cb

charlie b

30/03/2006 12:20 AM

Enoch Root Inspired Back Saw Handle Angles to ab.b.p.w.

Did'ja ever wonder what the average handle angle on a backsaw
was? Enoch Root mentioned Bob Brode's web pages on various
handle shapes and, being a data freak, I measured the angles
of the handle examples on Brode's pages and posted Open
Hanlde and Closed Handle data and results in a.b.p.w. for
anyone who likes obscure woodworking stuff. (I'll do almost
anything to avoid doing my taxes)

charlie b


This topic has 3 replies

cb

charlie b

in reply to charlie b on 30/03/2006 12:20 AM

30/03/2006 8:23 AM

Oleg Lego wrote:
>
> Interesting. Do you have any thoughts on why the average angles of
> open vs. closed handles are so different?

That one's got me wondering too. The pictures don't show
the whole saw, just a bit of the blade and all of the handle.
Most, but not all, of the closed handle backsaws appear to
be tenon saws while most, but not all, of the open handle
backsaws appear to be dovetail saws. Could be that the
wider blade of the tenon saw raises the handle more above
the top of the cut and that the rip cut is much longer than
those of a typical dovetail.

I suspect it also has to do with how the cut is made. With
a dovetail saw, the part is held vertically in the vise and
the cuts are made basically straight down, with the teeth
horizontal. With a tenon, the part is often tilted and the
cut s made with the blade at an angle to the long axis of
the part then turned around for the next cut and finished
off with horizontal cuts - an inverted "V" This gets you
more of the saw in the cut so the cut guides the saw once
you get started. Imagine cutting a 1" thick board. If
you cut directly acrossed it, you never have more than
one inch of contact between the sides of the blade and the
wood. But if you cut at 45 degrees you've got 1.414
inches of contact. More side friction and more force
or more strokes required, but staighter cut.

1"
____ dovetail cut made horizontal

/ \ 1"
/ 1.414" 1.414" \ _____
cut 1 angle cut 2 angle finish cut

Then again, it could be the personal preference of
the first guy and everyone else thouth "well if it's
good enough for him . . ."

The longer rip and cross cut saws all had closed handles
and the handle angle looked closer to 90 degrees. With those
saws the user is typically sawing almost straight down.

It is interesting that the handle of "western" saws
dictate how you can use the saw - it's fixed more
or less and the part must be oriented properly to
make the cut. With a japanese saw like a dozuki,
you can go from a horizontal cut to a vertical cut
in a smooth, continous motion without having to
reorient the board. Imagine cutting an inch and a
half notch in the corner of a wide panel. The best
part orientation would be flat on the bench and
the cut started almost horizontal and then switched
to vertical once started. But with a western saw
you either have to kneel on the horizontal panel
and saw leaning over the cut or try, in spite of
the handle, to cut vertically.

I like the Japanese pull saws - more options -
and having options is always good.

charlie b

OL

Oleg Lego

in reply to charlie b on 30/03/2006 12:20 AM

30/03/2006 7:41 AM

The charlie b entity posted thusly:

>Did'ja ever wonder what the average handle angle on a backsaw
>was? Enoch Root mentioned Bob Brode's web pages on various
>handle shapes and, being a data freak, I measured the angles
>of the handle examples on Brode's pages and posted Open
>Hanlde and Closed Handle data and results in a.b.p.w. for
>anyone who likes obscure woodworking stuff. (I'll do almost
>anything to avoid doing my taxes)

Interesting. Do you have any thoughts on why the average angles of
open vs. closed handles are so different?

ER

Enoch Root

in reply to charlie b on 30/03/2006 12:20 AM

30/03/2006 8:08 AM

Oleg Lego wrote:
> The charlie b entity posted thusly:
>
>
>>Did'ja ever wonder what the average handle angle on a backsaw
>>was? Enoch Root mentioned Bob Brode's web pages on various
>>handle shapes and, being a data freak, I measured the angles
>>of the handle examples on Brode's pages and posted Open
>>Hanlde and Closed Handle data and results in a.b.p.w. for
>>anyone who likes obscure woodworking stuff. (I'll do almost
>>anything to avoid doing my taxes)
>
>
> Interesting. Do you have any thoughts on why the average angles of
> open vs. closed handles are so different?

I think the handle angles are smaller on the "finer" saws... finer in
the sense of 15pt vs. 10pt.

Rational: you're going to be hanging over your workpiece more as you
saw if you are cutting a narrow dovetail, paying attention to the cut on
both sides and how straight the blade is. With a bigger job and a
longer (tenon) saw you're wanting to get more behind it for a more
effective push. Being more on top of the saw it feels less awkward if
your hand is tipped up to grasp the saw than if you had to grab the saw
from behind at a lower position and angle.

aside: I noticed on an old panel saw (an early Jackson) I have, that if
I rotate my wrist with the saw in hand the axis of rotation of the saw
blade is very nearly colinear with the teeth of the blade. It's a small
saw (~18" blade) and this doesn't work for a larger D8, though, so it
may be a coinkidink.

er
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