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J. Clarke[_2_]

In article ,
says...

On Fri, 15 Oct 2010 09:32:43 -0400, "J. Clarke"
wrote:

In article ,
says...

On Thu, 14 Oct 2010 16:22:22 -0500, Steve Turner
wrote:

On 10/14/2010 2:52 PM, wrote:
On Thu, 14 Oct 2010 09:27:45 -0400, "Mike Marlow"
wrote:

Larry Jaques wrote:
On Thu, 14 Oct 2010 08:50:21 -0400, "Mike Marlow"
wrote:

As a guy who has done all of his own vehicle maintenance for 40
years now, I have to ask what you observed in your experiences, that
causes you to make this statement? I don't know if the brake
caliper idea is the most elegant solution, but I sure can't see
anything in what you are saying that would suggest it is not a
workable solution.

Suitable placement of an air nozzle tube to clear the caliper frame
every hour or so would go far into making this device work for more
than an hour. You'd have to keep the sawdust from piercing the seals
and/or building up on the frame

Not at all Larry, if you consider what a normal brake caliper in an
automobile is subject to. In comparison, the environment inside a table saw
would be a walk in the part of a caliper.

You get a splinter of oak thrown at a rubber caliper boot at 18000
feet per minute (almost 205MPH) a few times and expect the boot to
survive?. For the brake to see the same rotational RPM on a car with
24" diameter tires (pretty standard today) you would need to drive
over 250 MPH. Closer to 260MPH if the saw runs 3650 RPM.

A 10" saw runs closer to 5200 RPM - so 370 MPH.

Ever heard of "mass"? By your logic, my Dremel tool running at 30,000 RPM
would be even more impossible to stop.

No, I said nothing of the sort. I didn't even say anything about it
being hard to stop. I was comaring the speed at which particals might
possibly hit the boot on the lincoln caliper some dufus was talking
about mounting to the table saw to stop the blade, The speed at which
a sliver could be flung at that boot from a typical table saw blade
would require the above mentioned speeds with the caliper on a car -
assuming the bit was picked up from the road or thrown from the
circumference of the tire.
Also, the caliper is actually pretty well protected mounted as it is
virtually inside the wheel - with the caliper boot protected between
the pad and tha caliper frame, and usually behind a splash shield as
well.

Then start sawing oak, and leaving the VERY CORROSIVE sawdust caked
onto every surface of the caliper.

Geez Chicken Little, how many mountains are you going to make out of molehills
on this topic? Just about every point you've tried to make has had the air of
doom, disaster, and failure. This ain't that friggin' difficult, Penelope.

Nobody said it was difficult. Just saying the brake from the old
lincoln is NOT going to be anywhere close to an effective solution.
So many guys on the Wreck just make things WAY too complicated.

You want a convenience brake on an AC table saw? DC injection braking
is as simple as it gets and can be done by a reasonably adept
scrounger for less than $25 in less than an hour, with NO
modifications to the physical part of the saw. Just grabbing a few
parts out of my scrap bin I could have it working on a saw in less
than half an hour with no cash outlay at all. Not fully automated -
but hit the stop button or turn off the power and press a pushbutton
untill the blade stops (about 2 seconds) using nothing more than an
old PC power supply and a pushbutton switch. To make it a littlemore
foolproof the power switch would need to be replaces with a SPDT or
DPDT switch or augmented by a relay to prevent injecting the DC while
the AC was still connected.

But if I have to push a button to stop the blade I may as well just
shove a pushstick into the side of it.

Which is why using the DPDT switch makes it foolproof. and simple
circuitry can handle the injection current timing.

So where can I buy a DPDT switch with a big red "off" button that I can
hit with my knee?