plane-art - 8/30/94
"Reconstruction and Use of a Saxon Plane" by Tom Perigrin.
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Mark S. Harris AKA: THLord Stefan li Rous
Stefan at florilegium.org
From: tip at lead.tmc.edu (Tom Perigrin)
Subject: Reconstructing a Saxon Plane
Date: 29 Aug 1994 08:21:21 GMT
Organization: A.I. Chem Lab, University of Arizona
So, while half the Knowne World was off at Pennsic, some of us were beavering
away in our humble persuits closer to our homes... and from that, I
submit a small report of "what I did over Pennsic Vacation"...
Reconstruction and Use of a Saxon Plane
The shape of the wood plane has changed dramatically throughout
history. It is therefor instructive to construct and use planes of different
periods to get a better feel for the evolution of this most important
woodworking tool. The Maidstone Museum has a particularly interesting
example of a Saxon plane found in Sarre, Kent, which dates from around the
eighth century CE. The plane is especially interesting as one side was lost
before or during it's burial, which gives a good look into the construction
techniques. A side view photograph can be found in W. L. Goodman's
book, "The History of Woodworking Tools". By using this side view photo
and the measurements given in the text one can attempt to make a
reconstruction of the plane.
The plane is made of several types materials fastened together: The
body of the plane is 5 3/8" long, 1 1/4" wide, and 1 1/4" high, and is made
from horn. There is a bronze sole which is 1/8" thick, 6" long, and 1 1/4"
wide, which is attached to the body by three iron rivets. The rivets pass
through and and are peened over three small bronze plates let into the upper
surface of the body. There is a small grip hollowed out behind the blade, and
the side elevation of this grip can be determined from the photograph. The
plane of this grip cannot be deteremined from the photo. However, the text
indicates that it is similar to three planes shown elsewhere in the book that
show that the handle of the grip is probably narrower than the body of the
plane. The bed for the blade was at an angle of 43 degrees, which is very
close to the modern angle of 45 degrees and much less than the common
Roman angle of 50 degrees. The blade and the pin holding the wedge are
lost, but there are Roman and Frisian examples that lead us to believe that
the blade was thickness tapered, and that it was held by a wedge held behind a
transverse pin. The exact location of the pin cannot be determined since both
sides of the plane are damaged or missing around the expected location of the
I used a computer scanner to input the picture of the plane, and then
superimposed a 1/8" grid over it to obtain a set of measurements. I also
decided to make the plane 1/4" wider than the original, because I had greater
need for a wider plane than for a narrow one.
One of the problems in reconstructing the Sarre plane is that the body
is made from horn. It seems that bone or horn are the most common materials
used to make planes that have survived from this period. At this time I have
not found sources of bone or horn in sufficiently large pieces to reconstruct
the plane, so I decided to make the body from one of the commonly used tool
making woods - hard maple. I utilized my grid of 1/8" points to carefully
mark out the length and shape of the body. I used a small scroll saw to cut
out the shape, and threaded the blade through a 1/4" hole and cut out the grip.
A series of four 1/4" holes were drilled into the body at a 45 degree angle to
help define the bed, and another four holes were drilled vertically to form
the front of the mouth. The rest of the wood was removed by hand chiseling,
and a home-made plane float was used to refine the 45 degree bed to an angle of
about 43 degrees. The rear grip was shaped using a 1/4" drill to make some
preliminary guide holes, and then with carving gouges and a set of riffler
Although a bronze sole was used in the original, it was impossible to
obtain sheet bronze without ordering it at a rather steep price. Since I had a
sheet of 1/8" thick brass on hand, the sole was cut from the larger piece of
1/8" thick brass with a hack saw, and then filed into shape. The front and
tail ends of the sole were bent by grasping the main part of the sole in a vice
and a rawhide mallet was used to give a 10 degree sharp bend to the front end
and a 5 degree bend to the rear end. A series of 1/8" holes were used to
define the shape of the mouth, which was then filed square, and further
refined to a bedding angle of 43 degrees and a front angle of 80 degrees
using a set of escapement files. Three holes were drilled for 1/8" rivets,
and a conical depression was made for the head of each rivet using a larger
drill. A 1/8" hole was then drilled through the maple stock for each rivet.
At the point of exit of each rivet a small brass plate (1/2" square in the
front and middle, and 3/8" by 1/2" for the plate on the grip) was inlayed,
and the hole drilled through the plate. Soft iron rod with a diameter of
1/8" inch was then placed in a large iron plate with holes similar to the
brass plate, and the head of each rivet was formed by hammering. The
rod was inserted through the body of the plane, and cut off about 1/8"
above the level of the brass inlayed plate. The rod was then peened over,
affixing the sole to the maple body.
The blade was made from a "New Britain" 10" bastard file. A coal
forge was used to hot cut a 4" section of the file. The section was hammered
into a taper, diminishing from about 3/16" thick at the front to about 1/8"
thick at the rear. The blank was annealed, and the residual file-tooth marks
were removed and the 35 cutting edge was formed by rough grinding. The blade
was heated to a bright red heat, and quenched in used motor oil. The blade
was tempered by cleaning the surfaces to see oxidation colors, followed by
heating high above the coals until a light blue color was observed, followed
by rapid quenching in water. The blade was then finish ground on a white 80
grit grinding wheel and a 200 grit wet stone, and sharpened on a series of
oil stones and finally honed on a leather strop.
Since the sides of the Sarre plane are broken at the expected location
on the holding pin, the location was determined to provide optimum holding
power and minimal chance of splitting the cheeks. The pin was located by
laying the blade on the side of the plane in the correct location, adding a
rough-out of the wedge, and then locating the pin at a position that would hold
the wedge and which was halfway between the top and the bottom on the
body. A 1/8" brass pin was used. The hole in the right cheek was drilled
with a 1/8" bit, but the hole in the left cheek was drilled a little undersize
(0.110"), and about 1/4" of the pin was tapered by filing. The overlong pin
was tapped through the right hand side, and into the left cheek until a snug
fit was obtained. The protruding bits were removed with a jewelers saw and
touched up with a file.
The wedge was then made from hard maple. The angle chosen was
one in ten, and the thickness chosen so that the front of the wedge would rest
about 1/8" behind the cutting edge when tapped home. This was done to test
a theory about "chip breakers" described below. An alternative wedge that
had a steeper angle and which stopped 1/2" short of the cutting edge was also
The plane was finished with a mixture of beeswax, linseed oil, and
It was with trepidation and excitement that I fixed a 15" long 1"
square of rough cut pine in my tail vice, and picked up my new plane.
Although I found the blade adjustments to be fiddly, that is generally true of
any plane until one gains familiarity with it's quirks and peculiarities. The
first shavings were good, but a little too coarse... However, within a few
minutes I was taking off full length paper thin spills that compared favorably
with those produced by any modern Stanley. The surface which is left behind
is very good, and compares or beats most of my modern planes.
The grip is still "funny". I can't get a finger _through_ the grip, and
so I end up using my thumb on the left side pointing forward, and either my
first or second finger on the other side pointing backwards. If I use the
second finger my first finger tends to curl over the top of the iron - this
doesn't seem to add power but somehow it does seem to feel right. I note
that this grip seems very "ergonometric". The hand and wrist are lined up
and the first finger points the way to go. The left hand can press down on
the nose of the plane, and help guide it. Although the plane is surprisingly
hefty for a wooden bodied plane of it's size (with a 1/8" thick brass sole and
a very thick blade), the thumb and finger can easily lift and control the
Once I had some degree of familiarity with the plane I decided to test
my theory about chip breakers. The modern double iron with it's built in
chipbreaker is a modern invention... it was invented in the early 1800's or
so. Yet I had often wondered if a close fitting wedge might serve some of the
function of a chip breaker. In that case, the advent of an integral chipbreaker
in a wooden bench plane would not be a signal improvement on the quality of
the finish that was possible, but would rather be an improvement in that the
wedge would not have to be fitted as precisely as before. The first wedge
made was designed to fit snugly when it's tip was about 1/8" behind the
cutting edge. In addition, the wedge had a small 45 degree "cutting edge" to
act as a chip breaker. The shavings and surfaces produced with this blade and
wedge combination were excellent. I removed this wedge and replaced it with
a wedge that had a slightly steeper angle, and which reached only to within
1/2" of the cutting edge. This wedge also had the 45 degree "cutting edge",
but the bevel was longer. The rest of the mouth geometry was not changed.
There was a dramatic change in the performance of the plane. The shavings
tended to clog the gullet of the plane, and had to be picked out with a splint
of wood. The shavings were not long curling spills anymore, but were
broken accordions of wood. Although I suspected that I could detect a
difference in the quality of the surface, it was not so significant that I
couldn't be sure I wasn't fooling myself. I'll have to have a third party
do a blind test on the relative smoothness of two surfaces obtained by
planing with the two wedges.
So, more testing needs to be done. Not only do I have to test how
changing wedges affects the surfaces obtained, it will also be interesting to
see how well the plane holds up to use, abuse, etc... I am interested to see
if people with smaller fingers (I have large hands) can hold the plane in a
different and more efficient fashion. However, since I have just obtained a
set of measured drawings of some of the tools recovered from the Mary Rose
(sunk mid-1500's), I think my next project might be a brace and bit or a
long try plane from that period.