To Close for Comfort

The Sawstop doesn't guarantee that no injury will happen. They do, however, have a pretty good argument for reducing the severity of injuries. Slamming your palm as hard and fast as you can on the spinning blade of a regular saw is surely gonna do more damage than slamming your palm on a Sawstop blade. A row of stitches is preferable to a stump, I think.

I have explained to anyone who usually would be bold enough to walk into my garage, to speak with me. Do not walk in, stand a few feet from the opening and wait till I notice you. Or wait till Im not near any machine while operating it.
My wife fully complies, and my buddy who stops by now and then, he will usually sit in my driveway in his van until I wave to him.

But now, Im going to build a sign and stand it 5 feet in front of my garage when Im working there warning anyone not to walk further until I invite them.

What I used to have the kids do, and my wife still does, is to flash the lights to get my attention. I always wear good hearing protection and can hardly hear normal voices with the ear muffs on.

Glad nothing serious happened, it gives me the creeps to think that you could just have place your hand on top of the spinning blade.

Kerry Burton said:

OK, let's see. The specs say that the blade is stopped within 5 milliseconds of contact with flesh.

The 10" saw blade is spinning at what ... 3450 RPM? That's

3450 x 10" diameter x 3.14 (pi) = 108,330 inches per minute at the tooth tips
108,330 / 60 = 1806 inches per second​

In 5 milliseconds the blade would travel

1806 inches/sec * 5 msec * (1 sec/1000 msec) = 9030 / 1000 = 9.03 inches​

Did I do the math right?

Now the question is ... what motion should we assume for the flesh during those 5 milliseconds?

Click to expand...

If you are holding on to the piece, 9 inches. That is all the distance from the saw blade to the back of the saw, so I don't know, it might not be fast enough. I have no idea, but it would be easy to set up a test. It happens really fast, I can tell you that. It was instantanious from the time I was tapped on the shoulder to the time I had one less finger. It was a 12" saw with a 71/2 hp motor, running a 10" dado. I had made over 50 of these cribs using the same jig, the jig was fine under normal circumstances. Ironically this was a crib I was making for my 1st grandchild.

Kerry Burton said:

The specs say that the blade is stopped within 5 milliseconds of contact with flesh.
[...]
In 5 milliseconds the blade would travel

9.03 inches​

[...]
Now the question is ... what motion should we assume for the flesh during those 5 milliseconds?

Click to expand...

Larry Edgerton said:

If you are holding on to the piece, 9 inches. That is all the distance from the saw blade to the back of the saw, so I don't know, it might not be fast enough.

Click to expand...

= = = = = = = = = = = = = = =

Hmmm. Perhaps the 9 inches of travel for the saw teeth (around that fixed, 10" diameter circle) is irrelevant. The real question is how long does it take a 3/4" thick finger to cross that circle? If it's less than 5 msec, then "severed finger" will be the natural result.

Some more math, to determine how fast your hand would have to be moving ... assuming the direction of travel is perpendicular to the tooth circle (heading straight toward the saw arbor):
I don't know what normal feed rates are ... 1 foot/sec? Less than that?

I don't have a clear picture regarding the 9 inches you mentioned. Can you elaborate?