Flesh sensing technolgy competition

[Jim Rimmer]

Has anyone read much about the Whirlwind technology for a flesh sensing guard for TS? I've only seen what is on their website. The guard seems to be touted as superior dust collection technology but also has a flesh sensing technology blade brake and looks like it can be retrofitted to existing saws. Didn't see anyhting about $$ but I didn't look too hard.

whirlwindtool.com/index.php?option=com_content&view=article&id=60&Itemid=50

Comments or opinions?

[Dan Friedrichs]

Electrically, I'm concerned that the way they stop the motor would be very hard on it.

Practically, I think it's useless - if I have a guard on my saw, I'm not likely to bump the guard with my hand and then keep on pushing as my hand goes under the guard and into the blade (feeling the guard touch my hand would be all the indication I need to pay attention).

SawStop is great because most people don't use the guard (or take it off for many types of cuts).

[Mike Circo]

It doesn't seem to stop quick enough to truly aid you. By the time it stops (one second!) your fingers are already gone.

Still kudos for at least trying to make things better. Maybe version 2.0 will stop quicker and not depend on the guard.

[Shane Black]

SawStop is great but it destroys the blade and the brake. You have to replace it if something happens. It stops in 5 milliseconds.
Whirlwind you can use on any saw but you are limited on the type of cuts you can do. It stops in 1/8 of a second.
Both are hard on the motor stopping so fast but it saves your fingers.
I don't use a guard on my cabinet saw just because of the limitations of cuts. I just have to be very alert when using the saw as everyone should be even with a flesh sensor.

[Dan Friedrichs]

Shane, if you touched the blade, would you really care about the cost of a blade and brake? It's nothing.

Sawstop brakes the blade and disconnects the motor (not hard on the motor at all), while the Whirlwind apparently uses the motor to stop the blade - quite a bit different.

[Shane Black]

I would rather have my fingers than worry about the blade!! Thousands on hospital bills or hundreds on blade and brake? Tough question!

[Dave Lehnert]

I would rather have my fingers than worry about the blade!! Thousands on hospital bills or hundreds on blade and brake? Tough question!

It would be my guess(Only a guess) there has been more damaged blades due to other things triggering the brake than a finger (hitting your miter guage, staple in the wood etc...) Thankful to have it if it was your finger, mad if it was a staple.

My first thought would be the Sawstop would be better as it works without any guard in place. The #1 reason the accident happens in the first place is people don't take the time to put blade guards on.
But is an option if you want to make your old saw safer.

I bet in 5 years we will see other safety features like Sawstop pop up on market.

[Bill Edwards(2)]

It doesn't seem to stop quick enough to truly aid you. By the time it stops (one second!) your fingers are already gone.

It's an 1/8 of a second.

And when they do the hot dog test it doesn't need stitchs.

You don't have to touch the guard to set it off, but if that's all it would take to stop
someone from hurting themselves, maybe they should use a guard.

And the guard works for all kinds of cutting..

[Lee Schierer]

It is good to see other minds start to work on this problem. Competition is always good. Stopping saws is like skinning a cat, there are probably more than one way to do it.

It looks like it still requires some level of adjustment on the part of the operator to keep the safety aspects at their peak level of protection. As long as the various adjustments are made and made properly the safety system will work as advertised. Will everyone make those adjustments, I think not.

The LED's in the guard were a nice feature, but may block your vision if you are trying to cut to a specific mark on a board.

I've often wondered why sawstop doesn't just drop the blade below the table when it triggers, but I suspect their design relies upon the torque transfer into the aluminum block to pull the blade down.

[John Coloccia]

It is good to see other minds start to work on this problem. Competition is always good. Stopping saws is like skinning a cat, there are probably more than one way to do it.

It looks like it still requires some level of adjustment on the part of the operator to keep the safety aspects at their peak level of protection. As long as the various adjustments are made and made properly the safety system will work as advertised. Will everyone make those adjustments, I think not.

The LED's in the guard were a nice feature, but may block your vision if you are trying to cut to a specific mark on a board.

I've often wondered why sawstop doesn't just drop the blade below the table when it triggers, but I suspect their design relies upon the torque transfer into the aluminum block to pull the blade down.

Looking at it as an engineer, my guess is that dropping below the table is nothing more than a way to dissipate all of that energy. It looks to me like when the brake fires, there's a great deal of force on the arbor. This is easier to see if you imagine just a stick with a hole in the middle. The bottom is trapped by the brake, and you're pushing on top trying to rotate it....it will be trying to bend the arbor. An alternate way of looking at it is without the arbor, the blade would shoot forward like a wheel. The only thing keeping it from doing so is the arbor.

My guess is that allowing the assembly to slam down below the table is just a means of spreading that energy out over a longer time to keep the arbor from bending.

The problem with any guard based system is that in a working shop, I sometimes work without the guard....maybe 25% of the time I don't use the guard for various reasons. I'm not ripping without the guard...usually, I'm using a crosscut fence or some sort of jig so the danger is much reduced to begin with. Still, I like having the added bit of protection there. Given a choice between no additional protection and some additional protection, I'll take some protection I guess. Better than nothing.

But if Whirlwind can be retrofitted, then that's at least some level of protection probably most of the time. I have to say, though, that he's not doing himself any favors with the lame hot dog test he's posted. Anyone can clearly see that the only reason whatever was being pushed through there didn't get chopped in half is that he stopped pushing it through! When we do the SawStop demos at Woodcraft, we do it for real and push it through as fast as we can. We never end up with so much as a nick on the wiener. It's quite remarkable to witness in person.

125ms is FAR faster than what the WhirlWind hot dog test shows. It makes me wonder is the video is just an early prototype (in which case he should redo it for real because it's making his technology look very bad) or if the 125ms figure is inaccurate. I think 125ms is quick enough to save you from a "shove your finger through the blade accident". I don't think it will do anything for a kick-back accident, which is where a lot of injuries happen (where someone's hand is tossed into the blade). I'm not sure of the time scales involved so no way of guessing how SS performs for that kind of accident.

It also seems like WhirlWind depends on contacting the blade guard. That won't help at all if you're fingers are in front or behind the piece and under the guard, nor will it help if the guard isn't adjusted accurately.

I'm not trying to be down on this technology. I think it's a good thing. It adds another layer of protection to saws that don't already have it, and also probably some better dust collection. It's just not a head to head competitor with SS technology. Again, I really hope no one takes this as bashing WhirlWind. I'm just trying to give an honest assessment of what it is and isn't.

[David Weaver]

yes to the comments about the SS dropping due to the momentum. You can see it in slow motion on youtube.

[Myk Rian]

My concern is the trunions on most saws wouldn't hold up to the stresses involved when stopping the blade as SS does. That's a lot of energy.

[Jim Rimmer]

Many good points made here. John C., I agree with many of your points and am not a defender of Whirlwind (as you are not a basher). He does need to update his videos (that's why there is some discrepancy between 1 sec and 1/8 second trigger time); he does have a video where he does a climb cut with lots of caveats about don't do this at home - he is showing the anti-kickback control of the Whirlwind. Also, he seems to have been promoting initially as a superior dust collector