Would you buy this safety device?

[Cliff Rohrabacher]

I think I'd prefer Arthur Dent's Safety Glasses.

They got progressively darker as something dangerous approached until they were completely opaque and dark.

This protected you from the ill effects of psychological trauma of the oncoming danger.

[Eric DeSilva]

What we really need is a device that can see several seconds into the future and then provide some sort of warning . That I would pay for!

Amen. Might help in Vegas too...

[Don Bullock]

...
What is really too bad about the Sawstop is that it braking works using the actual blade and not a sacrficial blade/gear/ring/etc. also mounted on the arbor.

Anthony, you have a super idea there. Perhaps some company out there might jump on it and produce such a system. It could work on just about any woodworking machine.

[Jeff Duncan]

I'm another vote in the no thanks camp. I've been working in and around woodworking shops for quite awhile now and the one thing that seems pretty common amongst injuries, is the speed with which they happen. Generally by the time you realize somethings wrong, it's too late. Products like the Sawstop work b/c they are simply faster than human reaction time.
Also although I never recommend having hands too close to a cutter, there are some operations I perform that put my hands within what would likely be considered the "danger zone". Thereby causing false alarms which would really create a more dangerous situation than without such alarm.
I'm all for devices that make equipment safer but I don't see this one being in that category. What we really need is someone to take a Sawstop type mechanism and engineer it into other equipment, like jointers and shapers etc.. Something that could stop a cutter in a split second, before the operator even knows he's hit it, is IMHO the best type of safety device.
JeffD

[Anthony Whitesell]

After thinking about it a little more (and for the company that snooping here for ideas), I think the arbor nut would need to be redesigned. If the nut tightens in the direction of the load (tightens clockwise, spins CCW, load would be CW), If the shaft stopped suddenly, then the load from the spinning blade may try to loosen the nut. I'm just a mechanically inclined EE and maybe an actaul ME would have a solution.

[Matt Meiser]

Anthony, I've heard that problem mentioned as a possibility when someone uses a VFD on a table saw. Maybe a solution could be as simple as adding a small pin on the arbor that engages a hole in the blade. This seems like a modification that could be made to the blade even at home. They could just supply a small jig that has a drill bushing? If its was even an issue, they could have you drill two holes exactly opposite each other to prevent affecting balance.

On the original question, I would have to vote no for many of the reasons already stated. Just shutting down power wouldn't have prevented the accident I had with a router. And I think any effectiveness would be entirely dependent on the installation.

I've worked around equipment with light curtains. I'm not a safety expert, but thinking back it seems like they are usually placed far enough back that you couldn't get to anything dangerous before its danger is reduced or eliminated. And fast moving things--even things like robots that can be stopped in a lot less time than a spinning blade--are protected by gates. Some of the gates even have electromagnetic locks that engage when the equipment is in auto.

[Tony Bilello]

A zone alarm can be a distraction. What if you are making an unusual cut and start outside the zone ( no lalrm) then you enter the zone and have an alarm when you are partly into your cut? Lots of different scenarios there. Also, if you make difficult but samfe cuts with a jig it may be such that it would set off the zone alarm. So, you disable the alarm for these cuts, then the next cuts and after a while, you never use it.

[Cary Swoveland]

I question whether an alarm would be useful. One alternative is a device that almost instantly stops and/or withdraws the blade, ala Sawstop. Another approach, which I have not seen tried, is to almost instantly remove the operator. This could be done by having the operator wear a tethered harness attached to a spring, the latter held in an extended position with a thin wire that would be severed (e.g., with heat) when a proximity switch is triggered. Alternatively, the operator could wear an automotive-style airbag, again triggered by the proximity switch.

Cary

[Larry Browning]

What we really need is a device that can see several seconds into the future and then provide some sort of warning . That I would pay for!

But if it saw into the future that you were going to hurt yourself and gave a warning, you would then correct the situation, and then there would be no warning because you were never in danger. So the only time it actually would sound a warning is when you actually hurt yourself and you couldn't do anything about it. So your device that sees into the future might not be too effective either.

[Cliff Rohrabacher]

The safety zone could be set to the 3" rule or other specified distance.

My pinkies are often so close to the blade that there's no room for a gnat's wing in between. An alarm would startle the daylights out of me and ~ ~ ~ ~ ~ ~

[Mike McCann]

nope would not buy

[Glenn Howard]

How will this device distinguish a body part from the work piece? Without a method similar to the Saw Stop (which requires touch) I don't see how it could.

Without a brake, I doubt an alarm sounding if you get within 3 inches of the blade would do much more than startle you into moving ahead the other 3 inches.

The success of the Saw Stop is that the brake device is able to react more quickly than the human brain. This "danger zone" method still depends on the relatively slow reaction ability of the human brain.

Saw Stop got it right. Now if they're really smart, they're spending their R&D time while the patent is still in effect working on an aftermarket version that can be adapted to other brands of saws. And if they just got this idea from me, I'll expect a cut.

[Rod Sheridan]

My pinkies are often so close to the blade that there's no room for a gnat's wing in between. An alarm would startle the daylights out of me and ~ ~ ~ ~ ~ ~

Be careful Cliff, one under sized gnat's wing and you won't be able to type on SMC or FOG forums!

Regards, Rod.

[Charles Krieger]

Wow, this post generated a lot of good ideas and I want to thank all of you who contributed.

I was not thinking of a "light curtain" as I was aware of that technology and did not think that it would be practical for wood working equipment.

I originally posted here because I did not think I would buy such a device even if a practical model was built. I use the saw guard, riving knife, push blocks, sticks and hopefully caution.

The responses were really great. I especially like the idea of a break away pin, ring or some such to eliminate the cost of a new blade when the saw stop type of technology is used.

I do not work for any company, I am retired at age 70. I have no desire to start a company or do any engineering work for profit.

[Curt Harms]

I shake my head when I hear people lamenting about destroying a blade when a SawStop brake fires. If false firings were commonplace, perhaps that would be something to complain about. IT'S EASIER, CHEAPER AND LESS PAINFUL TO REPLACE 100 WW2 BLADES THAN 1 FINGER!!! That's presuming the finger(s) can be reattached.