Saw Stop is here

[Kelly C. Hanna]

I wouldn't buy it. I don't like the delays or the legislation attempt they made. I am also surprised they are still afloat. In another thread on Woodnet, the guy who is in charge posts that they have had huge volumes of orders, yet we see no saws. I realize there are tons of things to consider and work out during a new product roll out, but I have a bad feeling about this one.

I think that if I had a new product and had millions of dollars in orders, I wouldn't have time or any reason to try and get a new law passed requiring this device on ALL new tablesaws sold in the USA. Also there must be a really good reason Delta, PM, Jet and everyone else passed on this idea. I guess we will see when they finally deliver one.

They use a hot dog BTW because of it's similarity to a finger. Somehow the blade is supposed to sense the electromagnetic pulses in the finger and the device then stops the blade.

[Mark Singer]

A lot of tablesaw accidents occur when the workpiece moves in an unexpected way (kickback or lateral/diagnol movement). When this happens it pulls the operators hand into the blade with the work piece. I don't think SawStop would help in this situation. Another common accident is when a push stick slips off the workpiece and the forward motion carries the operator and push stick into the blade. Again it probably won't help to have the SawStop. We should all be using enclosed "D" style push sticks. These type of passive safety devices are very helpful. I personally would not trust the technology of the SawStop.

[Rich Konopka]

[QUOTE=Kelly C. Hanna]I wouldn't buy it. I don't like the delays or the legislation attempt they made. QUOTE]

Kelly:

They are doing what every other big company does with the Goverment. LOBBY.
You have to admit that there is alot of threads and interest on the Saw Stop. To me that means there is a market.

Regards

[Kent Cori]

The real test will be how it works in a typical shop setting. Mark brings up several situations that occur all too frequently. If the SawStop will save an operator's hand from damage, word will spread and it will eventually be widely accepted. However, if it is not effective or the units fire without sufficient cause, the device will have a short commercial life.

[Chris Padilla]

Well, let's hope to hear from a real user...hopefully unbiased. I went ahead and sent a link to this thread to the info email address at Saw Stop. Hopefully they will peruse it.

Mark, I think you nailed it with typical situations in which an operator's hand might tangle with a moving saw blade. However, from what I understand, this device should still work fine in the situations you describe.

A sensor of some kind simply monitors the metal saw blade. The metal is a conductor, of course, and therefore can allow charge flow (a.k.a. current). This inventor must have found of sensor that reads the magnetic field the current generates (i.e. a coil maybe, an inductor--inductors store energy in a magnetic field) and found that the field changes depending on what contacts it. He also must have noticed that a human being touching it produces a particular field or field pattern and that it is unique enough to identify. Kudos to him!

I'm sure the overall amplitude or energy-content of these electircal signals is quite small. If I recall correctly from a college Psych class, the human body can produce microvolts of electricity (70 uV comes to mind) and that may be enough to sense through the saw blade when a finger contacts it. Obviously a piece of wood doesn't produce this or produces something very, very different or differerent enought to differentiate.

Notice that you need to turn the device off if you are cutting a conductor (i.e. aluminum, soft brass, etc.) on the TS. Why? Well, you are touching the metal and producing the same signal the sensor is looking for so it should trigger the moment you push the metal through the blade. Perhaps if you are wearing gloves, this might not happen while cutting a metal. Just a guess on my part.

Great discussion, Fellas...great.

[Tim Sproul]

Dennis,

I want to see the inventor actually spill some blood for his product and ram his own finger into the blade. That would be something!

chris,

I do believe Steve Gass, owner/inventor/investor or whatever of SawStop, has done this very thing........

Link

There is the link if you want to follow up and verify.....

[Chris Padilla]

Tim,

That comment was *mostly* tongue-in-cheek but it would certainly lend a lot of credibility to the device and the confidence of Mr. Gass.

Still, it would be hard for *anyone* to purposely put their finger into a deadly spinning blade!

[Steve Gass]

Chris, thanks for inviting me to participate in this thread. There are lots of great questions - I just wish you would have invited me sooner so I wasn't so far behind! I'll try to go through the various questions in order.


Kurt - Our saws are both left tilt. The prototype contractors saw we pictures on the website was a right tilt, but the production units are all left tilt.

David - You have to swap the cartridge when you change between regular and dado blade. This only takes a few seconds once the blade is already off and doesn't require any tools. The dado cartridge has a larger brake pawl to position the contact face next to the perimeter of the 8" blade and it is wider to accommodate the wide face of the dado.

Jay - Our saw is a significant step up in quality/size from a PM66 or a Unisaw. For instance, the cast iron table is 25% larger than either of those saws and the saw weighs over 100 pounds more than a PM66. The internal mechanism is far beefier and includes the European style riving knife and blade shroud dust collection. Most of the cost increase relative to the PM66 is in these mechanical features of the saw, not the SawStop system. The part of the saw that is SawStop adds about $100-150 to the price of the saw.

Rich - The table will have a support leg, we just didn't have it for the photo. One leg on the 36" fence and two on the 52".

Dennis - The system stops the blade fast enough that even though it doesn't react until you have actually touched the blade, in most cases the injury will be relatively minor - especially compared to what would happen without it. The blade normally stops in less than 1/200th of a second from the time you contact the blade and therefore the cut depth can be calculated by multiplying the velocity of your hand in feet per second times 1/200 - i.e. about 1/32nd of an inch at 1 ft/second.

Chris - I have actually touched the spinning saw blade twice to answer just this question. Fortunately, it turns out a hot dog is a pretty good standin for a finger - and cheap to boot!

Chris DeHut - The system monitors rotation of the blade during coast down and the system remains active until the blade stops. Therefore, you would have protection in the scenario you described where you shut the saw off with your leg and reached over the blade.

Terry - You can't use the bypass to get around changing to a dado cartridge. The system looks for proximity between the brake and the blade and will flash and error if they aren't close enough together. You can't use the bypass until you have the error cleared. The idea is that you don't want people to use the bypass to get around fixing some problem with the system.

Steven - The data simply doesn't support your argument that kickback is the leading cause of injury. In particular, the statistics show that about 90%+ of table saw injuries are lacerations or amputations. Now, in many of these cases, the precipitating event for contact with the blade may have been kickback, but it is the contact with the blade that is doing the vast majority of the harm. The system works just as effectively with a dado as it does with a regular blade.

The saw comes with a standard riving knife and a guard that is mounted to a spreader. The spreader and riving knife mount in the same socket, so the spreader goes up and down with the blade, just like the riving knife. Only difference is the spreader sticks above the blade to provide a place to mount the guard.

Jay - Although the prototype contractors saw pictured on our website doesn't show it, but the contractors saw will include the exact same guard riving knife system we use on the contractors saw. The change to implement this system on the contractors saw is one of the reasons why the contractors saw is a couple months behind the cabinet saw.

Chris - The blade is destroyed when the brake it triggered.

Mark - I don't believe the typical table saw accident happens all that fast. People regularly push three fingers right through the blade before they can flinch. Human reaction time is about 25-50 times slower than SawStop, so even if you are going fast, the accident will likely be far less significant with SawStop than without it.

Feel free to ask more questions and I'll try my best to answer them. I apologize for any questions I missed - it is a long thread. Feel free to remind me if I missed something you want an answer to and thanks for the interest.

Steve Gass, President
SawStop, LLC

[Chris Padilla]

Steve,

Thanks so much for participating in this discussion--I am sure your time committment is nearly unbearable with a new business venture. Also, Welcome to the Creek! We are a fine buncha folks here!

I look forward to the good discussion continuing. Are you ready for us to be firing at you from the hip???

[Chris DeHut]

Hi Steve,

Thanks for answering all of the questions. I am glad that the device is "in control" until the blade stops - that makes it much more useful.

Chris DeHut

[JayStPeter]

Steve,

I'm looking forward to seeing one. Are you (or at least your saws ) going to be on the show circuit this year?

Jay

[Jim Becker]

The data simply doesn't support your argument that kickback is the leading cause of injury. In particular, the statistics show that about 90%+ of table saw injuries are lacerations or amputations. Now, in many of these cases, the precipitating event for contact with the blade may have been kickback, but it is the contact with the blade that is doing the vast majority of the harm.

The only problem I see with this statistic is that it would obviously be skewed towards accidents that are "reported" and that is more likely when there is a cutting injury involved. For example, there are undoubtedly many folks who have experienced painful situations from kickback (myself included, but not recently, thank goodness) and did not go to the ER. Granted this may be trivializing things, but it's something that's important to acknowledge to keep the statistics honest. Your device does work to address the most severe injuries and that's good.

That said, thanks for contributing to the discussion. The questions and concerns are real and your willingness to address them directly is appreciated.

[Carole Valentine]

If the SawStop folk's were really interested in selling an inherintly safer product then they would design an American style cabinet saw with a proper riving knife with an attached, and detachable, guard.

My thoughts exactly!!!! If Delta or PM had offered a cabinet saw with a true riving knife and a decent, removable guard for $2500 I would have bought it in a heartbeat as opposed to the $1000 I spent on my lightly used Uni with 52" fence and accessories (not including the Uniguard I ordered today).

Personally I don't think I would buy the SS. The brake really only covers one scenario and most of the time that can be "covered" with a good guard.

[Robin Frierson]

Hi Steve, If a person wanted to order one of your saws today when would they actually be able to take delivery. BTW, I for one am glad your are offering the saw without a fence as I already got one. Everyone else wants to sell me a saw with a fence I dont need!! Thanks Robin Frierson

[Chris Padilla]

Robin,

Good point about the fence but it is a tad on the pricey side without the fence although it appears to be a well-made chunk of cast iron.