I have been taking a basic wood working at a local community college.

As you would expect, there is a heavy emphasis on safety.

They have a collection of table saws including General, Delta Unisaw
and PM66.

Over the years there have been a few T/S accidents.

Analyzing these accidents revealed the following:

1) The majority of accidents involved the PM66.

2) After shutting off, the PM66 required 20-30 seconds more to come to
a rest than either the General or Unisaw.

Looking at the saw blade, it was very difficult to see if the blade
was still spinning.

You had to literally "feel" the blade still turning by touching the
table.

Those of you who have a PM66 are aware of this phenomena; however, if
you buy a PM66, be aware.

A PM66 is NOT the same as the General or the Unisaw.

BTW: These saws were all equipped with Biesemeyer fences.

Strong like bull, but give me a Unifence anyday.


Lew

On Sat, 7 Aug 2010 19:31:08 -0700, "Lew Hodgett"
wrote:

I have been taking a basic wood working at a local community college.

As you would expect, there is a heavy emphasis on safety.

They have a collection of table saws including General, Delta Unisaw
and PM66.

Over the years there have been a few T/S accidents.

Analyzing these accidents revealed the following:

1) The majority of accidents involved the PM66.

2) After shutting off, the PM66 required 20-30 seconds more to come to
a rest than either the General or Unisaw.

Looking at the saw blade, it was very difficult to see if the blade
was still spinning.

The only time I've ever come close to getting bitten by my Unisaw was exactly
this. A blade brake would be a great addition to any table saw.

You had to literally "feel" the blade still turning by touching the
table.

Those of you who have a PM66 are aware of this phenomena; however, if
you buy a PM66, be aware.

A PM66 is NOT the same as the General or the Unisaw.

BTW: These saws were all equipped with Biesemeyer fences.

Strong like bull, but give me a Unifence anyday.

Never used a Unifence, so can't say whether I'd like it better or not.
Why?

wrote in message
...
On Sat, 7 Aug 2010 19:31:08 -0700, "Lew Hodgett"
wrote:

I have been taking a basic wood working at a local community college.

As you would expect, there is a heavy emphasis on safety.

They have a collection of table saws including General, Delta Unisaw
and PM66.

Over the years there have been a few T/S accidents.

Analyzing these accidents revealed the following:

1) The majority of accidents involved the PM66.

2) After shutting off, the PM66 required 20-30 seconds more to come to
a rest than either the General or Unisaw.

Looking at the saw blade, it was very difficult to see if the blade
was still spinning.

The only time I've ever come close to getting bitten by my Unisaw was
exactly
this. A blade brake would be a great addition to any table saw.

You had to literally "feel" the blade still turning by touching the
table.

Those of you who have a PM66 are aware of this phenomena; however, if
you buy a PM66, be aware.

A PM66 is NOT the same as the General or the Unisaw.

BTW: These saws were all equipped with Biesemeyer fences.

Strong like bull, but give me a Unifence anyday.

Never used a Unifence, so can't say whether I'd like it better or not.
Why?

Strange, I had a PM66 and didn't feel it took that long to coast down. I'm
not disagreeing- just commenting. It sure was a great saw and once adjusted
with the TS Aligner, it stayed that way.

Nonny

zzzzzzzzzz wrote:
On Sat, 7 Aug 2010 19:31:08 -0700, "Lew Hodgett"
wrote:

I have been taking a basic wood working at a local community college.

As you would expect, there is a heavy emphasis on safety.

They have a collection of table saws including General, Delta Unisaw
and PM66.

Over the years there have been a few T/S accidents.

Analyzing these accidents revealed the following:

1) The majority of accidents involved the PM66.

2) After shutting off, the PM66 required 20-30 seconds more to come
to a rest than either the General or Unisaw.

Looking at the saw blade, it was very difficult to see if the blade
was still spinning.

The only time I've ever come close to getting bitten by my Unisaw was
exactly this. A blade brake would be a great addition to any table
saw.


Some years ago, the federal government, in its infinite wisdom, and all the
while thinking of the children, mandated that washing machines come to a
complete stop in just a few seconds (like three).

It shouldn't be hard to transfer that technology to table saws.

"HeyBub" wrote

Some years ago, the federal government, in its infinite wisdom, and all
the while thinking of the children, mandated that washing machines come to
a complete stop in just a few seconds (like three).

It shouldn't be hard to transfer that technology to table saws.


They have. Toss a dirty sock into the blade and it stops faster than a
washing machine.

Toss a dirty sock into the blade and it stops faster than a
washing machine.

How do you know this? LOL.

Sonny

"Sonny" wrote in message
...
Toss a dirty sock into the blade and it stops faster than a
washing machine.

How do you know this? LOL.

Sonny

Sorry, that is confidential information by the R & D department.

On Sat, 7 Aug 2010 23:34:55 -0400, "Ed Pawlowski" wrote:


"HeyBub" wrote

Some years ago, the federal government, in its infinite wisdom, and all
the while thinking of the children, mandated that washing machines come to
a complete stop in just a few seconds (like three).

It shouldn't be hard to transfer that technology to table saws.


They have. Toss a dirty sock into the blade and it stops faster than a
washing machine.

So *that's* what happens to the missing socks.

"Ed Pawlowski" wrote in message
...

"HeyBub" wrote

Some years ago, the federal government, in its infinite wisdom, and all
the while thinking of the children, mandated that washing machines come
to a complete stop in just a few seconds (like three).

It shouldn't be hard to transfer that technology to table saws.


They have. Toss a dirty sock into the blade and it stops faster than a
washing machine.


Dont count on it. I experimented with this several years ago using a
canvas/leather work glove. The blade left a clean kerf. There was the
notion that if you used gloves with a TS the blade could catch the glove and
pull your hand in. I do not recoment using a glove BTY but cloth and
leather cut much more easily than wood.

"HeyBub" wrote in message
m...
zzzzzzzzzz wrote:
On Sat, 7 Aug 2010 19:31:08 -0700, "Lew Hodgett"
wrote:

I have been taking a basic wood working at a local community college.

As you would expect, there is a heavy emphasis on safety.

They have a collection of table saws including General, Delta Unisaw
and PM66.

Over the years there have been a few T/S accidents.

Analyzing these accidents revealed the following:

1) The majority of accidents involved the PM66.

2) After shutting off, the PM66 required 20-30 seconds more to come
to a rest than either the General or Unisaw.

Looking at the saw blade, it was very difficult to see if the blade
was still spinning.

The only time I've ever come close to getting bitten by my Unisaw was
exactly this. A blade brake would be a great addition to any table
saw.


Some years ago, the federal government, in its infinite wisdom, and all
the while thinking of the children, mandated that washing machines come to
a complete stop in just a few seconds (like three).

It shouldn't be hard to transfer that technology to table saws.


My Hitachi has a brake. Last shop I worked in (that I used a tablesaw),
there was a rule that when you turned it off, you cranked the blade down
below table height. Not always possible but could do so most of the time.

On Sat, 7 Aug 2010 21:35:10 -0700, "CW" wrote:


"HeyBub" wrote in message
om...
zzzzzzzzzz wrote:
On Sat, 7 Aug 2010 19:31:08 -0700, "Lew Hodgett"
wrote:

I have been taking a basic wood working at a local community college.

As you would expect, there is a heavy emphasis on safety.

They have a collection of table saws including General, Delta Unisaw
and PM66.

Over the years there have been a few T/S accidents.

Analyzing these accidents revealed the following:

1) The majority of accidents involved the PM66.

2) After shutting off, the PM66 required 20-30 seconds more to come
to a rest than either the General or Unisaw.

Looking at the saw blade, it was very difficult to see if the blade
was still spinning.

The only time I've ever come close to getting bitten by my Unisaw was
exactly this. A blade brake would be a great addition to any table
saw.


Some years ago, the federal government, in its infinite wisdom, and all
the while thinking of the children, mandated that washing machines come to
a complete stop in just a few seconds (like three).

It shouldn't be hard to transfer that technology to table saws.


My Hitachi has a brake. Last shop I worked in (that I used a tablesaw),
there was a rule that when you turned it off, you cranked the blade down
below table height. Not always possible but could do so most of the time.

Musta been one PITA for dado cuts. ;-)

wrote in message
...
Musta been one PITA for dado cuts. ;-)


As I said, not always possible though I never had a need for a dado blade. I
was making vacuum molds, not furniture.

On 8/7/2010 11:22 PM, HeyBub wrote:
zzzzzzzzzz wrote:
On Sat, 7 Aug 2010 19:31:08 -0700, "Lew Hodgett"
wrote:

I have been taking a basic wood working at a local community college.

As you would expect, there is a heavy emphasis on safety.

They have a collection of table saws including General, Delta Unisaw
and PM66.

Over the years there have been a few T/S accidents.

Analyzing these accidents revealed the following:

1) The majority of accidents involved the PM66.

2) After shutting off, the PM66 required 20-30 seconds more to come
to a rest than either the General or Unisaw.

Looking at the saw blade, it was very difficult to see if the blade
was still spinning.

The only time I've ever come close to getting bitten by my Unisaw was
exactly this. A blade brake would be a great addition to any table
saw.


Some years ago, the federal government, in its infinite wisdom, and all the
while thinking of the children, mandated that washing machines come to a
complete stop in just a few seconds (like three).

It shouldn't be hard to transfer that technology to table saws.

They did in the EU and then found out that the mandated brake wouldn't
stop a dado in the specified time, so their solution was to require that
the shaft be too short to accommodate a dado. Be careful what you wish for.

"HeyBub" wrote in message
m...



Some years ago, the federal government, in its infinite wisdom, and all
the while thinking of the children, mandated that washing machines come to
a complete stop in just a few seconds (like three).

It shouldn't be hard to transfer that technology to table saws.


Sawstop

Leon wrote:
"HeyBub" wrote in message
m...



Some years ago, the federal government, in its infinite wisdom, and
all the while thinking of the children, mandated that washing
machines come to a complete stop in just a few seconds (like three).

It shouldn't be hard to transfer that technology to table saws.


Sawstop

Nah - don't need sawstop for this need Leon. A simple brake is all that is
necessary. With all of the chop saws that come with brakes today, it really
should be no big deal for a table saw to have the same capability - it's
been around forever.

--

-Mike-

Only takes a simple SPST switch in the power switch and a resistor to absorb
the energy and help stop the switch contacts from burning out so fast.
Syncro motors genertae enough induced EMF to make the stop suprisingly,
quite dramatically. Many chop saws attempt to do this without the energy
absorption ballast resistor and the switch burns out in a few months.


"Mike Marlow" wrote in message
...
Nah - don't need sawstop for this need Leon. A simple brake is all that is
necessary. With all of the chop saws that come with brakes today, it really
should be no big deal for a table saw to have the same capability - it's
been around forever.

--

-Mike-




Leon wrote:
"HeyBub" wrote in message
m...



Some years ago, the federal government, in its infinite wisdom, and
all the while thinking of the children, mandated that washing
machines come to a complete stop in just a few seconds (like three).

It shouldn't be hard to transfer that technology to table saws.


Sawstop

In article ,
Mike Marlow wrote:
...snipped...
Nah - don't need sawstop for this need Leon. A simple brake is all that is
necessary. With all of the chop saws that come with brakes today, it really
should be no big deal for a table saw to have the same capability - it's
been around forever.

--

I agree with that: I've seen brake setups on industrial machinery powered
by 150 HP motors, geared down to about 30 RPM turning a roller that weighed
a few tons, that could stop the roller in less than a 1/4 turn. I don't see
why any sacrificial parts are necessary for a saw to do what the sawstop
does. If Delta, Jet, etc. wanted to spend a little R&D money, they
could build a safer saw that was _better_ than sawstop.



--
Better to be stuck up in a tree than tied to one.

Larry Wasserman - Baltimore Maryland - lwasserm(a)sdf. lonestar.org

"Mike Marlow" wrote in message
...
Leon wrote:
"HeyBub" wrote in message
m...



Some years ago, the federal government, in its infinite wisdom, and
all the while thinking of the children, mandated that washing
machines come to a complete stop in just a few seconds (like three).

It shouldn't be hard to transfer that technology to table saws.


Sawstop

Nah - don't need sawstop for this need Leon. A simple brake is all that
is necessary. With all of the chop saws that come with brakes today, it
really should be no big deal for a table saw to have the same capability -
it's been around forever.

Granted but the reason to stop the blade is for safety and that technology
is already around on several levels of effectiveness.

On Aug 7, 11:22*pm, "HeyBub" wrote:
wrote:
On Sat, 7 Aug 2010 19:31:08 -0700, "Lew Hodgett"
wrote:

I have been taking a basic wood working at a local community college.

As you would expect, there is a heavy emphasis on safety.

They have a collection of table saws including General, Delta Unisaw
and PM66.

Over the years there have been a few T/S accidents.

Analyzing these accidents revealed the following:

1) The majority of accidents involved the PM66.

2) After shutting off, the PM66 required 20-30 seconds more to come
to a rest than either the General or Unisaw.

Looking at the saw blade, it was very difficult to see if the blade
was still spinning.

The only time I've ever come close to getting bitten by my Unisaw was
exactly this. *A blade brake would be a great addition to any table
saw.

Some years ago, the federal government, in its infinite wisdom, and all the
while thinking of the children, mandated that washing machines come to a
complete stop in just a few seconds (like three).

It shouldn't be hard to transfer that technology to table saws.- Hide quoted text -

- Show quoted text -

Electric brake -- short out the supply wires after cutting the power,
and the motor forces itself to stop.

This is better with some resistance to absorb the energy. Without it the
switch contacts usually burn off, quickly.


"Father Haskell" wrote in message
news:02510f27-22e4-4de7-afca-Electric brake -- short out the supply wires
after cutting the power,
and the motor forces itself to stop.

"Father Haskell" wrote

Electric brake -- short out the supply wires after cutting the power,
and the motor forces itself to stop.

For an almost instant stop, I gather that something called DC injection is
required and this requires a special and expensive motor.

Jeff

--
Jeff Gorman, West Yorkshire, UK
email : Username is amgron
ISP is clara.co.uk
www.amgron.clara.net

Not true.

I worked with many different dynamic and mechanical braking systems,
including DC Injection braking and none were any special motors. OTOH these
were industrial applications using larger HP units.

Geeeeez. My cheap $189 slide saw has dynamic braking on it and I doubt it is
any special motor. The blade had to worth half the price. It also has a
delay circuit that doesn't react immediately.


"Jeff Gorman" wrote in message
...
For an almost instant stop, I gather that something called DC injection is
required and this requires a special and expensive motor.

Jeff



"Father Haskell" wrote
Electric brake -- short out the supply wires after cutting the power,
and the motor forces itself to stop.

On Aug 7, 9:31*pm, "Lew Hodgett" wrote:
I have been taking a basic wood working at a local community college.


2) After shutting off, the PM66 required 20-30 seconds more to come to
a rest than either the General or Unisaw.

That is what got me about 10 years ago and it wasn't a PM66. If was
an old Craftsman contractor's saw that I used to own. Shut the switch
of and started to walk away with a handful of small spaces I had just
cut off. I looked over my shoulder and noticed one on the table next
to be blade. In a brain-dead moment I over-reached the blade and got
nicked, to the bone, on a fingertip. Even the clunky old Craftsman
was still spinning down.

Stupid but it sure taught a lesson.

RonB

"Lew Hodgett" wrote in message
...
I have been taking a basic wood working at a local community college.

As you would expect, there is a heavy emphasis on safety.

They have a collection of table saws including General, Delta Unisaw and
PM66.

Over the years there have been a few T/S accidents.

Analyzing these accidents revealed the following:

1) The majority of accidents involved the PM66.

2) After shutting off, the PM66 required 20-30 seconds more to come to a
rest than either the General or Unisaw.

WOW! That is an exceptionally long time. I wonder if it is because of the
type belt that is used, not the typical v-belt rather the less resistant
serpentine belts.


Looking at the saw blade, it was very difficult to see if the blade was
still spinning.

That may be more to do with lighting. I recall 40 years ago my shop teacher
warning to be careful around the blade during spin down as it went and out
of phase with the floresent lighting. Basically working like an automotive
timing light. It did indeed appear to be paused a few times when shud town.
As it would slow to near in phase timing the blade would appear to go
backwards, stop, spin forward, etc. If the blade takes an exceptionally
long time to come to a stop the "in phase" periods with the lighting would
last longer.