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Blade brake inventor aims to compete with SawStop

comments (0) September 1st, 2011 in blogs, videos

MKenney Matthew Kenney, senior editor
thumbs up 262 users recommend

Video Length: 3:25
Produced by: Whirlwind

I was floating through the woodworking corner of the internet recently when I came across a website for a tablesaw accessory called the Whirlwind. It caught me eye because it claims to be a type of flesh-sensing safety device, so I took a closer look. The videos are certainly intriguing. (Check out the one I've embedded here, and go the company's YouTube page for more.) So, I gave the device's inventor, David Butler, a call to get more information. Here is what I found out.

First the nitty gritty on how it works. The device is a blade guard with intergrated dust collection. The lower edge of the guard has a capacitance touch sensor on it. Say what? That type of sensor, according to Butler, is nothing new. In fact, it is the type of sensor used in those lamps that you can turn on and off by touching the lamp stand. When your flesh touches the sensor, an electo-magnetic brake that stops the motor from turning is triggered. That brake brings the blade to a complete standstill in about 1/8 of a second. The brake works by introducing an eletrical current to the saw's wiring, so there isn't any need to attach some physical braking device to the motor. When the brake is triggered, the blade stops spinning. It doesn't drop beneath the table and it doesn't get pushed into a brake pad (both things happen on a SawStop). So, all you have to do after the brake is thrown is restart the saw. The blade isn't damaged.


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Now for some answers to questions you might have. The brake can be overriden in case you want to cut a material that would otherwise set it off. Butler told me that any electically conducive material, like metal, would set off the brake if it were large enough, but he hasn't done any testing to see what the lower limit is (in terms of size--for example, would a staple set it off?). Why, because he isn't worried about an occasionaly false trigger--the blade isn't damaged, so there is no harm.

Also, it is possible to mount the Whirlwind so that you can use a dado set or make other non-through cuts with the saw and keep the device in place.

The device can be retrofitted to existing tablesaws and, withouth modification, can be incorporated into new tablesaws as they are manufactured. Butler has applied for patents and is attempting to strike licensing deals for both options (retrofit, orginal equipment). That means it's not on the market yet. So, you can't buy one now. And, of course, it might not ever make it to market.

Check out the Whirlwind website. Butler is going to release a new prototype very soon. And finally, a few questions for you. Would you use a device like this? Keep in mind that many of us do not use blade guards now. That's a question I'm asking myself. Also, do you want any type of flesh-sensing technology on your saw? Or do you believe (and a lot of folks do--just read some forum discussions) that if you always and rigorously follow the tried-and-true safety techniques for ripping, crosscutting, etc. that you'll never have a need for any type of blade brake? Let us know what you think in the comments below.

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