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Niki

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From reading in some "across the pond" forums, it cost some $3,500 and after every cut of a "hot dog
' you have to change all the mechanism for some $300.
There was some interesting argument; when you are pushing your fingers, at normal feeding speed, (controlled and deliberately) into the blade, it leaves a scratch. But, what if your hand slides into the blade uncontrolled and at much higher speed....

I think that usually accidents happan when something is getting out of control and in a rush. I believe that nobody will push his hand deliberatly into a blade.

IMHO, safety is in the HEAD, not in the BLADE

niki
 

Scrit

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Mike.C":2iq4sd3j said:
But will it make "DADO BLADES" any safer? :lol: oops sorry.
Actually yes, but you do have to use their own set I've been told. Why I'm not sure. For rebates a spindle moulder is still a lot safer IMHO and through housings aren't iused on the best quality or production work, so.......

As a saw it has many of the features we've taken for granted in Europe for years - overhead guard, braked motor, riving knife mounted on the trunnion - pity the fence system is so poor (no short rip fence means that you'll potentially suffer kickbacks when ripping) and the lack of a sliding table option is a minus as well.

Niki":2iq4sd3j said:
From reading in some "across the pond" forums, it cost some $3,500 and after every cut of a "hot dog
' you have to change all the mechanism for some $300.
OK, but how much is an amputation going to cost you (playing devil's advocate here)

Scrit
 

ike

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According to their own guff a replacement 'cartridge' is 80 bucks or so. Dunno if the blade would survive intact with all it's teeth after jamming a lump of metal into it though.

What I wondered is how it was tested and calibrated - on animal parts, pigs trotters maybe?, or with a very brave (or stupid) test engineer's digits? Is thre a natural variation in electrical conductivity of different bodies. Do environmental conditions such as humidity have an effect. Do any or all of these variation combine to change the efficacy of the device and it's reliability?.

It does appear to be an clever bit of design, but would you trust it to work?.

Ike
 

Scrit

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ike":h6d256r2 said:
What I wondered is how it was tested and calibrated - on animal parts, pigs trotters maybe?, or with a very brave (or stupid) test engineer's digits? .....

.....It does appear to be an clever bit of design, but would you trust it to work?.
I've read elsewhere that it works in a similar manner to an RCD - the current balance principle. I just wonder how well it would do in a salt-spray air environment, like by the seaside. And NO I somehow don't think I'd trust it...... :roll:

Scrit
 

Nick W

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Niki":2wmu55z7 said:
I think that usually accidents happan when something is getting out of control and in a rush.
Take a look at the Hot Dog demo movie on thispage. The sausage is moving quite fast when it hits the blade. As someone who has fed skin and bone to his Tablesaw :oops: and planer :oops: :oops: :oops: (not at the same time though) I would be glad to have any attachment that reduces any injuries even a little.

If they ever start making the units available as retrofit parts on other makes of machine, I will be first in the line.
 

ike

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Scrit wrote:

I've read elsewhere that it works in a similar manner to an RCD
The blade is acting as a capacitance sensor to distinguish between different materials (is that the same as an RCD works - I'm not sure?). Sensing electronics set the threshold at which a high current pulse melts a fuse wire (literally a 'hair' trigger that restrains a spring retraction/brake mechanism. All this integrated in the safety 'cartridge' hence the replacement cost.

Niki wrote:
If they ever start making the units available as retrofit parts on other makes of machine, I will be first in the line.
Pretty sure it can't ever be retrofit as the device appears to be an integral part of the overall saw design to retract the blade downwards.

So my other thought is how does the timber moisture content affect it? Would a soggy bit of firewood trigger it, or condensation?

If I were a nervous enough saw user to think it worth the dosh, I'd still not put all my trust in it saving me from horrific injury. Solid proof that it was as reliable as say, a car airbag - then I'd trust it.

Ike
 

Niki

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Hi Nick

I could not watch the video for some season, but even if it is fast, its still at the wood feeding speed, which is, in my opinion, lower than uncontrolled speed when my hand slips suddenly.

niki
 

Noel

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As far as I'm aware the blade needs replacing when the brake gets fired.
Noel
 

WellsWood

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I came across this a few weeks ago now and was wondering how long it would take for the subject to surface here. The best lowdown on it I've found is here

http://www.workbenchmagazine.com/main/wb295-cabinetsaws01.html

I have to admit I thought it was pretty impressive, not just because it stops the blade, but because of the clever way it uses the momentum in the blade to drag it almost instantly below the table.
I had no idea of the cost either of the saw or replacement cartridges (cost is always an issue of course), but look at it this way: How many of you would balk at the price of reloading the airbag in your car after it had saved your life? Not many I'll warrant. To continue the analagy, who do you know that drives recklessly because they have ABS?

Personally I think it's a great invention and look forward to point in the distant future when it is commonly fitted to all TSs, but I don't suppose it will be anytime soon.

Mark
 

engineer one

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interesting, this has been around in the states for about three years,
and was offered to many of the big manufacturers according to the
mags like fww that i read, but was rejected on the cost and
nih principle, so the guys had to do it themselves.

which is probably why it costs so much.

paul :wink:
 

JPEC

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Just watched the vids of this in action and i am impressed.
As for trusting it to work, i would gladly buy one and never have to find out!!
If i had the money for a top end table saw i would be quite happy to pay a bit extra for one of these.
Waste of good hotdogs though =P~

Julian
 

Noel

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engineer one":14morcnw said:
interesting, this has been around in the states for about three years,
and was offered to many of the big manufacturers according to the
mags like fww that i read, but was rejected on the cost and
nih principle, so the guys had to do it themselves.

which is probably why it costs so much.

paul :wink:
There was a bit more to it than that. When all the major manufacturers rejected the proposal the Sawstop people went to congress to try and get a bill passed that would make it mandatory that all TSs sold would have to have the technology fitted by law and Sawstop would have royalty agreements in place. This failed and caused a lot of disquiet amongst the manufacturers and the general machinery market.
So Sawstop went to Taiwan and built their own machines (there's also a contractors TS and no doubt other things are planned). After a few quality control problems they do seem to have carved out a niche in the higher end of the market. Similar marketing approach to Volvo some years back headlining the safety apects and producing the Hotdog video.
Putting aside the safety element by all accounts the machine is a well built TS. There have been a few reports of random firing but the company seems to have looked after owners when this has happened.
Personally I can't see many manufacturers (although Delta is rumoured to have looked at or designed something similar) either adopting the technology or designing something similar. Just too expensive for the general market.
I guess it's human nature to worry about the cost of a replacement cartridge and a new blade although a finger or limb saved puts things into perpective.

Noel
 

engineer one

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noel,
i always like to get some of the facts in order :lol:

we never actually think about the cost of our limbs until it is too late, and
then no price is ever enough.

interesting to see a company trying to get their product mandated by
government. latest information i have is that american accountants
post enron etc, want to reduce the amount of work they have to do
on an audit, because it takes too long, and is hard work.

these are the guys who try to tell you how to run your business,
but now they want to be able to reduce the risks they take even
more so that when it goes wrong, they have no responsibility at all.

nice work if you can get it :twisted: :twisted: :twisted:

anyway like an air bag, i am sure that in most cases, the charge
will never be used, so the question then is how long do they last
are they like fire extinguishers that need regular checking???

paul :wink:
 
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Scrit":28jhbqeu said:
ike":28jhbqeu said:
What I wondered is how it was tested and calibrated - on animal parts, pigs trotters maybe?, or with a very brave (or stupid) test engineer's digits? .....

.....It does appear to be an clever bit of design, but would you trust it to work?.
I've read elsewhere that it works in a similar manner to an RCD - the current balance principle. I just wonder how well it would do in a salt-spray air environment, like by the seaside. And NO I somehow don't think I'd trust it...... :roll:

Scrit
Hi Scrit
It works by injecting a 10KHz signal into the blade which is modulated when an object of some capacitance touches the blade. Wood does not have much capacitance and so the signal picked up by the monitoring electronics (Digital Signal Processors implemented in FPGAs) does not trigger the charge.
When a finger or other similar substance contacts the blade, the capitance of the body (sausage or whatever) causes a change in the 10KHz signal which is detected and causes the device to trigger.

There is full info on the National Instruments website as their Labview software package was used to create the system software - they presented it at our university which is where I first heard about it

here - see 4th paragraph
 

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