I'm going to be working on a project where we will be
splitting many sonotubes ranging in diameter from 8"
to 16" and in length from 12' to 16'. We need to
rip them into perfect (as much as possible) half-rounds.

I'm thinking that there must be a jig I can build for
my tablesaw that will allow the tubes to be fed through
the blade that will make a very straight cut. A V notch
would keep the tube centered on the blade, but I
can't think of a way to make sure the cut doesn't
wander radially from one end to the other. The half
rounds are going to be placed on walls and need to
be super flat and straight.

One idea was to snap a chalk line along the length of
one side of the tube. Then, on the jig, have an
arm that extends over the top of the tube that has
an indicator on it showing the blade position. As
the tube is fed through the blade, keep the chalk
line on that indicator. Then flip the tube over,
tape the cut just made so the tube doesn't fall
apart as the second cut is made. Run the tube
through again, this time using the first cut as
the guide line on the indicator.

Here's a picture of that idea:
http://www.proudviews.com/TubeRipper.jpg

Would this work or is there a better way to do
this?

-- TRW
_______________________________________
t i m . w i t o r t
_______________________________________

"Tim Witort" wrote in message
.131...
I'm going to be working on a project where we will be
splitting many sonotubes ranging in diameter from 8"
to 16" and in length from 12' to 16'. We need to
rip them into perfect (as much as possible) half-rounds.

I'm thinking that there must be a jig I can build for
my tablesaw that will allow the tubes to be fed through
the blade that will make a very straight cut. A V notch
would keep the tube centered on the blade, but I
can't think of a way to make sure the cut doesn't
wander radially from one end to the other. The half
rounds are going to be placed on walls and need to
be super flat and straight.

One idea was to snap a chalk line along the length of
one side of the tube. Then, on the jig, have an
arm that extends over the top of the tube that has
an indicator on it showing the blade position. As
the tube is fed through the blade, keep the chalk
line on that indicator. Then flip the tube over,
tape the cut just made so the tube doesn't fall
apart as the second cut is made. Run the tube
through again, this time using the first cut as
the guide line on the indicator.

Here's a picture of that idea:
http://www.proudviews.com/TubeRipper.jpg

Would this work or is there a better way to do
this?

-- TRW
_______________________________________
t i m . w i t o r t
_______________________________________

can you find a large band saw?

"Tim Witort" wrote:

I'm going to be working on a project where we will be
splitting many sonotubes ranging in diameter from 8"
to 16" and in length from 12' to 16'. We need to
rip them into perfect (as much as possible) half-rounds.

I'm thinking that there must be a jig I can build for
my tablesaw that will allow the tubes to be fed through
the blade that will make a very straight cut.
snip

You don't want to go down the table saw road.

Might consider the following:

Build a dedicated jig for each tube size that will clamp the tube in
position and guide a circular saw to make the first cut.

After first cut rotate 180 degrees and locate in final position with a
2nd jig to insure accurate 2nd cut.

Moving the cutting blade rather than moving the tube will make the job
a whole lot easier, IMHO.

Lew

On Thu, 05 Jun 2008 16:18:45 -0500, (Tim
Witort) wrote:

I'm going to be working on a project where we will be
splitting many sonotubes ranging in diameter from 8"
to 16" and in length from 12' to 16'. We need to
rip them into perfect (as much as possible) half-rounds.

I'm thinking that there must be a jig I can build for
my tablesaw that will allow the tubes to be fed through
the blade that will make a very straight cut. A V notch
would keep the tube centered on the blade, but I
can't think of a way to make sure the cut doesn't
wander radially from one end to the other. The half
rounds are going to be placed on walls and need to
be super flat and straight.

One idea was to snap a chalk line along the length of
one side of the tube. Then, on the jig, have an
arm that extends over the top of the tube that has
an indicator on it showing the blade position. As
the tube is fed through the blade, keep the chalk
line on that indicator. Then flip the tube over,
tape the cut just made so the tube doesn't fall
apart as the second cut is made. Run the tube
through again, this time using the first cut as
the guide line on the indicator.

Here's a picture of that idea:
http://www.proudviews.com/TubeRipper.jpg

Would this work or is there a better way to do
this?

-- TRW
_______________________________________
t i m . w i t o r t
_______________________________________


Tim:

I'd fix the tubes up onto a section of extension ladder that was
resting on as many sawhorses as you would need to maintain a level
line.

Then I'd cut two square pieces of ply to the dimensions of the
diameter of the largest Sonotube (so that it could be recut to the
smaller diameter when needed). I'd make a mark at the centerline of
the top edge and use this to lay out a chalk line on the Sonotube.

Then I'd hotmelt a piece of ply to the base of your circular saw and
hot melt a couple of blocks to that, so that the saw would bear on
three points - the cut line and the two blocks.

Then I'd cut to within a sixteenth of the inside face of the tube,
flip it over and do the same trick 180 degrees away.

I'd then cut through the remaining sixteenth with a utility knife and
clean up the edge with a sander.


Just my take on it, you understand.




Then
Regards,

Tom

Thos.J.Watson - Cabinetmaker
tjwatson1ATcomcastDOTnet
www.home.comcast.net/~tjwatson1

"Tim Witort" wrote:
I'm going to be working on a project where we will be
splitting many sonotubes ranging in diameter from 8"
to 16" and in length from 12' to 16'. *We need to
rip them into perfect (as much as possible) half-rounds.

I'm thinking that there must be a jig I can build for
my tablesaw that will allow the tubes to be fed through
the blade that will make a very straight cut.

What you want to do is build a v-shaped jig like you mentioned, and
directly behind the blade you'll build in a "splitter". This is
straight piece of wood the thickness of your saw blade that will serve
to keep the kerf you just cut from closing up, and will also prevent
the sonotube from rotating once you've started your cut. The only
issue is to be careful you make the second cut 180 degrees around from
the first. Good luck!

JP

charlie seemed to utter in :


"Tim Witort" wrote in message
.131...
I'm going to be working on a project where we will be
splitting many sonotubes ranging in diameter from 8"
to 16" and in length from 12' to 16'. We need to
rip them into perfect (as much as possible) half-rounds.

I'm thinking that there must be a jig I can build for
my tablesaw that will allow the tubes to be fed through
the blade that will make a very straight cut. A V notch
would keep the tube centered on the blade, but I
can't think of a way to make sure the cut doesn't
wander radially from one end to the other. The half
rounds are going to be placed on walls and need to
be super flat and straight.

One idea was to snap a chalk line along the length of
one side of the tube. Then, on the jig, have an
arm that extends over the top of the tube that has
an indicator on it showing the blade position. As
the tube is fed through the blade, keep the chalk
line on that indicator. Then flip the tube over,
tape the cut just made so the tube doesn't fall
apart as the second cut is made. Run the tube
through again, this time using the first cut as
the guide line on the indicator.

Here's a picture of that idea:
http://www.proudviews.com/TubeRipper.jpg

Would this work or is there a better way to do this?

-- TRW
_______________________________________
t i m . w i t o r t
_______________________________________

can you find a large band saw?

Not *that* large! The only band saws I know that can
cut 16" material are huge industrial machines.

-- TRW
_______________________________________
t i m . w i t o r t
_______________________________________

Lew Hodgett seemed to utter in news:dZY1k.11199$%Z1.1820@trnddc05:


"Tim Witort" wrote:

I'm going to be working on a project where we will be
splitting many sonotubes ranging in diameter from 8"
to 16" and in length from 12' to 16'. We need to
rip them into perfect (as much as possible) half-rounds.

I'm thinking that there must be a jig I can build for
my tablesaw that will allow the tubes to be fed through
the blade that will make a very straight cut.
snip

You don't want to go down the table saw road.

Might consider the following:

Build a dedicated jig for each tube size that will clamp the tube in
position and guide a circular saw to make the first cut.

After first cut rotate 180 degrees and locate in final position with a
2nd jig to insure accurate 2nd cut.

Moving the cutting blade rather than moving the tube will make the job
a whole lot easier, IMHO.

Lew

Thanks for the idea, I'll have to think about that one.

-- TRW
_______________________________________
t i m . w i t o r t
_______________________________________

Jay Pique seemed to utter in news:408ad1f8-e6bd-4380-b1aa-
:

"Tim Witort" wrote:
I'm going to be working on a project where we will be
splitting many sonotubes ranging in diameter from 8"
to 16" and in length from 12' to 16'. *We need to
rip them into perfect (as much as possible) half-rounds.

I'm thinking that there must be a jig I can build for
my tablesaw that will allow the tubes to be fed through
the blade that will make a very straight cut.

What you want to do is build a v-shaped jig like you mentioned, and
directly behind the blade you'll build in a "splitter". This is
straight piece of wood the thickness of your saw blade that will serve
to keep the kerf you just cut from closing up, and will also prevent
the sonotube from rotating once you've started your cut. The only
issue is to be careful you make the second cut 180 degrees around from
the first. Good luck!

JP

Yeah, I thought about having a 4' long splitter going
out the back of the saw - maybe 1/8" aluminum L bar.
That would alow the kerf to ride on the splitter
like a fence. Thanks for the idea, Jay.

-- TRW
_______________________________________
t i m . w i t o r t
_______________________________________

The jig in your picture looks a lot like a radial arm saw except that
instead of a pointer indicating the location of the blade down below, you'd
have the actual blade that you could see up above. There will always be
people who freak out at the thought of ripping with a RAS, but the idea is
so crazy it just might work.

Lee

--
To e-mail, replace "bucketofspam" with "dleegordon"

_________________________________
Lee Gordon
http://www.leegordonproductions.com

use your bandsaw it will be less dangerous and give you a smo
tther cut
"Tim Witort" wrote in message
.131...
I'm going to be working on a project where we will be
splitting many sonotubes ranging in diameter from 8"
to 16" and in length from 12' to 16'. We need to
rip them into perfect (as much as possible) half-rounds.

I'm thinking that there must be a jig I can build for
my tablesaw that will allow the tubes to be fed through
the blade that will make a very straight cut. A V notch
would keep the tube centered on the blade, but I
can't think of a way to make sure the cut doesn't
wander radially from one end to the other. The half
rounds are going to be placed on walls and need to
be super flat and straight.

One idea was to snap a chalk line along the length of
one side of the tube. Then, on the jig, have an
arm that extends over the top of the tube that has
an indicator on it showing the blade position. As
the tube is fed through the blade, keep the chalk
line on that indicator. Then flip the tube over,
tape the cut just made so the tube doesn't fall
apart as the second cut is made. Run the tube
through again, this time using the first cut as
the guide line on the indicator.

Here's a picture of that idea:
http://www.proudviews.com/TubeRipper.jpg

Would this work or is there a better way to do
this?

-- TRW
_______________________________________
t i m . w i t o r t
_______________________________________

On Jun 5, 5:18*pm, (Tim Witort) wrote:
I'm going to be working on a project where we will be
splitting many sonotubes ranging in diameter from 8"
to 16" and in length from 12' to 16'. *We need to
rip them into perfect (as much as possible) half-rounds.

I'm thinking that there must be a jig I can build for
my tablesaw that will allow the tubes to be fed through
the blade that will make a very straight cut. *A V notch
would keep the tube centered on the blade, but I
can't think of a way to make sure the cut doesn't
wander radially from one end to the other. *The half
rounds are going to be placed on walls and need to
be super flat and straight.

One idea was to snap a chalk line along the length of
one side of the tube. *Then, on the jig, have an
arm that extends over the top of the tube that has
an indicator on it showing the blade position. *As
the tube is fed through the blade, keep the chalk
line on that indicator. *Then flip the tube over,
tape the cut just made so the tube doesn't fall
apart as the second cut is made. *Run the tube
through again, this time using the first cut as
the guide line on the indicator.

Here's a picture of that idea:http://www.proudviews.com/TubeRipper.jpg

Would this work or is there a better way to do
this?

-- TRW
_______________________________________
t i m *. *w i t o r t
_______________________________________

How many of those cuts do you have to make?
I have thought of a jig, but the quantities will have make it all
worth it.

Robatoy seemed to utter in news:ac054c7b-e4ab-4139-bb35-8cea0a5f8ee9@
79g2000hsk.googlegroups.com:

On Jun 5, 5:18*pm, (Tim Witort) wrote:
I'm going to be working on a project where we will be
splitting many sonotubes ranging in diameter from 8"
to 16" and in length from 12' to 16'. *We need to
rip them into perfect (as much as possible) half-rounds.

I'm thinking that there must be a jig I can build for
my tablesaw that will allow the tubes to be fed through
the blade that will make a very straight cut. *A V notch
would keep the tube centered on the blade, but I
can't think of a way to make sure the cut doesn't
wander radially from one end to the other. *The half
rounds are going to be placed on walls and need to
be super flat and straight.

One idea was to snap a chalk line along the length of
one side of the tube. *Then, on the jig, have an
arm that extends over the top of the tube that has
an indicator on it showing the blade position. *As
the tube is fed through the blade, keep the chalk
line on that indicator. *Then flip the tube over,
tape the cut just made so the tube doesn't fall
apart as the second cut is made. *Run the tube
through again, this time using the first cut as
the guide line on the indicator.

Here's a picture of that idea:http://www.proudviews.com/TubeRipper.jpg

Would this work or is there a better way to do this?

-- TRW
_______________________________________
t i m *. *w i t o r t
_______________________________________

How many of those cuts do you have to make?
I have thought of a jig, but the quantities will have make it all
worth it.

Roughly 100 Sonotubes will need to be split for this project.

-- TRW
_______________________________________
t i m . w i t o r t
_______________________________________

jim seemed to utter in :

use your bandsaw it will be less dangerous and give you a smo
tther cut

I don't have access to a bandsaw with a 16" cutting height.
Heck, I don't even have access to a bandsaw with an 8"
cutting height! The big commercial bandsaws can do 16",
but that's not an option on this project.

-- TRW
_______________________________________
t i m . w i t o r t
_______________________________________

On Fri, 06 Jun 2008 18:31:12 -0500, (Tim
Witort) wrote:

Roughly 100 Sonotubes will need to be split for this project.

For 100 tubes, a jig is definitely worth it.

What about a foam insert? It could be solid or a series of disks.
-- or --
A "case" that would guide a circular or jig saw along the top, or a
table saw along the bottom? You could tape the first cut together to
do the second.




---------------------------------------------
** http://www.bburke.com/woodworking.html **
---------------------------------------------

Lee Gordon seemed to utter in
:

The jig in your picture looks a lot like a radial arm saw except that
instead of a pointer indicating the location of the blade down below,
you'd have the actual blade that you could see up above. There will
always be people who freak out at the thought of ripping with a RAS,
but the idea is so crazy it just might work.

Lee


Yeah, I see the resemblance. If I had a RAS, I might
consider that one. My only saw options are tablesaw,
skill saw, jig saw, and recip saw. Seemed the tablesaw
was my best option for getting a clean, straight cut.

-- TRW
_______________________________________
t i m . w i t o r t
_______________________________________

On Jun 5, 5:18*pm, (Tim Witort) wrote:
I'm going to be working on a project where we will be
splitting many sonotubes ranging in diameter from 8"
to 16" and in length from 12' to 16'. *We need to
rip them into perfect (as much as possible) half-rounds.

I'm thinking that there must be a jig I can build for
my tablesaw that will allow the tubes to be fed through
the blade that will make a very straight cut. *A V notch
would keep the tube centered on the blade, but I
can't think of a way to make sure the cut doesn't
wander radially from one end to the other. *The half
rounds are going to be placed on walls and need to
be super flat and straight.

One idea was to snap a chalk line along the length of
one side of the tube. *Then, on the jig, have an
arm that extends over the top of the tube that has
an indicator on it showing the blade position. *As
the tube is fed through the blade, keep the chalk
line on that indicator. *Then flip the tube over,
tape the cut just made so the tube doesn't fall
apart as the second cut is made. *Run the tube
through again, this time using the first cut as
the guide line on the indicator.

Here's a picture of that idea:http://www.proudviews.com/TubeRipper.jpg

Would this work or is there a better way to do
this?

-- TRW
_______________________________________
t i m *. *w i t o r t
_______________________________________

I think your ideal is the way to go, but instead of wedges use tall
fences on either side. I think you'll find the wedges would have to be
very big in order to "wedge" the tube. Where as the tall fence will
hold tube in place.

If I had a RAS, I might
consider that one. My only saw options are tablesaw,
skill saw, jig saw, and recip saw. Seemed the tablesaw
was my best option for getting a clean, straight cut.

Depending on how long the tubes are, here's one more option. Build a
rectangular frame with wedges running along the bottom of the long sides, so
you can clamp the fixture to the sonotube and run a router with a straight
cutting bit from one end to the other. That would give you a clean cut and
allow you to see what you were doing.

Lee

--
To e-mail, replace "bucketofspam" with "dleegordon"

_________________________________
Lee Gordon
http://www.leegordonproductions.com

On Jun 6, 7:31*pm, (Tim Witort) wrote:
Robatoy seemed to utter in news:ac054c7b-e4ab-4139-bb35-8cea0a5f8ee9@
79g2000hsk.googlegroups.com:





On Jun 5, 5:18*pm, (Tim Witort) wrote:
I'm going to be working on a project where we will be
splitting many sonotubes ranging in diameter from 8"
to 16" and in length from 12' to 16'. *We need to
rip them into perfect (as much as possible) half-rounds.

I'm thinking that there must be a jig I can build for
my tablesaw that will allow the tubes to be fed through
the blade that will make a very straight cut. *A V notch
would keep the tube centered on the blade, but I
can't think of a way to make sure the cut doesn't
wander radially from one end to the other. *The half
rounds are going to be placed on walls and need to
be super flat and straight.

One idea was to snap a chalk line along the length of
one side of the tube. *Then, on the jig, have an
arm that extends over the top of the tube that has
an indicator on it showing the blade position. *As
the tube is fed through the blade, keep the chalk
line on that indicator. *Then flip the tube over,
tape the cut just made so the tube doesn't fall
apart as the second cut is made. *Run the tube
through again, this time using the first cut as
the guide line on the indicator.

Here's a picture of that idea:http://www.proudviews.com/TubeRipper.jpg

Would this work or is there a better way to do this?

-- TRW
_______________________________________
t i m *. *w i t o r t
_______________________________________

How many of those cuts do you have to make?
I have thought of a jig, but the quantities will have make it all
worth it.

Roughly 100 Sonotubes will need to be split for this project.


I'm curious - what are you making?

JP

The simplest jig would be a piece of plywood cut to length and ripped
the exact diameter of the tube. Firmly attach to the tube and run the
plywood against the fence. Flip the assembly end for end for the second
cut.

You may need a helper and some type of feather board to hold the plywood
and tube tight to the fence.

I would check to see if the Sona tube makers can rip them first. If
not I would use it as an excuss to buy a Rikon 14" bandsaw, and for
the largest or all if the excuss idea didnt work is the use a jig saw
with straight edge clamped. . Look to see if theres a co-op workshop
to rent shop space and use there bandsaw.Where are located maybe
someone knows of shop space

Jay Pique seemed to utter in
:

On Jun 6, 7:31*pm, (Tim Witort) wrote:
Robatoy seemed to utter in news:ac054c7b-e4ab-4139-bb35-8cea0a5f8ee9@
79g2000hsk.googlegroups.com:





On Jun 5, 5:18*pm, (Tim Witort) wrote:
I'm going to be working on a project where we will be
splitting many sonotubes ranging in diameter from 8"
to 16" and in length from 12' to 16'. *We need to
rip them into perfect (as much as possible) half-rounds.

I'm thinking that there must be a jig I can build for
my tablesaw that will allow the tubes to be fed through
the blade that will make a very straight cut. *A V notch
would keep the tube centered on the blade, but I
can't think of a way to make sure the cut doesn't
wander radially from one end to the other. *The half
rounds are going to be placed on walls and need to
be super flat and straight.

One idea was to snap a chalk line along the length of
one side of the tube. *Then, on the jig, have an
arm that extends over the top of the tube that has
an indicator on it showing the blade position. *As
the tube is fed through the blade, keep the chalk
line on that indicator. *Then flip the tube over,
tape the cut just made so the tube doesn't fall
apart as the second cut is made. *Run the tube
through again, this time using the first cut as
the guide line on the indicator.

Here's a picture of that
idea:http://www.proudviews.com/TubeRipper.jpg

Would this work or is there a better way to do this?

-- TRW
_______________________________________
t i m *. *w i t o r t
_______________________________________

How many of those cuts do you have to make?
I have thought of a jig, but the quantities will have make it all
worth it.

Roughly 100 Sonotubes will need to be split for this project.


I'm curious - what are you making?

We're doing an acoustic renovation on an auditorium.
The half-tubes need to be placed on the walls at
specific locations to tune the acoustics of the room.

-- TRW
_______________________________________
t i m . w i t o r t
_______________________________________

Rick M seemed to utter in :

Tim,

Build a 3-sided box that will hold the sonotube (only need 1/2 the
diameter on the box top and bottom). Make the box a bit longer than the
sonotube and install a stop inside on both ends. Clamp the sonotube to
the box on the center of the full-length side so the clamps clear the
fence .

Slide the box (full length side against the table saw fence) and cut
one side at a time. This will give you a smooth edge, repeatable cuts,
and a safe means to handle the sonotube.

After cutting lengthwise, remove from the box and repeat.

You will have to flip the box and tube to make the second cut, but with
two people, you should not have any issues.

To allow easier tracking, you might glue a guide strip on both of the
short sides that sets in the miter slot on the table saw ... thus
eliminating the fence (and the potential interference with the clamps),
and ensuring you always track the entire cut.

Hope this helps.

Good idea, Rick. I think I'm starting to get a good
design in mind now...

-- TRW
_______________________________________
t i m . w i t o r t
_______________________________________

You've got the right idea with the V-jig. You can make it large enough
to handle your largest stock and it will work for all of them.
Here's a trick to keep the tube from twisting...
Make the jig extend at least a foot past the blade on your tablesaw,
just run it through the saw to create a kerf, then us a slim piece of
metal standing in the kerf behind the saw. The kerf in the tube will
go on either side of the metal and prevent the tube from twisting.

I use a smaller setup just like this to split dowels.

Jack


On Thu, 05 Jun 2008 16:18:45 -0500, (Tim
Witort) wrote:

I'm going to be working on a project where we will be
splitting many sonotubes ranging in diameter from 8"
to 16" and in length from 12' to 16'. We need to
rip them into perfect (as much as possible) half-rounds.

I'm thinking that there must be a jig I can build for
my tablesaw that will allow the tubes to be fed through
the blade that will make a very straight cut. A V notch
would keep the tube centered on the blade, but I
can't think of a way to make sure the cut doesn't
wander radially from one end to the other. The half
rounds are going to be placed on walls and need to
be super flat and straight.

One idea was to snap a chalk line along the length of
one side of the tube. Then, on the jig, have an
arm that extends over the top of the tube that has
an indicator on it showing the blade position. As
the tube is fed through the blade, keep the chalk
line on that indicator. Then flip the tube over,
tape the cut just made so the tube doesn't fall
apart as the second cut is made. Run the tube
through again, this time using the first cut as
the guide line on the indicator.

Here's a picture of that idea:
http://www.proudviews.com/TubeRipper.jpg

Would this work or is there a better way to do
this?

-- TRW
_______________________________________
t i m . w i t o r t
_______________________________________

Tim Witort wrote:
I'm going to be working on a project where we will be
splitting many sonotubes ranging in diameter from 8"
to 16" and in length from 12' to 16'. We need to
rip them into perfect (as much as possible) half-rounds.

I'm thinking that there must be a jig I can build for
my tablesaw that will allow the tubes to be fed through
the blade that will make a very straight cut. A V notch
would keep the tube centered on the blade, but I
can't think of a way to make sure the cut doesn't
wander radially from one end to the other. The half
rounds are going to be placed on walls and need to
be super flat and straight.

One idea was to snap a chalk line along the length of
one side of the tube. Then, on the jig, have an
arm that extends over the top of the tube that has
an indicator on it showing the blade position. As
the tube is fed through the blade, keep the chalk
line on that indicator. Then flip the tube over,
tape the cut just made so the tube doesn't fall
apart as the second cut is made. Run the tube
through again, this time using the first cut as
the guide line on the indicator.

The problem is the lack of a reference face.

You make a long-plank-with-V-Seats and clamp
it to the tube. You now have a composite
object with a nice reference face to run against the fence.

Cut, flip end-for-end (so the reference is still against the face),
do the other cut.

BugBear

Tim Witort seemed to utter in news:Xns9AB85EDE98708timwitortwrotethis@
216.196.97.131:

Jay Pique seemed to utter in
:

On Jun 6, 7:31*pm, (Tim Witort) wrote:
Robatoy seemed to utter in news:ac054c7b-e4ab-4139-bb35-8cea0a5f8ee9@
79g2000hsk.googlegroups.com:





On Jun 5, 5:18*pm, (Tim Witort) wrote:
I'm going to be working on a project where we will be
splitting many sonotubes ranging in diameter from 8"
to 16" and in length from 12' to 16'. *We need to
rip them into perfect (as much as possible) half-rounds.

I'm thinking that there must be a jig I can build for
my tablesaw that will allow the tubes to be fed through
the blade that will make a very straight cut. *A V notch
would keep the tube centered on the blade, but I
can't think of a way to make sure the cut doesn't
wander radially from one end to the other. *The half
rounds are going to be placed on walls and need to
be super flat and straight.

One idea was to snap a chalk line along the length of
one side of the tube. *Then, on the jig, have an
arm that extends over the top of the tube that has
an indicator on it showing the blade position. *As
the tube is fed through the blade, keep the chalk
line on that indicator. *Then flip the tube over,
tape the cut just made so the tube doesn't fall
apart as the second cut is made. *Run the tube
through again, this time using the first cut as
the guide line on the indicator.

Here's a picture of that
idea:http://www.proudviews.com/TubeRipper.jpg

Would this work or is there a better way to do this?

-- TRW
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t i m *. *w i t o r t
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How many of those cuts do you have to make?
I have thought of a jig, but the quantities will have make it all
worth it.

Roughly 100 Sonotubes will need to be split for this project.


I'm curious - what are you making?

We're doing an acoustic renovation on an auditorium.
The half-tubes need to be placed on the walls at
specific locations to tune the acoustics of the room.

I settled on a design and we have almost finished splitting
all of the Sonotubes. The jig I ended up making was a 16'
long piece of plywood 18" wide as the jig base. Onto this
was attached a movable "fence" that also went the 16' length.
For the 16" diameter tubes, the jig fence was placed 8"
from the edge of the jig base. The tubes were clamped to
the jig fence at both ends, then the jig was run through
the tablesaw with the saw fence set at 18". This gave us
very straight, quick cuts. Then we rolled the tube 180
degrees, used a framing square to confirm that the first
cut was rotated directly above the next cut. Clamped again
and ran through the second cut. I used a feather board
to keep the jig against the saw fence and roller stands
on the infeed and outfeed to support the jig.

Thanks for everyone's input!

-- TRW
_______________________________________
t i m . w i t o r t
_______________________________________