that during IWF I saw several demostrations of the blade brake run on a single stock production saw. The saw appeared to take the hit without damage except to the blade and brake. No growing gravelly sound from abused bearings. These brake forces, BTW, are why the saw has arbor bearings that are considerably more massive than a PM66.

[Kelly C. Hanna]

I get an invalid link.

[Rich Konopka]

I don't understand why people are making a fuss over the cost of a cartridge and a blade. If an incident occurs and the saw stops resulting in a spent cartridge and a toasted blade isn't that a good thing?

Instead of a missing finger, hospital visit, doctor visits, and permanent injury. If you have the confidence that you willl not need the saw stop technology that that is good.

I personally think it is a great invention and should be noted. I'll be honest and admit I am still terrified of my saw and I totally respect it. But that doesn't mean I can't do anything stupid and hurt myself. Afterall, I am realtively new to this woodworking stuff and I can make mistakes. I also think that the long time woodworkers are just as vulnerable to injury either from rushing a cut or being complacent with safety.

I will definitely check out the Saw Stop next year when I graduate to the Cabinet Saw. I am looking forward to Dave's writeup.

Bring it on !!