Ping Leon: Design Q on SawStop

There seems to be two mechanical strategies at work in the SawStop, of translation, and of rotation, ie, retracting the blade, and stopping the rotation.
It seems to me one would be sufficient, with retraction having the advantage of being non-destructive. Not sure if the blade is direct drive or belt drive, but if it was belt drive, the retraction could all the more rapid, since you would not have to retract the mass of a relatively heavy motor. In fact, if designed properly, you could proly have only the blade and its bearing retract, along grooved guides of some sort, allowing for a very rapid acceleration from whatever force is applied -- presumably springs? But could also be pneumatic or hydraulic, or solenoidal.
Unless the deceleration of rotation is just an inherently faster process than the retraction process. But, from what I see, it seems the retraction is occurring FIRST, anyway, to initiate the destructive crash, so mebbe the rotational issue is irrelevant??
Now, if rotation is still an issue, wouldn't a caliper/rotor brake type deal be as fast as his collision process, AND be non-destructive? Mebbe multiple calipers.
Oh, oh, but then he wouldn't be able to sell new crumple ditties at $70/pop.....
Mebbe you could run this by (G)ass, ask him to send me $5 if he likes the idears. Or mebbe just invite me to one of them 'spensive luncheons, where he's twisting CONgress's arms on safety'n'shit, you know, for all the li'l children....
--
EA




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In the videos I've seen the blade is fully stopped, while the retraction is only partial, more like the retraction has only started. And I think one problem with relying only on retraction would be that it's not going to be fast enough to get all or enough of the blade out of the way. You could do the math and find the force necessary to move a given mass several inches in 1ms.
A side question is why have the retraction at all. I guess if you're flopping a whole arm down on the saw, it would prevent injury from just hitting a stopped blade.

It would have to be one hell of a caliper brake to stop that spinning saw in 1ms. With the way it's implemented now, at first contact of the jamb the saw is stopped dead.

You really think he didn't think of a simple brake, like they have on say lawn mowers, first?
 Or mebbe just invite me to one of them 'spensive luncheons, where

Or better yet that anyone involved in this is interested in answering your questions, given all the insults and names you've called them?
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On 12/8/2012 9:56 AM, snipped-for-privacy@optonline.net wrote:

Maybe if you two watched the video you'd understand. The blade is stopped, and that is actually part of the retraction mechanism. The inertia is dissipated by retracting. The retracting saves the finger as well since it is pulling away from the finger.
The design as it stands is very good, your ideas are not. BTW this is a top notch saw, so no it is not direct drive. The workmanship on all of these saws exceeds what we now currently have from the standard non-euro options.
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"tiredofspam" <nospam.nospam.com> wrote in message wrote:

Really? And you know all this..... how??
--
EA




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On Dec 8, 10:35 am, tiredofspam <nospam.nospam.com> wrote:

I did watch the video. Nothing in the video shows exactly how the blade retracts, what it's attached to beneath the saw, etc. And there isn't just one video, so how would you know what videos anyone did or did not see.

OK, using the momentum of the saw to retract the blade makes sense. Is that all that causes the retraction or is there something else, eg spring involved?

I think you're confused. You replied to my post. I did not propose changing the SawStop. I'm fine with it. It was EA that was proposing the new ideas and simply pointed out some of the obvious issues.
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On 12/8/2012 11:03 AM, snipped-for-privacy@optonline.net wrote:

They actually have videos explaining the retraction and why it is done and how it is done (high level)

No I'm not confused. EA was proposing changing it, I am aware of that. But you questioned the need to retract. That is also in one of the videos. You can't stop something that quick, w/o having the inertia go somewhere or you will stress the machine. This serves 2 purposes.
This is a very good design. How do I know, well, as someone who went to school for engineering, but wound up in IT, I think I know a good design when I see one. Number 2, I have seen the videos, I have touched the machine on more than a few occasions. I would buy that machine for my next TS if and when I need one.
I have always been involved with one form of building whether it be wood , mechanical (race cars), machines ... It's what I am good at, and what I enjoy doing. You get to know BS from good stuff. You get to know the stuff where they missed the mark. How many products solve a problem that doesn't exist.
This saw is well designed, well made, and most people have a gripe about GASS. I have no gripe about him, I am concentrating on his saw. It's superior to the others because he has included a Riving Knife, a heavy cabinet. A beautiful trunion. a flawless top, a fence that a tank couldn't move. I put 200 lbs of force into it sideways and it did not deflect... I am very impressed with what went into this saw design wise.
The price is high, but you are getting a better saw even w/o the stop mechanism. 12 years ago a Unisaw could be had for just under 1200... now forget about it. What are you getting for that money? Not much. Same with PM and Jet
Look at the machine work on the SS... its beautiful. So not only engineered well, but it is built well.
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"tiredofspam" <nospam.nospam.com> wrote in message wrote:

Gimme a fukn break already....
Fuck (G)ass.
--
EA





Number 2, I have seen the videos, I have touched the
> machine on more than a few occasions. I would buy that machine for my
  Click to see the full signature.
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On Sat, 8 Dec 2012 12:13:06 -0500, "Existential Angst"

You probably would too.
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He'da wished he'da built one of his 'Stop ditties for my dick....
--
EA



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Alls I know is, having cut my finger nearly in half (still got it, though) is that I'll be buying a Sawstop saw as soon as I get a 240V circuit added to my garage. The electrical guy comes next Tuesday.
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On 12/8/2012 11:36 AM, scritch wrote:

There are those the believe that they are too careful and or smart to benefit from a SawStop and will refuse to get one in spite of Gass.
There are those that are careful and smart that have had a serious injury and will one day buy a SawStop as they now are even more smarter and more careful because they now have first hand knowledge of how the unforeseen can get you.
I cut half my thumb off 23 years ago, unfortunately long before the SawStop became a reality.
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Then there are those who are careful and smart, yet have still managed to have some kind of (albeit minor, in my case) injury, and would love to have a gadget like this....but refuse to knuckle under to Gass' thug-like tactics & are waiting patiently for a competitor's product. ;)
-Kevin in Indy To reply, remove (+spamproof+) from address........
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On 12/8/2012 6:47 PM, vonKevin wrote:

Those people are the ones that will cut off their nose to spite their faces, can't see the forest for the trees, know better but will continue to take risks.
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"tiredofspam" <nospam.nospam.com> wrote in message wrote:

I've seen the actual patent, IIRC...
I can't remember the details about the sensing mechanism...but...
A block of aluminum acts as a brake, effectively stopping the blade dead in it's tracks by more or less directly engaging six teeth or more all at the same time (depending on blade pitch) which equates to maybe 10 degrees of rotation...
--if you do the math, what you'll find is that you'd have to be moving your finger into the blade at speeds that are simply not humanly possible in order to do anything more than to draw a very slight amount of blood.
Kind of like the bullet that you never heard...

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On Sun, 9 Dec 2012 00:03:49 -0800, "Lew Hodgett"

So, what now? Total senility in operation?
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On 12/9/2012 2:44 AM, Dave wrote:

His current responses are much better than the OT gas pricing.
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