Whirlwind blade stopping tech.

[Stytooner]

Guys, I have noted on a couple other WW forums that threads have been posted about this inventor's idea. Dave Butler, the inventor, was wanting to alert folks that new technology may be on the horizon and possibly could use some feedback.
Here is the link to his website.

http://www.whirlwindtool.com/

I do notice some things about it, but none that are too difficult to remedy. One in particular bugs me and that is how does it work when the blade is tilted? Is it intended to only be used at 90 degrees.

My take on how it functions is kinda like a touch lamp. It appears to have a strip of tape there along the bottom. If so, then the major parts are on the motor itself to do the braking. He mentions that this is in the prototype stage and he want other manufacturers of saws to perhaps license it. I don't know how well that will work for him, but I think he deserves everything he can get from it.

The blade braking portion though is really the main innovation and will likely be compared to Saw Stop and I feel there really is not much comparison. Two totally different concepts.
What do you guys think?

[cabinetman]

I think it's a good concept, as the blade doesn't get trashed, and there's no module to replace. It seems sort of bulky around the blade. He says very thin strips can be cut against the fence, but I don't see a lot of room there for push sticks and a follow through.

Not being able to use it for bevel cuts is not a plus. I would think for an occasional user it may be OK, but for someone using the saw hours on end day after day, would not be my choice.

He's looking to get the idea bought, as he only has prototypes that aren't for sale.
.

[herb fellows]

He says it stops the blade in one second? Hold your finger out and count to one one thousand while imagining a 10 inch blade going through your finger. OUCH!
I'm not sure what the Sawstop figures are, but I am sure it is a lot faster than that.

[crokett]

Herb, I don't know about you, but I don't feed wood fast enough to cut through my finger in 1 second. At least I don't think I do, so assuming my finger isn't moving, the saw blade is only going to cut as far as I've fed it through. Of course, this assumes I didn't just trip and fall on a spinning blade.

I like the concept - you can retrofit existing saws and don't need to buy the SawStop.

[Salty]

My take on it is that it will stop the blade 'before' your finger gets to the teeth. There seems to be a zone around the blade that triggers it to stop. Maybe something less than 3" from the blade.
The Sawstop is triggered by the actual contact with the blade.
I too would be interested to know if it works on a tilt. Seems it would lend itself to using any blade and perhaps even dado blades.
If nothing else it may lead to some other designs. I'm thinking maybe one using laser sensors.

[Stytooner]

I don't really think that the technology behind it is intended to be used for things occurring at a normal feedrate. Maybe, but the guard being locked in position sort of precludes anything other than stock going into the blade.

Having the extra safety feature that turns off the saw is nice additional safety.

I really like the Estop on top, though it needs to be much bigger. Perhaps the entire front of the guard itself used as an estop door. Like we do with our saws down below. Much larger surface is easier to hit in a hurry.

As for the guard being locked into position over the stock, it can be done easily with a shark guard as well with a washer or a Ushaped shim used on the front stud. It would lock and hold the shark at whatever height you wanted to prevent your hand slipping under it. The reason I don't ship them with that is to remain OSHA compliant. According to them, tablesaw guarding must ride up and on top of the stock being cut. It is, however, open to interpretation a bit.

OSHA mentions in a letter that the Brett guard can be OSHA compliant with the additional splitter and pawls added. The Brett Guard locks in place over the stock and don't ride on it, so even OSHA has different interpretations.

The LED lighting inside is neat and can be added to any saws blade guard now. LED lights in different forms and shapes are available sometimes for less than a dollar or two that would work via batteries. His looks to be incorporated in the system, so no extra button to push there.
Nice.

[Hoover]

The blade wasn't damaged in the demonstration. I like that over the SawStop. The retrofitting idea is great. Hopefully the Whirlwind comes to market, I am definitely interested with this concept.

[phi1l]

Herb, I don't know about you, but I don't feed wood fast enough to cut through my finger in 1 second. At least I don't think I do, so assuming my finger isn't moving, the saw blade is only going to cut as far as I've fed it through. Of course, this assumes I didn't just trip and fall on a spinning blade.

I like the concept - you can retrofit existing saws and don't need to buy the SawStop.

Speaking from experience, (and unfortunately) this is wrong. In less than a blink the blade grabs your finger & pulls it in, much faster than you can react. I consider myself extremely fortunate to have the finger with a jagged ugly scar to prove it.

[LinuxRandal]

Guys, I have noted on a couple other WW forums that threads have been posted about this inventor's idea. Dave Butler, the inventor, was wanting to alert folks that new technology may be on the horizon and possibly could use some feedback.
Here is the link to his website.

http://www.whirlwindtool.com/

I do notice some things about it, but none that are too difficult to remedy. One in particular bugs me and that is how does it work when the blade is tilted? Is it intended to only be used at 90 degrees.

My take on how it functions is kinda like a touch lamp. It appears to have a strip of tape there along the bottom. If so, then the major parts are on the motor itself to do the braking. He mentions that this is in the prototype stage and he want other manufacturers of saws to perhaps license it. I don't know how well that will work for him, but I think he deserves everything he can get from it.

The blade braking portion though is really the main innovation and will likely be compared to Saw Stop and I feel there really is not much comparison. Two totally different concepts.
What do you guys think?

In the alternate mounting video, he mentions how it could be mounted so one could still use a "new" riving knife (not really a new invention guys).
It appears to be capacitance driven, like the Sawstop (may have patent issues, aka Steve Gass, a Lawyer, will probably request a review), but appears to be in the gaurd, NOT the blade. Still fails to show how the unit stops the blade, and a second is longer then Glass's unit (may help stop false triggers on Sawstops, if inexpensive enough).
The antikickback features, remind me of the Jimmy Jig.

Anyone who has read Steve Gass's account of why table saw companies didn't want to license this, knows this inventor may not have much luck either; ESPECIALLY, since his patents are only PENDING, NOT AWARDED.

[LCHIEN]

One second is a long time. I think typical feed rates for ripping and crosscutting are probably in the 0.5 to 2 feet per second range. Just imagine in your mind counting 1-one-thousand, 2-one-thousand while ripping a three foot board... I come up with about 3 seconds. which gives 1 foot per second. Worst case, If you are approaching the blade at 1 foot per second and want it to stop before you hit it then you need to trigger the stop mechanism about a foot away.

Now a very slowed blade after 1 second will still do less damage. The sawstop claim is that it stops the blade literally in milliseconds which is why the blade gets destroyed... the energy has got to go someplace. But 5 milliseconds at 1 foot per second feed rate is about .060 inches... that is a mere skin break but no severed fingers. Which is why the saw stop can afford to wait until you touch the blade.

The difference i see is that the sawstop is electrically coupled to the blade so that if you touch the blade it stops nearly instantly, but the whirlwind uses some proximity detection which is maybe (guessing now) part of the cover. So another advantage of the saw stop is it works without a cover whereas the whirlwind requries the cover. [text removed]

not counting the blade costs from triggereing and licensing issues, i think the sawstop is still probably superior technology for protection.

[crokett]

Speaking from experience, (and unfortunately) this is wrong. In less than a blink the blade grabs your finger & pulls it in, much faster than you can react. I consider myself extremely fortunate to have the finger with a jagged ugly scar to prove it.

Ok, I will stand corrected then. I've never gotten a finger that close. OTH, I did slice the tip of my pinky - just in front of the nail - off with a coping saw (yes, a coping saw) once so I believe you. Of course, it was literally on the last cut for that project.

[Stytooner]

I agree the SS is likely superior technology.
I also think that it is something other than the switch or the touch that would be under a patent. Those type switches have existed already for quite some time. I think the patent may be in the way the controls for the system connect to the motor and in the way the motor does the braking. Just guessing really, but that would seem logical to me.

I think the actual switch or sensor in SS is likely under patent because it is extremely fast.
I think this whirlwind would do well to develop this one to switch or sense and brake faster as well.
Plenty of fast acting electronics available for use in something like this. The 1 second for the motor brake is actually pretty fast for those.

He probably needs to choose a different name for his product as well. There have been Whirlwind cut off saws as long as I can remember. At least 30 years I think.
I remember maintaining one in a furniture plant where I worked. These are air operated saws with a foot pedal.
Step on the pedal and the over arm cover comes down to clamp the stock while the big 18" blade comes up from the bottom and cuts 2 by material in less than about a second per cycle.
He doesn't need to have a question mark there regarding trademark, especially since he may be up against SS for patent trodding.


I have often thought of another way the braking could be done. It also really isn't new technology. Have the motor engage the arbor with a worm gear or a gear like is on a starter motor on a car. Once the solenoid is triggered, the gear would disengage and then a brake caliber around the back of the blade would lock. Do that near simultaneous and you haven't destroyed a blade or harmed the motor. You would have to develop a switch or sensor though, but there is more than one way to do some things.

[LinuxRandal]

The Sawstop is also non-defeatable whereas the whirwind design seems to think there will be cases where the owner wants to defeat it, again, perhaps making it less safe.

Have you watched the videos showing how to cut wet lumber? The Sawstop can be shutoff, so it is defeatable.

[LCHIEN]

Have you watched the videos showing how to cut wet lumber? The Sawstop can be shutoff, so it is defeatable.

yeah i do remember that now...

[master53yoda]

After watching the tapes this unit appears to be mainly an above table dust-collection similar to a shark but without the ability to work with the blade angled. As far as stopping the blade it is nothing like a saw-stop saw as it is simply reversing the motor until stopped. This would take about 1 second and only allow about 10 full revolutions of the saw blade, more then enough to remove a finger. His main sales pitch is dust control and a margin of safety to keep your finger away from the blade, If the finger gets to the blade it won't stop the blade from taking off the finger as a saw-stop will. There doesn't appear to be any new technology near what has been used in the saw stop.

The saw-stop stops the blade in less then 1/4 of 1 blade revolution. How it senses the difference between a hot-dog and a board I don't know. The method of stopping the blade is by mechanically locking the blade into a block of aluminum. It probably also bends the arbor shaft, and tears up at least the outer bearing. that is why it is a little expensive to restore after an activation, about 600 to $1000 from what i've been able to find.

Much cheaper then a new finger.

my 2 cents worth.