SawStop

[Hank Gillette]

If I were cutting off a finger every week, a $100 Forrest blade would be the least of my worries.

[David Hall]

I am certainly not a big fan of this type of regulations. However, someone did provide a source citation for the number of amputations. That was the Federal Consumer Safety Protection Commission. See

also understand that there would be few affordable cars with airbags if they were not required and that deployment of an airbag adds quite a bit to smaller accident repair costs. On the other hand a $250 to $500 Sawstop will pretty much eliminate the $200 tablesaw and it is doubtful one could be put onto a cheap tabletop saw anyhow. How many fewer people are simply not going to be able to realistically participate in the hobby if something like this is mandated. I am not sure that, even though I consider myself a conservative, I am ready to eliminate all regulartory aspects of government - I just would want to err on the side of "freedom" in this area.

Dave Hall

[Tom Veatch]

Kinda got to vote with David on this. To put a little finer (?) point on it, I see a place for regulatory interest in areas where the danger is insidious and/or non-apparent. I don't like the idea of government acting _in loco parentis_ or trying to protect me from myself in the presence of obvious danger.

Tom Veatch Wichita, KS USA

[Ba r r y]

Ever hit serious turbulence? The kind where the flight attendants strap in and make funny faces?

If you'd ever flown through some of it, you'd change your mind.

We don't even need to get into crashes like UAL 232, where half of the passengers actually survived a DC10 cartwheeling through a corn field.

Barry

[mark]

Yeah, on a smaller plane it makes sense. I've been in some pretty bad turbulance in that respect. Anything that affects a 737 in that way is enough to make you wish you had a full chest harness like the nascar guys. I know there's a reason for them, it's just that they look woefully inadequate. If you tumble through a cornfield, I guess you're probably not gonna get tossed out the windshield. My bet is you'd be strapped tightly to a chair that was no longer connected to anything. :)

[Upscale]

Yeah, I'm aware of that and I fully agree with you. Safety is one thing, forcing it on people mainly to make a profit or succeed in business is a whole new ballgame.

[Upscale]

Hey, no worries. After ten weeks you wouldn't need the sawstop or a new blade anymore. :)

[Ba r r y]

I've seen people tossed about a 747-200 in turbulence. Is that what you're calling small? The -400 is bigger, I know...

UAL232 was a DC10 that had the tail engine disintegrate and cut a bunch of hydraulic lines. Through some serious problem solving and the presence of an instructor pilot on the passenger manifest, the plane actually landed. Upon landing, it cartwheeled. Half of the passengers survived. If everyone had been flying around the cabin, not belted in at all, maybe the results might have been different?

More info:

Barry

[Old Nick]

On Tue, 16 Nov 2004 03:49:00 GMT, "mark" vaguely proposed a theory ......and in reply I say!:

remove ns from my header address to reply via email

To me there's a huge differnce between a helmet /seatbelt and a saw stop. A huge percentage of injuries to motorists are caused by somebody else. I would think that an overwhelming percent of saw accidents are caused purely by the operator.

***************************************************** Dogs are better than people.

People are better than dogs for only one purpose. And then it's only half of ofthe people. And _then_ most of them are only ordinary anyway. And then they have a headache.........

[David Hall]

Consumer Products Safety Commission

[cg]

As no one offered a little more explanation on how fast this saw-stop really stops, I would present some simple maths...

From their website they say they can stop a 4000 rpm blade in less than five (5) milliseconds. Now, the blade normally takes 60 seconds for 4000 rounds. In one millisecond, the blade would rotate 1/15 round... (that is one part of fifteen).

So, if the sawstop mechanism takes 5 milliseconds to stop, I would expect at most 5 x (1/15) ,that is, one-third of a full rev of the blade to plough thru before it stops.

Say, I'm ripping with a 24 teeth blade. In 1/3 rev, I would expect no more than 8 of those teeth to bite me. If I had been using a 60 teeth cuutoff blade, watch out! 1/3 of 60 is 20!

To be honest, I would reduce the fraction from 1/3 to 1/4 or

1/5 because I have not taken into account the deceleration... once the brake is applied, the blade is spinning down and it is not rotating at 4000 RPM during the entire 5 milliseconds. (So, how long it takes for brake shoes to engage? 1 millisec?)

Even then, for a 24 teeth ripper, 1/5 is 4+ teeth and for a 60 teeth cutoff, 1/5 is 12 teeth. Little consolation for me!

I wish the sawstop folks could give out details like these. In particular, they must already have exact figures for the rotation before complete stoppage. Instead of telling in terms of time (like milliseconds) it would be better to state the same in terms of percentage of a full rev of a 10" standard kerf blade spinning at 4000 RPM. Although I must agree there is more truth in their statement compared to claims like 3.25 HP routers on 115v, or 12" SP/ 1200 cfm with a 10" impeller 2 HP DC, and the like!

Afterall, they certainly have the brain to see through my simple math... don't they?

cg

to be flippant about the injury rates

[Edwin Pawlowski]

If a blade is rated at turning 4000 RPM, how fast is it turning while ripping pieces of 12/4 oak? or cutting 1/8" masonite?

What if they said it was a quarter of a blade rotation (say a 40T blade for this example) and you show some flesh on 11 teeth. Would that be grounds of a law suite?

Are you trying to calculate how far the blade will penetrate your hand? So many possible factors as to feed rate, blade speed, position of our hand, that it would not be easy to give a definitive answer and that would also leave them open to possible legal action. I think the more details they offer the more problems the are going to encounter. Ed

[David]

It doesn't just stop. It retracts under the table.

David

cg wrote:

to be flippant about the injury rates

[Tom Veatch]

Some more simple math - ignoring the retraction of the blade and the angle of the leading edge of the blade WRT direction of feed.

Assume a feed rate of 1 foot per second - a pretty brisk but not unreasonable feed for thin soft stock. In .005 seconds (5 milliseconds) the stock would travel .060 inches. Therefore you could expect the blade to cut into your hand/finger/whatever approximately 1/16 of an inch before the blade came to a stop. That depth of cut is independent of the number of teeth or rotational speed of the blade.

A 1/8" wide and 1/16" deep dado cut in your finger may not be a pleasant experience but it would more likely require a Band-Aid instead of a trip to the ER.

That doesn't mean I favor legislation requiring this sort of device. Likewise it doesn't mean I oppose legislation requiring this sort of device.

Tom Veatch Wichita, KS USA

[Ba r r y]

I'd like to see the saw for sale on the open market, but NOT legislated as a requirement.

Barry

[hex]

The other side effect to consider is that eliminating low end saws will not eliminate the use of saws by users who would otherwise use those low end saws. So the weekend warrier cannot get a table saw. What does she do? Why, uses or mis-uses a hand held circular saw. Which is more dangerous: Ripping a 2x4 down on a low end table saw or trying to halfway hold it on a couple of saw horses or a work-mate while forcing a circular saw into a bind?

My biggest gripe is that the SawStop folks are trying to get a government mandated monopoly. If they were pushing for liability reform to make it more feasible to get vendors to adopt the technology that would be fine.

hex

-30-

[J. Clarke]

FWIW, yesterday I was getting on the Interstate and at the onramp there was not one, but three cops doing nothing but checking for seat belt use. Apparently this was done statewide. Really wish that it all came out of the pockets of the politicians.

This is actually one of my objections to socialized medicine--once it starts getting expensive the state has an incentive to cut costs by eliminating sources of injury. Starts out with helmets and seat belts but where does it end?

[J. Clarke]

If you check the regs you'll find that before that seat comes loose whoever is in it is already dead--the g-load they have to take is beyond the endurance of the human body.

[J. Clarke]

In the shop at Hamilton Standard there was a hydraulic press. It had been there for more than 50 years and there had never been an injury associated with it. Nonetheless, the safety engineers decided that it needed a guard. In the next year there were five injuries caused by the guard.

"Required safety devices" don't always add safety.

[Ba r r y]

According to a cop I know, they find an awful lot besides unbuckled seatbelts a those stops.

Open beers, clouds of pot smoke in the car, expired registrations, emissions violations (CT's old system), defective equipment, OUI, illegal immigrants, unregistered weapons, stolen cars, bail jumpers, you name it.

Not to mention, the holy grail, the u-turner or runner. These are the folks who see the checkpoint and either speed right through or pull a u-turn and run.

Apparently, many drunk and stoned folks, along with those who can't be bothered to renew registrations and insurance, or show up in court, also don't wear seatbelts. Once you're stopped...

The more he told me, the more I realized that the checkpoints have little to do with safety.

Barry