I'm making formwork for concrete blocks, essentially 8" boxes, out of
plywood.
It would be better if my saw cuts were exactly 90 degrees, but I'm not
visually accurate enough. I can do better by holding a square to the
side of the saw, but could do with a third arm.
Is there an easy way or a carpenter's technique that I'm missing?

Thanks Tony

How I was taught to cut to the line:

(I'll take it as read that you've marked your line accurately and
sufficiently boldly that you can follow it - *around all 4 faces*).

1. Saw with the widest face towards you if possible.

2. Get the saw embedded in the rearmost portion of the line on that
widest face, only as far as required to stop the saw sliding side to
side (use your left thumb to position the saw).

3. Extend the saw cut across that widest face, *but don't go any
deeper at the back*. i.e. your eyes are only following the point where
the saw enters the top of the face and keeping *that* on the line.

4. Once you have your saw cut across the widest face (just a groove in
fact), then start following the line down the front (but *still* no
deeper at the back) until you've sawn half-way through (but in a
triangular shape). i.e. You're dropping the handle end of the saw
relative to the tip.

5. If you're less experienced you can turn the job round and repeat
step 4. Or once confident - use your thumb and eye to keep the saw
upright as you saw down at the back - but *not* sawing out the central
mass. You're dropping the tip end of the saw this time relative to the
handle.

6. Finally saw out the central mass.

This technique creates guides for sawing the parts you can't see, from
the parts you can see. It also considerably reduces damage from the
last part of a cut splitting away a corner.

This is overkill for handsawing shuttering - it's the kind of thing
that gives you sub-millimetre precision for joinery - but once learnt
becomes instinctive.

"tonyjeffs" wrote in message
...
I'm making formwork for concrete blocks, essentially 8" boxes, out of
plywood.
It would be better if my saw cuts were exactly 90 degrees, but I'm not
visually accurate enough. I can do better by holding a square to the
side of the saw, but could do with a third arm.
Is there an easy way or a carpenter's technique that I'm missing?

A mitre box.

http://www.stanleytools.com/default....GORY=MITRE+BOX

You can also put all the careful work into making a sawing guide. Get a
couple of bits of timber, about 2" x 2", taller if you prefer more guidance
for keeping your saw vertical, long enough to span the timber to be cut and
overhang both sides. Under each end, fit a packing piece of timber as thick
as the depth of cut you want to make, positioned so as to just drop across
the timber to be cut. Connect the two main bits by screwing joining timbers
up under the packing pieces, so that the two main bits are just wide enough
apart to accept the saw blade. Make the joining timbers long enough so that,
when you drop the guide over the timber, it holds the sawing slot at right
angles to the timber. You now have a guide that will keep you cut square,
help keep the saw vertical and show you how deep to cut. If the cuts are all
at the same distance from the end of the timber, you can also add a stop for
that.

Colin Bignell

"tonyjeffs" wrote in message
...
I'm making formwork for concrete blocks, essentially 8" boxes, out of
plywood.
It would be better if my saw cuts were exactly 90 degrees, but I'm not
visually accurate enough. I can do better by holding a square to the
side of the saw, but could do with a third arm.
Is there an easy way or a carpenter's technique that I'm missing?

Thanks Tony

I'm assuming the boxes have already been assembled?

Make a sleeve out of 2x2 wood that fits over the boxes so that you have to
weave the 2x2 boxed sleeve over the shuttered box.
Measure the sleeve from the edges of each four sides so that its level all
round,do this to where the lines needs to be cut.
Pin/nail the sleeve to four sides so that it doesn't move.
Saw all the way round using the sleeve as a guide for the saw..

"tonyjeffs" wrote in message
...
I'm making formwork for concrete blocks, essentially 8" boxes, out of
plywood.
It would be better if my saw cuts were exactly 90 degrees, but I'm not
visually accurate enough. I can do better by holding a square to the
side of the saw, but could do with a third arm.
Is there an easy way or a carpenter's technique that I'm missing?

Thanks Tony

I'm a bit confused how you're attempting to make these (shuttered boxes) as
they're called on site.

Basically alls you do is measure the correct size of the panels,make sure
they're straight at the edges with a set square.
Nail 2x2 pieces of wood to each end of the panels then screw the panels
together via the 2x2 wood.
This will then be as square as you will get without having to saw the box
constructed.

"tonyjeffs" wrote in message
...
I'm making formwork for concrete blocks, essentially 8" boxes, out of
plywood.
It would be better if my saw cuts were exactly 90 degrees, but I'm not
visually accurate enough. I can do better by holding a square to the
side of the saw, but could do with a third arm.
Is there an easy way or a carpenter's technique that I'm missing?

Thanks Tony


Mark it up and clamp a piece of 2 x 2 along the line and use the side
of the 2 x 2 to guide the saw.

Arthur

On Tue, 24 Jun 2008 21:05:02 -0700 (PDT), tonyjeffs wrote:

I'm making formwork for concrete blocks, essentially 8" boxes, out of
plywood.
It would be better if my saw cuts were exactly 90 degrees, but I'm not
visually accurate enough. I can do better by holding a square to the
side of the saw, but could do with a third arm.
Is there an easy way or a carpenter's technique that I'm missing?

Thanks Tony

Err, others have suggested 'mechanical' ways to keep the saw blade on the
line, but are you holding the saw properly? Are you (wrongly) wrapping your
index finger around the saw handle? That's the most obvious reason for not
making controlled cuts with a saw.

Your index finger should be extended and point down towards the end of the
saw blade.

--
the dot wanderer at tesco dot net

On Tue, 24 Jun 2008 21:05:02 -0700 (PDT), tonyjeffs
wrote:

I'm making formwork for concrete blocks, essentially 8" boxes, out of
plywood.
It would be better if my saw cuts were exactly 90 degrees, but I'm not
visually accurate enough. I can do better by holding a square to the
side of the saw, but could do with a third arm.
Is there an easy way or a carpenter's technique that I'm missing?

Thanks Tony

You can make a shooting block. You need a jack plane. That will get
you your right angle. See http://tinyurl.com/58lduf and scroll up to
page 95 (this takes you to Google Books displaying The Practical
Woodworker).

MM

On 26 Jun, 09:13, MM wrote:
On Tue, 24 Jun 2008 21:05:02 -0700 (PDT), tonyjeffs


You can make a shooting block. You need a jack plane. That will get
you your right angle. Seehttp://tinyurl.com/58ldufand scroll up to
page 95 (this takes you to Google Books displaying The Practical
Woodworker).

MM

Thanks for all the suggestions. Some are so good that Im wondering
"Why couldn't I think of that?". I'm confident I can do it now. I'm
also inspired to make a drill guide to ensure my drill holes are
perpendicular; - an appropriately sized block of wood with a true hole
through it.

cheers
Tony

tonyjeffs wrote:
On 26 Jun, 09:13, MM wrote:
On Tue, 24 Jun 2008 21:05:02 -0700 (PDT), tonyjeffs

You can make a shooting block. You need a jack plane. That will get
you your right angle. Seehttp://tinyurl.com/58ldufand scroll up to
page 95 (this takes you to Google Books displaying The Practical
Woodworker).

MM

Thanks for all the suggestions. Some are so good that Im wondering
"Why couldn't I think of that?". I'm confident I can do it now. I'm
also inspired to make a drill guide to ensure my drill holes are
perpendicular; - an appropriately sized block of wood with a true hole
through it.

cheers
Tony

I've got a thing like a plunging router frame. Woolcraft I think. Not
expensive and comes in very handy once in a while. Letter boxes etc

On 28 Jun, 09:30, stuart noble wrote:
tonyjeffs wrote:
On 26 Jun, 09:13, MM wrote:
On Tue, 24 Jun 2008 21:05:02 -0700 (PDT), tonyjeffs

You can make a shooting block. You need a jack plane. That will get
you your right angle. Seehttp://tinyurl.com/58ldufandscroll up to
page 95 (this takes you to Google Books displaying The Practical
Woodworker).

MM

Thanks for all the suggestions. Some are so good that Im wondering
"Why couldn't I think of that?". I'm confident I can do it now. I'm
also inspired to make a drill guide to ensure my drill holes are
perpendicular; - an appropriately sized block of wood with a true hole
through it.

cheers
Tony

I've got a thing like a plunging router frame. Woolcraft I think. Not
expensive and comes in very handy once in a while. Letter boxes etc- Hide quoted text -

- Show quoted text -

Stuart
An elderly guy in our street loaned me one of them many years ago.
Really good. I assumed it was one of those ideas that never took off
and was no longer available... But here it is:
http://www.woodcraft.com/family.aspx?FamilyId=3121
I might buy one.
Tony

"tonyjeffs" wrote in message
...
On 28 Jun, 09:30, stuart noble wrote:
tonyjeffs wrote:
On 26 Jun, 09:13, MM wrote:
On Tue, 24 Jun 2008 21:05:02 -0700 (PDT), tonyjeffs

You can make a shooting block. You need a jack plane. That will get
you your right angle. Seehttp://tinyurl.com/58ldufandscroll up to
page 95 (this takes you to Google Books displaying The Practical
Woodworker).

MM

Thanks for all the suggestions. Some are so good that Im wondering
"Why couldn't I think of that?". I'm confident I can do it now. I'm
also inspired to make a drill guide to ensure my drill holes are
perpendicular; - an appropriately sized block of wood with a true hole
through it.

cheers
Tony

I've got a thing like a plunging router frame. Woolcraft I think. Not
expensive and comes in very handy once in a while. Letter boxes etc-
Hide quoted text -

- Show quoted text -

Stuart
An elderly guy in our street loaned me one of them many years ago.
Really good. I assumed it was one of those ideas that never took off
and was no longer available... But here it is:
http://www.woodcraft.com/family.aspx?FamilyId=3121
I might buy one.
Tony

You can buy a drill press for £30

On Jun 30, 12:46 am, "George" wrote:
"tonyjeffs" wrote in message

...



On 28 Jun, 09:30, stuart noble wrote:
tonyjeffs wrote:
On 26 Jun, 09:13, MM wrote:
On Tue, 24 Jun 2008 21:05:02 -0700 (PDT), tonyjeffs

You can make a shooting block. You need a jack plane. That will get
you your right angle. Seehttp://tinyurl.com/58ldufandscrollup to
page 95 (this takes you to Google Books displaying The Practical
Woodworker).

MM

Thanks for all the suggestions. Some are so good that Im wondering
"Why couldn't I think of that?". I'm confident I can do it now. I'm
also inspired to make a drill guide to ensure my drill holes are
perpendicular; - an appropriately sized block of wood with a true hole
through it.

cheers
Tony

I've got a thing like a plunging router frame. Woolcraft I think. Not
expensive and comes in very handy once in a while. Letter boxes etc-
Hide quoted text -

- Show quoted text -

Stuart
An elderly guy in our street loaned me one of them many years ago.
Really good. I assumed it was one of those ideas that never took off
and was no longer available... But here it is:
http://www.woodcraft.com/family.aspx?FamilyId=3121
I might buy one.
Tony

You can buy a drill press for £30

What do you think
http://www.woodcraft.com/family.aspx?FamilyId=3121
is?

MBQ