You Gotta See this!

[Grumpy]

I thought about posting this in the Safety section because it is a safety thing.  However, I don't   think CAP really has anything to do with table saws.  But, it's really a neat safety device and you gotta see it to believe it.

http://www.youtube.com/watch_popup?v=E3mzhvMgrLE&NR=1

[NIN]

There was _NO_WAY_ I could watch that whole thing. *shudder*

[a2capt]

It's absolutely nothing. They use a hotdog and there is plenty of warning to the actual test....

[Eclipse]

Man, that tears the heck out of the saw - better make sure your wood is dry.

Hot dog?  Watch until the end...

[heliodoc]

Good call, Grumpy!

Whether or not CAP has anything to do with table saws or not....

How many in the CAP membership own and operate chainsaws and table saws either as a hobby or real life occupation(s) such as carpenters, foresters, woodworkers, etc?

Still a good safety call.......This has been covered by the Real Military when there were more MWR hobby shops and some shops in general BITD

So CAP could use a little dose of reality outside of aviation.....one false move with any of these tools and its a LONG road to hoe getting a flying medical back depending on severity of injuries with these.  Although slicing fingers probably does not constitute loss of a medical......loss of digits and possible time off work and depending onn the occupation....some remedial training......

Sound familiar, CAP??

[NIN]

It's absolutely nothing. They use a hotdog and there is plenty of warning to the actual test....

Yeah, I stopped when they said the guy was gonna use his own finger. 

[Capt_Redfox30]

I was at a safety conference this past March for school and a vendor was doing a demonstration of this piece of equipment.  It was very interesting to see, he did use his finger and yes it was still there at the end of the day. 

[Grumpy]

I was the same way, kinda squinted when I watched it but there's nothing shocking with what you're going to see.  They say the device costs $60 and it does tear up the saw by stopping it so fast but then like the guy says, "consider the alternative".

[vmstan]

I actually used to work for a company that sold these things. One of our salesmen did the demo with me and used his finger, without telling me what the hell he was doing. I about had a heart attack. Pretty cool stuff.

[mynetdude]

NIce! Nice to know I can work with wood/table saws without too much fear of getting my fingers cut off FWIW I don't have great depth perception so this device is a finger saver

Like anything else man made, machine it can fail so its not something I would wholly trust to keep me out of trouble.

They don't explain how it works though, what causes the device to activate?

[a2capt]

Yeah, they do. Voltage drop. The blade is charged with voltage and it's isolated. Voltage does what voltage does. Tries to find a path to ground. When it starts to drain, a voltage drop is detected and that activates the mechanism.

The blade can be looked at as a capacitor, and it's being charged at a rate that is far slower than the targeted scenario would drain it, thus the drop is detected. I would imagine that if a nail were in the board being cut and the nail is in contact with the table surface, that would activate it, too.

$60 .. for the blade and the speed brake. Think of it as a fuse.

[mynetdude]

Yeah, they do. Voltage drop. The blade is charged with voltage and it's isolated. Voltage does what voltage does. Tries to find a path to ground. When it starts to drain, a voltage drop is detected and that activates the mechanism.

The blade can be looked at as a capacitor, and it's being charged at a rate that is far slower than the targeted scenario would drain it, thus the drop is detected. I would imagine that if a nail were in the board being cut and the nail is in contact with the table surface, that would activate it, too.

$60 .. for the blade and the speed brake. Think of it as a fuse.

Ah ok, I misunderstood wy they were talking about wood being non-conductive vs your finger and didn't catch that.  Table saws aren't the only thing they use for cutting wood though, what about meat products? Although butchers probably use different saws to cut meat however wouldn't the same safety application be desired? If so, meat being conductive would have blades being damaged before the cut.

[Senior]

The block the saw stops in is made of aluminum.  The real finger
demonstration shows the aluminum welded to the carbide teeth.
If the blade is not deformed I bet the blade could be cleaned up and
resharpened.
Butchers use bandsaws.  A continuous band with teeth on it.  They
can cut fingers off, but my experience in metal working a bandsaw
seems tamer than a tablesaw.  Bandsaws don't usually cut at 5000
surface feet per minute, that is how a bandsaw is measured.

[jimmydeanno]

If the blade is not deformed I bet the blade could be cleaned up and
resharpened.

I can't say that I'd want to use any blade that made that sort of an impact.  Even if you can't see a deformity (obvious would be warping, missing teeth, etc) I wouldn't want to risk the possibility of it breaking apart while I'm trying to use it.  Blades are cheap enough.

[mynetdude]

If the blade is not deformed I bet the blade could be cleaned up and
resharpened.

I can't say that I'd want to use any blade that made that sort of an impact.  Even if you can't see a deformity (obvious would be warping, missing teeth, etc) I wouldn't want to risk the possibility of it breaking apart while I'm trying to use it.  Blades are cheap enough.

Yep this is how some of our aviation's accident histories went, nobody saw the broken blades on the jet engines.