Dual fences?

Sat, Feb 2, 2008, 2:41pm [email protected]
(Jim=A0Behning) doth sayeth:
<snip> You now have two pieces of wood that you are trying to safely
pass by the saw blade. <snip>

I've read, and re-read, that, and still can't figure out what
you're tryping to say. You've got ONE piece of wood, with two fences
or one, until the blade passes thru the last of the wood. If you're
using a push block, either way, I see no problem. O a push stick.
Either way, if the board is sufficiently long, it will tip up away from
the blade. Ahhhh, you guys argue about it, I don't really care. If I
felt it would be useful, I would have qualms about using two fences.
But, I don't, so I don't., too many other options to choose from that I
would prefer to use.



JOAT - who does not welcome thread question e-mails..

10 Out Of 10 Terrorists Prefer Hillary For President - Bumper Sticker

I don't have a problem with a woman president - except for Hillary.

"Bonehenge (B A R R Y)" <[email protected]> wrote

You need three
> conditions for serious kickback:
>
> 1. - Rising Teeth
> 2. - A fence to trap the work against, to provide traction
> 3. - Enough slop to allow the wood to rotate against the rising teeth,
> or a board that pinches shut after being cut.
>
> Ripping a board that's short and wide, or using a miter gauge and rip
> fence together (without extra room to the side of the blade) can also
> get ugly in a hurry.
>
> You can prevent kickback by eliminating at least one of the conditions
> above. For example, a splitter prevents the cut wood from pinching or
> being grabbed by the rising teeth. A properly adjusted fence
> eliminates the slop.

Might one supplement this excellent advice with the suggestion that using a
short ripping fence, ie one that guides the wood no further than the gullets
of the teeth, is also a good precaution against kickback.

Jeff

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

On Feb 2, 9:09 pm, BoyntonStu <[email protected]> wrote:
> On Feb 2, 8:03 pm, [email protected] (J T) wrote:
>
>
>
> > Sat, Feb 2, 2008, 2:41pm [email protected]
> > (Jim Behning) doth posteth:
> > Have you ever been shot in the belly by a piece of wood that the saw
> > kicked back? Huge risk of increased kickback if you try that. You now
> > have two pieces of wood that you are trying to safely pass by the saw
> > blade. With just one fence the waste can lay on the table or fall off
> > the table with marginal risk of getting tossed back by the blade.
> > If your wood is not parallel you have chances for even more adventures
> > in kickback and binding.
>
> > If you stand out of line of the blade you won't get hit by
> > kickback. When I was in high school shop class the teacher showed use
> > what kickback was. He then told us not to do that. And I never hav
>
> > I don't see a problem with two fences, if they are parallel to each
> > other and the blade. I also don't see the need.
>
> > JOAT - who does not welcome thread question e-mails..
>
> > 10 Out Of 10 Terrorists Prefer Hillary For President - Bumper Sticker
>
> > I don't have a problem with a woman president - except for Hillary.
>
> Here's another idea based on your post.
>
> I have a sled.
>
> Using clamps the board is fixed.
>
> The sled has a stop.
>
> Why not stand on the other side and pull the sled instead of pushing
> it?
>
> The 'kickback' would go away from you.
>
> Completely safe?

You want to be reaching across the blade?

Sat, Feb 2, 2008, 2:41pm [email protected]
(Jim=A0Behning) doth posteth:
Have you ever been shot in the belly by a piece of wood that the saw
kicked back? Huge risk of increased kickback if you try that. You now
have two pieces of wood that you are trying to safely pass by the saw
blade. With just one fence the waste can lay on the table or fall off
the table with marginal risk of getting tossed back by the blade.
If your wood is not parallel you have chances for even more adventures
in kickback and binding.

If you stand out of line of the blade you won't get hit by
kickback. When I was in high school shop class the teacher showed use
what kickback was. He then told us not to do that. And I never hav

I don't see a problem with two fences, if they are parallel to each
other and the blade. I also don't see the need.



JOAT - who does not welcome thread question e-mails..

10 Out Of 10 Terrorists Prefer Hillary For President - Bumper Sticker

I don't have a problem with a woman president - except for Hillary.

On Feb 2, 8:03 pm, [email protected] (J T) wrote:
> Sat, Feb 2, 2008, 2:41pm [email protected]
> (Jim Behning) doth posteth:
> Have you ever been shot in the belly by a piece of wood that the saw
> kicked back? Huge risk of increased kickback if you try that. You now
> have two pieces of wood that you are trying to safely pass by the saw
> blade. With just one fence the waste can lay on the table or fall off
> the table with marginal risk of getting tossed back by the blade.
> If your wood is not parallel you have chances for even more adventures
> in kickback and binding.
>
> If you stand out of line of the blade you won't get hit by
> kickback. When I was in high school shop class the teacher showed use
> what kickback was. He then told us not to do that. And I never hav
>
> I don't see a problem with two fences, if they are parallel to each
> other and the blade. I also don't see the need.
>
> JOAT - who does not welcome thread question e-mails..
>
> 10 Out Of 10 Terrorists Prefer Hillary For President - Bumper Sticker
>
> I don't have a problem with a woman president - except for Hillary.

Here's another idea based on your post.

I have a sled.

Using clamps the board is fixed.

The sled has a stop.

Why not stand on the other side and pull the sled instead of pushing
it?


The 'kickback' would go away from you.


Completely safe?

On Sun, 03 Feb 2008 15:14:09 -0500, Tanus <[email protected]> wrote:

>
>I like that explanation, and there's
>another factor to be considered. A
>kickback "away from you" is still a
>kickback. Wood flies.
>

Not with much force, unless it's a tiny offcut.

It's the "trap" that creates the traction on any decent sized part.

On Sun, 3 Feb 2008 10:17:05 -0800 (PST), BoyntonStu <[email protected]>
wrote:


>Conclusion: Sliding tables are inherently safer than bare table saws.
>

Good!

> Use a hold down next to the fence as close to the
>lifting blade as possible.

Good! They call these "feather boards".

> Install a splitter if possible (harder on a slide
>table)

Not necessary with a sliding table, but big time necessary when
ripping, unless your ripping with a taper sled.

> A second fence not even touching the board

If it's not touching the board, why is it there? When it DOES touch,
it's all over.

On Feb 4, 8:46 am, BoyntonStu <[email protected]> wrote:
> On Feb 3, 7:42 pm, "Bonehenge (B A R R Y)"
>
> <[email protected]> wrote:
> > On Sun, 3 Feb 2008 15:33:55 -0800 (PST), Father Haskell
>
> > <[email protected]> wrote:
>
> > >You want to be reaching across the blade?
>
> > BINGO!
>
> No.
>
> You are standing on the teeth rising side of the table saw.

The front of the blade nips you. The heel pulls you in
and shreds you.

> Your sled has a handle between you and the blade.

Keep your hands away from the blade.

> The sled has a stop and you cannot pull the sled off the table.
>
> The hold down(s) eliminate the need for hands anywhere near the blade.

Birch ply has an excellent low traction surface if sanded to 220 and
finished with two coats of wipe on poly. Workpieces are easily
slid into place, and stay in place under hand pressure.

> You pull the sled towards you.

Reaching across the blade.

Don't force us to repost that bandsaw jpg.

> Any flying wood goes away from you.
>
> The sled could also have a backstop to trap anything flying its way.
>
> How is it possible for anyone or anything to be hit?

The only thing to worry about being his is you. Stand
to one side of the blade.

On Feb 3, 9:39 am, "Bonehenge (B A R R Y)"
<[email protected]> wrote:
> On Sat, 2 Feb 2008 18:09:42 -0800 (PST), BoyntonStu <[email protected]>
> wrote:
>
> >I have a sled.
>
> >Using clamps the board is fixed.
>
> >The sled has a stop.
>
> >Why not stand on the other side and pull the sled instead of pushing
> >it?
>
> >The 'kickback' would go away from you.
>
> >Completely safe?
>
> Unsafe for other reasons, such as the mechanics of reaching long
> distances, but safe for other reasons I'll mention below.
>
> The bottom line: You don't understand kickback. The key to safely
> and successfully using machine tools is a solid understanding of the
> physics involved in each operation and using them to your advantage.
> Fear based "safety" workarounds usually have unintended side effects,
> at the minimum destroying accuracy or speed of work.
>
> Boards clamped to sleds are not the same as boards trapped between a
> fence and the rising back teeth of a saw blade. You need three
> conditions for serious kickback:
>
> 1. - Rising Teeth
> 2. - A fence to trap the work against, to provide traction
> 3. - Enough slop to allow the wood to rotate against the rising teeth,
> or a board that pinches shut after being cut.
>
> Ripping a board that's short and wide, or using a miter gauge and rip
> fence together (without extra room to the side of the blade) can also
> get ugly in a hurry.
>
> You can prevent kickback by eliminating at least one of the conditions
> above. For example, a splitter prevents the cut wood from pinching or
> being grabbed by the rising teeth. A properly adjusted fence
> eliminates the slop. Without traction (as on the clamped sled or the
> offcut side of a rip), the possible force of kickback is greatly
> reduced.
>
> Here's a decent demo that looks like it's filmed in a school shop:
> <http://www.metacafe.com/watch/910584/table_saw_kickback_demonstration/>
>
> Some teachers will demonstrate the same thing using foam.

Good video.

Comments:

1> The kickback was away from the fence and it flew in rotation like
a frisbee..

2> If another fence was on the other side of the board, how could it
fly off the table?

3> A hold down near the fence would prevent lift.

4> A slide table push fence would not allow the board held against
it to frisbee rotate.

Conclusion: Sliding tables are inherently safer than bare table saws.
BTW My slide table stops sliding before your hand
can reach the blade.
Use a hold down next to the fence as close to the
lifting blade as possible.
Install a splitter if possible (harder on a slide
table)
A second fence not even touching the board or a
feather board would help.

Design it and sell it them!

--
Mike
Watch for the bounce.
If ya didn't see it, ya didn't feel it.
If ya see it, it didn't go off.
Old Air Force Munitions Saying
IYAAYAS
"BoyntonStu" <[email protected]> wrote in message
news:dd5178ae-174d-4140-acdf-777d0808873b@k39g2000hsf.googlegroups.com...
> On Feb 3, 7:42 pm, "Bonehenge (B A R R Y)"
> <[email protected]> wrote:
>> On Sun, 3 Feb 2008 15:33:55 -0800 (PST), Father Haskell
>>
>> <[email protected]> wrote:
>>
>> >You want to be reaching across the blade?
>>
>> BINGO!
>
> No.
>
> You are standing on the teeth rising side of the table saw.
>
> Your sled has a handle between you and the blade.
>
> The sled has a stop and you cannot pull the sled off the table.
>
> The hold down(s) eliminate the need for hands anywhere near the blade.
>
> You pull the sled towards you.
>
> Any flying wood goes away from you.
>
> The sled could also have a backstop to trap anything flying its way.
>
> How is it possible for anyone or anything to be hit?

On Feb 3, 11:21 pm, [email protected] (J T) wrote:
> Sat, Feb 2, 2008, 2:41pm [email protected]
> (Jim Behning) doth sayeth:
> <snip> You now have two pieces of wood that you are trying to safely
> pass by the saw blade. <snip>
>
> I've read, and re-read, that, and still can't figure out what
> you're tryping to say. You've got ONE piece of wood, with two fences
> or one, until the blade passes thru the last of the wood.

If there is only one fence then the kerf can open up on
the outfeed side of the blade. With two fences it cannot,
so that greatly increases the chance that it will pinch the
blade as stresses are relieved in the wood being ripped.

With a fence and a half, wherein the half fence ends just
shy of the blade the kerf can open up, but the half
fence will not hold the stock as tightly against the
full fence as would a featherboard.

--

FF

> You pull the sled towards you.

Reaching across the blade.

Again, no.

when you are ripping a piece of 2' x 8' plywood and it is half
through.

Some times you walk around to the other side of the saw and you pull
the sheet through.

Are you then reaching across the blade?

This is what I am attmpting to describe.

On Feb 3, 3:14 pm, Tanus <[email protected]> wrote:
> Bonehenge (B A R R Y) wrote:
>
>
>
> > On Sat, 2 Feb 2008 18:09:42 -0800 (PST), BoyntonStu <[email protected]>
> > wrote:
>
> >> I have a sled.
>
> >> Using clamps the board is fixed.
>
> >> The sled has a stop.
>
> >> Why not stand on the other side and pull the sled instead of pushing
> >> it?
>
> >> The 'kickback' would go away from you.
>
> >> Completely safe?
>
> > Unsafe for other reasons, such as the mechanics of reaching long
> > distances, but safe for other reasons I'll mention below.
>
> > The bottom line: You don't understand kickback. The key to safely
> > and successfully using machine tools is a solid understanding of the
> > physics involved in each operation and using them to your advantage.
> > Fear based "safety" workarounds usually have unintended side effects,
> > at the minimum destroying accuracy or speed of work.
>
> > Boards clamped to sleds are not the same as boards trapped between a
> > fence and the rising back teeth of a saw blade. You need three
> > conditions for serious kickback:
>
> > 1. - Rising Teeth
> > 2. - A fence to trap the work against, to provide traction
> > 3. - Enough slop to allow the wood to rotate against the rising teeth,
> > or a board that pinches shut after being cut.
>
> > Ripping a board that's short and wide, or using a miter gauge and rip
> > fence together (without extra room to the side of the blade) can also
> > get ugly in a hurry.
>
> > You can prevent kickback by eliminating at least one of the conditions
> > above. For example, a splitter prevents the cut wood from pinching or
> > being grabbed by the rising teeth. A properly adjusted fence
> > eliminates the slop. Without traction (as on the clamped sled or the
> > offcut side of a rip), the possible force of kickback is greatly
> > reduced.
>
> > Here's a decent demo that looks like it's filmed in a school shop:
> > <http://www.metacafe.com/watch/910584/table_saw_kickback_demonstration/>
>
> > Some teachers will demonstrate the same thing using foam.
>
> I like that explanation, and there's
> another factor to be considered. A
> kickback "away from you" is still a
> kickback. Wood flies.
>
> To where?
>
> Wall with window?
>
> Priceless antique that's in the shop for
> repair?
>
> Your brand new (and priceless) Harbor
> Freight router that's just been lovingly
> unwrapped and awaiting its first plunge?
>
> Someone else in the shop who came in to
> announce supper?(This one may limit your
> ability to have children, even tho the
> kick back didn't hit YOU)
>
> --
> Tanus
>
> This is not really a sig.
>
> http://www.home.mycybernet.net/~waugh/shop/

If you are pulling a sled towards you, the push sled could have a
vertical plywood 'safety' shield you could swing into position..

Hold down, push fence, parallel fence, safety shield.

I can't think of kickback happening and if it possibly did occur, I
cannot imagine that the board would hit anything but the shield.

Is your sparkling new HF router safe now?

On Feb 3, 7:42 pm, "Bonehenge (B A R R Y)"
<[email protected]> wrote:
> On Sun, 3 Feb 2008 15:33:55 -0800 (PST), Father Haskell
>
> <[email protected]> wrote:
>
> >You want to be reaching across the blade?
>
> BINGO!

No.

You are standing on the teeth rising side of the table saw.

Your sled has a handle between you and the blade.

The sled has a stop and you cannot pull the sled off the table.

The hold down(s) eliminate the need for hands anywhere near the blade.

You pull the sled towards you.

Any flying wood goes away from you.

The sled could also have a backstop to trap anything flying its way.

How is it possible for anyone or anything to be hit?

On Sat, 2 Feb 2008 20:03:30 -0500, [email protected] (J T)
wrote:

>Sat, Feb 2, 2008, 2:41pm [email protected]
>(Jim Behning) doth posteth:
>Have you ever been shot in the belly by a piece of wood that the saw
>kicked back? Huge risk of increased kickback if you try that. You now
>have two pieces of wood that you are trying to safely pass by the saw
>blade. With just one fence the waste can lay on the table or fall off
>the table with marginal risk of getting tossed back by the blade.
>If your wood is not parallel you have chances for even more adventures
>in kickback and binding.
>
> If you stand out of line of the blade you won't get hit by
>kickback. When I was in high school shop class the teacher showed use
>what kickback was. He then told us not to do that. And I never hav
>
> I don't see a problem with two fences, if they are parallel to each
>other and the blade. I also don't see the need.
>
>
>
>JOAT - who does not welcome thread question e-mails..
>
>10 Out Of 10 Terrorists Prefer Hillary For President - Bumper Sticker
>
>I don't have a problem with a woman president - except for Hillary.

Yes, I do stand to the side.

My high school shop teacher was a room monitor. I do not recall any
teaching but that was over 30 years ago. I do recall the college shop
teacher teaching but I do not recall any lessons besides pull down on
the disconnect handle mounted 14 feet up on the ceiling before
servicing equipment. Oh, he also said no power sanders allowed. I do
not recall a lesson on the use of scrapers. One last lesson from the
college instructor. Two parts. Do not drop tools on the floor. Do not
stick your foot out to prevent a chisel from hitting the floor. Better
the floor and teacher wrath than a trip to the hospital.

On Feb 4, 5:29 pm, BoyntonStu <[email protected]> wrote:
> > You pull the sled towards you.
>
> Reaching across the blade.
>
> Again, no.
>
> when you are ripping a piece of 2' x 8' plywood and it is half
> through.
>
> Some times you walk around to the other side of the saw and you pull
> the sheet through.

4' deep outfeed table.

> Are you then reaching across the blade?
>
> This is what I am attmpting to describe.

You need someone to show you how to use a
tablesaw.

Jim Behning wrote:
> On Sat, 2 Feb 2008 20:03:30 -0500, [email protected] (J T)
> wrote:
>
>> Sat, Feb 2, 2008, 2:41pm
>> [email protected]
>> (Jim Behning) doth posteth:
>> Have you ever been shot in the belly by a piece of wood that the
>> saw
>> kicked back? Huge risk of increased kickback if you try that. You
>> now
>> have two pieces of wood that you are trying to safely pass by the
>> saw
>> blade. With just one fence the waste can lay on the table or fall
>> off
>> the table with marginal risk of getting tossed back by the blade.
>> If your wood is not parallel you have chances for even more
>> adventures in kickback and binding.
>>
>> If you stand out of line of the blade you won't get hit by
>> kickback. When I was in high school shop class the teacher showed
>> use what kickback was. He then told us not to do that. And I
>> never
>> hav
>>
>> I don't see a problem with two fences, if they are parallel to
>> each other and the blade. I also don't see the need.
>>
>>
>>
>> JOAT - who does not welcome thread question e-mails..
>>
>> 10 Out Of 10 Terrorists Prefer Hillary For President - Bumper
>> Sticker
>>
>> I don't have a problem with a woman president - except for Hillary.
>
> Yes, I do stand to the side.
>
> My high school shop teacher was a room monitor. I do not recall any
> teaching but that was over 30 years ago. I do recall the college
> shop
> teacher teaching but I do not recall any lessons besides pull down
> on
> the disconnect handle mounted 14 feet up on the ceiling before
> servicing equipment. Oh, he also said no power sanders allowed. I do
> not recall a lesson on the use of scrapers. One last lesson from the
> college instructor. Two parts. Do not drop tools on the floor. Do
> not
> stick your foot out to prevent a chisel from hitting the floor.

Lucky you. At least you knew what "sharp" was like. Wasn't until I
started doing my own sharpening that I found out that you don't try to
catch a chisel with your foot.

> Better
> the floor and teacher wrath than a trip to the hospital.

--
--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)

Bonehenge (B A R R Y) wrote:
> On Sat, 2 Feb 2008 18:09:42 -0800 (PST), BoyntonStu <[email protected]>
> wrote:
>
>
>> I have a sled.
>>
>> Using clamps the board is fixed.
>>
>> The sled has a stop.
>>
>> Why not stand on the other side and pull the sled instead of pushing
>> it?
>>
>>
>> The 'kickback' would go away from you.
>>
>>
>> Completely safe?
>
> Unsafe for other reasons, such as the mechanics of reaching long
> distances, but safe for other reasons I'll mention below.
>
> The bottom line: You don't understand kickback. The key to safely
> and successfully using machine tools is a solid understanding of the
> physics involved in each operation and using them to your advantage.
> Fear based "safety" workarounds usually have unintended side effects,
> at the minimum destroying accuracy or speed of work.
>
> Boards clamped to sleds are not the same as boards trapped between a
> fence and the rising back teeth of a saw blade. You need three
> conditions for serious kickback:
>
> 1. - Rising Teeth
> 2. - A fence to trap the work against, to provide traction
> 3. - Enough slop to allow the wood to rotate against the rising teeth,
> or a board that pinches shut after being cut.
>
> Ripping a board that's short and wide, or using a miter gauge and rip
> fence together (without extra room to the side of the blade) can also
> get ugly in a hurry.
>
> You can prevent kickback by eliminating at least one of the conditions
> above. For example, a splitter prevents the cut wood from pinching or
> being grabbed by the rising teeth. A properly adjusted fence
> eliminates the slop. Without traction (as on the clamped sled or the
> offcut side of a rip), the possible force of kickback is greatly
> reduced.
>
> Here's a decent demo that looks like it's filmed in a school shop:
> <http://www.metacafe.com/watch/910584/table_saw_kickback_demonstration/>
>
> Some teachers will demonstrate the same thing using foam.

I like that explanation, and there's
another factor to be considered. A
kickback "away from you" is still a
kickback. Wood flies.

To where?

Wall with window?

Priceless antique that's in the shop for
repair?

Your brand new (and priceless) Harbor
Freight router that's just been lovingly
unwrapped and awaiting its first plunge?

Someone else in the shop who came in to
announce supper?(This one may limit your
ability to have children, even tho the
kick back didn't hit YOU)

--
Tanus

This is not really a sig.

http://www.home.mycybernet.net/~waugh/shop/

BoyntonStu wrote:
<snip>

>
> If you are pulling a sled towards you, the push sled could have a
> vertical plywood 'safety' shield you could swing into position..
>
> Hold down, push fence, parallel fence, safety shield.
>
> I can't think of kickback happening and if it possibly did occur, I
> cannot imagine that the board would hit anything but the shield.
>
> Is your sparkling new HF router safe now?
>

I'm not sure if you purposefully missed
my point or you really believe that this
is safe.

If it's the former, and you're just
pulling my leg, consider it pulled.

If it's the latter, then I'm glad we
don't work together.

--
Tanus

This is not really a sig.

http://www.home.mycybernet.net/~waugh/shop/

On Sun, 3 Feb 2008 15:33:55 -0800 (PST), Father Haskell
<[email protected]> wrote:

>
>You want to be reaching across the blade?


BINGO!

On Sat, 2 Feb 2008 18:09:42 -0800 (PST), BoyntonStu <[email protected]>
wrote:


>I have a sled.
>
>Using clamps the board is fixed.
>
>The sled has a stop.
>
>Why not stand on the other side and pull the sled instead of pushing
>it?
>
>
>The 'kickback' would go away from you.
>
>
>Completely safe?

Unsafe for other reasons, such as the mechanics of reaching long
distances, but safe for other reasons I'll mention below.

The bottom line: You don't understand kickback. The key to safely
and successfully using machine tools is a solid understanding of the
physics involved in each operation and using them to your advantage.
Fear based "safety" workarounds usually have unintended side effects,
at the minimum destroying accuracy or speed of work.

Boards clamped to sleds are not the same as boards trapped between a
fence and the rising back teeth of a saw blade. You need three
conditions for serious kickback:

1. - Rising Teeth
2. - A fence to trap the work against, to provide traction
3. - Enough slop to allow the wood to rotate against the rising teeth,
or a board that pinches shut after being cut.

Ripping a board that's short and wide, or using a miter gauge and rip
fence together (without extra room to the side of the blade) can also
get ugly in a hurry.

You can prevent kickback by eliminating at least one of the conditions
above. For example, a splitter prevents the cut wood from pinching or
being grabbed by the rising teeth. A properly adjusted fence
eliminates the slop. Without traction (as on the clamped sled or the
offcut side of a rip), the possible force of kickback is greatly
reduced.

Here's a decent demo that looks like it's filmed in a school shop:
<http://www.metacafe.com/watch/910584/table_saw_kickback_demonstration/>

Some teachers will demonstrate the same thing using foam.

asmurff wrote:
> Design it and sell it them!
>

Rube Goldberg Tools <G>