This guy purposely caused kickback on his table saw to prove a point.
Make sure you watch what happens at 4:20 into the video.
He agrees with anyone who calls him an idiot.
That made me cringe. I won't argue the merits of calling the fellow an
idiot, but hopefully his video will drive home the point about using a
table saw properly.
Jon
Excellent vid, valuable lesson.
He's not an idiot, he just didn't have the control over the situation as he
expected. Shit happens, even with good intentions.
He proly would not have lost a digit or part thereof (as in a RAS), but he
certainly came close to requiring a lot of stitches, and poss. nerve
damage -- which can be almost as bad as losing a digit.
How does a riving knife work? Never saw one before this.
AFAIK there's no data available from SawStop on the number of false
positives (and, of course there's no data on how many users turn the
bypass control on to be sure to avoid any chance of same when working
with wet wood such as PT).
The best one can tell from the patent is
"In many of the exemplary embodiments and implementations described above
and in the references incorporated herein, detection subsystem 22 relies
on the inherent electrical capacitance and/or resistance of the user's
body to modify the effective capacitance and/or resistance of the
cutting tool or operative structure."
The patent is (as are all well-constructed ones) written to cover not
only the actual "embodiment" but every possible variation of it that the
applicant can manage to stretch the colorful language to cover. In
early interviews it was pretty clear that it is capacitive coupling that
was used at least in the initial product and I presume it is likely
still the same fundamental technology used in the current saws w/ some
improvements owing to the experience factor. It's the same idea as the
"touch switches" on table lamps, etc. -- the body has much higher
capacitance owing to the water content than does dry lumber and if the
blade monitor sees a drop it presumes that's not good and fires.
It's a clever technology and worthwhile--my complaint w/ Gass is his
attempt to now force it on the market to make a bundle by
legislative/mandatory means rather than by winning the competitive
battle in the marketplace.
--
I was going to add that it will be _most_ interesting when the first
failure to actuate when needed occurs and the ensuing lawsuit forces
him/SawStop to rely on the same arguments to try to defend his bottom
line as they used against the present manufacturers of inherently
unsafe... :)
It _will_ happen eventually; no technology is completely failure-proof
either from a simple failure of the mechanics to fire when demanded or
the electrical sensor system fails or whatever.
Or, the doofus operator like the one that got Hitachi(?) who has no
knowledge of the operation and doesn't know the override is on and then
sues because the saw should've known that and not let him...
"dpb" wrote in message
On 12/4/2012 12:33 PM, dpb wrote:
...
I was going to add that it will be _most_ interesting when the first
failure to actuate when needed occurs and the ensuing lawsuit forces
him/SawStop to rely on the same arguments to try to defend his bottom
line as they used against the present manufacturers of inherently
unsafe... :)
It _will_ happen eventually; no technology is completely failure-proof
either from a simple failure of the mechanics to fire when demanded or
the electrical sensor system fails or whatever.
Or, the doofus operator like the one that got Hitachi(?) who has no
knowledge of the operation and doesn't know the override is on and then
sues because the saw should've known that and not let him...
=========================================================================Or the guy that has it turned off because he doesn't want an accidental
trip, hurts himself and then sues, claiming that it was on.
Bear in mind that the override is a one-shot. You have to set it every
time you power up the saw and it resets to the default mode when you
turn off the switch.
On 12/4/2012 12:45 PM, Existential Angst wrote:
...
...
Actually, I have seen a demo of Gass w/ a hotdot on a stick and swinging
it pretty quickly. It didn't get more than a nick that at most a stitch
or two would take care of.
As for the VW, sure--it was nothing but a tin can on wheels then...otoh,
a 1975 Buick weighed probably 25% more than the largest one you could
manage to equip today and that's pretty much true on the overall US
fleet average. Has had to happen because of the EPA fleet-average
mileage rules...
The cost differential on the SawStop is owing imo to brand
identification and uniqueness in the field as well as to the actual
production cost differential between that saw and the same one w/o the
actuator mechanism--that really is a meaningless comparison as there
isn't any such thing as the Sawstop cartridge mechanism must be designed
into the saw from the git-go--it can't be retrofitted into a
conventionally designed/built saw.
Just as PM and Delta get a premium over Jet for only moderately better
performing saws--they get it because of the reputation they've built
over the years (whether it still deserves the same respect is immaterial
as long as they can command the differential it's a real effect).
--
Am I the only one who would never work with the blade that far above the
wood?
I normally have only a quarter to 3/8 inch of the blade above the piece
of wood. (Higher for harder wood)
Gullet should be at the surface cut or just tad proud for
crosscutting/ripping, granted.
As for "never", well, every rule has its exception. If I'm cutting for
a notch, I may well set the blade at its maximum height to have the
least angle possible and thereby the shortest possible undercut on the
back side of the piece...
But, in general, the point is good one...excessive blade exposure is to
be avoided.
--
RE: Subject
The ambulance chasers are beginning to advertise on daytime
TV here in SoCal for tablesaw accident victims.
Like the smell of blood draws some, money attracts the vultures.
Lew
Theoretically, one could get close enough to the blade to trigger it w/o
actually touching it. That scenario is mentioned in the patent
background since the detection circuit is capacitively coupled there
doesn't have to be actual contact if the disturbance of the capacitance
field is sufficient the actuator logic will think "something's bad" and
trigger.
At least initially there was a manual override switch that one could use
to disable the detection circuitry and I presume there still is altho I
haven't searched the current sales lit thoroughly. It was (is) there
for the express purpose of preventing a false positive trip if the saw
were being used for, say, wet PT lumber or some other product that had a
high-enough capacitance to cause actuation. If the operator thinks it
isn't needed for a given cut or forgets to flip the switch, that's a
second category (albeit one could claim that one is operator error only,
not a false positive, still, the effect is the same).
Similar to that is the possibility of an embedded metallic object (a
nail, iow) that happens to also be in contact w/ the table at the time
it's hit by the blade--that will almost certainly trigger it even though
SS says just a nail if not grounded likely won't be large enough to.
There is always then the chance failure--stuff happens; no technology is
perfect. Undoubtedly small, but still has to be finite and positive.
I notice now that SS has a submittal form for "saves" that says if you
ship them the cartridge/blade and they can determine it actually was
flesh that caused the trip they'll provide a replacement cartridge.
That doesn't cover the cost of either repairing an expensive blade or
replacing one, but it is something. Of course, in that case the avoided
cost of the medical bills likely otherwise probably overshadow the
repair costs significantly.
There is no information at all on the SS site on actual statistics of
any value to do any estimation at all of either type of
actuation--needed or false. There _is_ a (to me) blatant use of the
scare stories and a big countdown clock of "time to next saw accident"
that's just tacky, but then that's me...
--
That close would have to be a tiny fraction of an inch,
so close that you're almost touching it. In which case,
I would not call that a false trip because there isn't any
valid reason to be that close to the blade.
On 12/5/2012 7:18 AM, snipped-for-privacy@optonline.net wrote:
...
Well, unless you actually _did_ touch (and teeth, not just the smooth
blade side), there wasn't an actual required need to trip as there was
not any damage inflicted. That's the definition of a false positive.
--
That may be your definition, but it's not mine, nor do I
think it's a reasonable one. Being 1mm away from a
spinning blade tripping it works for me as a valid need
to stop the saw. And from the video, even
when tripped by actual contact, there was no damage
inflicted.
Regardless of what you put on a swirling blade, whether on a table saw,
RAS, mitre saw, etc. there is nothing that can be put on it to prevent
accidents. There will always be some fool who tries to make an
adjustment to the saw with the blade running or some other dumb thing.
Will the SS prevent this person from being damaged when the glove he is
wearing (suggested previously) snags in the saw and causes and accident?
Would the accident then be blamed on the glove and someone initiate a
campaign to use snag less gloves?
In one of these post some one suggested replacing a table saw with a
Circular Saw. Has any body seen someone who is damaged with a circular
saw? They are the most vicious things in existence.
I had my first table saw accident about two weeks ago, because I DID
SOMETHING STUPID. It was not the fault of any design flaw in the saw, it
was plan stupidity on my part. After it happened and I realized the
extent of the damage, my next though was I don't have SS and have to
repair the saw to finish the job. While what I did was stupid, the
damage was minimal BECAUSE when I started, I set the saw up properly.
"Something stupid" is a variations on the hardest words to say in the
any language I MADE A MISTAKE. No one is willing to take the
responsibility for their own actions they always must be a victim of
some one else s mistakes. Every one from obama who is still blaming
President Bush for his failures to the man working in his garden.
This discussion reminds me of a safety manager I knew many years ago.
In the lab we did a lot of work with 2 ml screw top bottles. These were
used in a plastic bag to protect that sample in a Nitrogen atmosphere.
We got a batch of bad bottles that crumbled when you put the top on to
tight.
The safety manager required us to use HEAVY Rubber gloves for protection
from cuts if the bottle broke. The safety equipment prevented us from
doing our job as the gloves made it impossible to handle the tiny
bottles. Is side the Nitrogen bag it was impossible.
From all that I've seen so far, it would. Blade cuts through glove
then touches finger just as it would with no glove. As soon as it
goes through the glove, the saw stops. What do you have to
suggest that it would not prevent an injury with a glove on?
Which is why if a similar feature could be put into a circular
saw it would be a good thing, no?
Most accidents caused by doing something stupid,
being careless, not having your full attention on the job at
hand? That's why we call them accidents, not
"on-purposes". What does that have to do with anything?
This has nothing to do with people not taking responsibility
for their own actions. Let's go where you seem to want to go.
Let's look at conservatives who believe in personal responsibility.
Do you think none of them have
accidents with a table saw because they are perfect, flawless?
MAYBE they have a lower incidence
of accidents than the general population. But suppose it's
25% less accidents, which I think is a reach.
That still leaves a hell of a lot of cut off
fingers, $20,000 hospital bills, etc. Now, if a new safety feature
works, can prevent that at reasonable cost, I think it's
a very good thing. I'd want it in a product I buy and
I'm a conservative.
Nothing I've seen so far suggests the SawStop prevents you
from doing what you want to do with the saw.
It was Keith that dragged Obama blaming Bush and not
accepting responsibility into this, not me. That is what seems
a giant leap to me. And sorry, but his whole post is
in fact based on ideology, which is simply a set of beliefs.
Apparently he believes that accepting personal responsibility
somehow negates the need for safety protection devices.
That doesn't compute in my world and all I did was point
it out.
> If you don't
As I replied to Keith, what does any of that have to do
with the usefulness of SawStop on a table saw? It's not
an issue of personal responsibility. It's an issue of safety
and the fact that accidents happen to everyone.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.