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Sharpening my Japanese marking knife.
To mark a shoulder line around a piece of timber, even for a skilled craftsperson, takes time and patience. Using the
knife profile shown below, and my method of marking, takes the stress out of the equation, and gives me a very
successful method of marking shoulder lines around a piece of timber
To mark a shoulder line around a piece of timber, even for a skilled craftsperson, takes time and patience. Using the
knife profile shown below, and my method of marking, takes the stress out of the equation, and gives me a very
successful method of marking shoulder lines around a piece of timber
In this chapter, I will cover in detail, transforming the traditional style of Japanese marking knife into the design that I
use. This design is not original to me. I saw it in one of the many woodworking magazines I read. If I recall correctly the
person adapted the profile to make it suitable for a 'left handed' person.
Why a Japanese laminated marking knife?
Having attended the short Charlesworth cabinet making course, I became aware of the excellent quality of steel that
these tools were made from, and the results obtained from a finely tuned marking knife.
I also wanted a marking knife that would fit into one of my honing guides so that re sharpening was quick, and the
honing angles I found successful, were repeatable. In practice the knife fits comfortably into my Stanley honing guide.
Having said all that, any good quality knife is fine, but I would recommend on that fits into a honing guide, and, is made
from quality steel. What is key, is the angle and shape of the ‘front edge’ of the blade.
This image shows the front end of a Japanese marking knife, as new, and after it has been re-ground.
(my ref new and reground 012)
use. This design is not original to me. I saw it in one of the many woodworking magazines I read. If I recall correctly the
person adapted the profile to make it suitable for a 'left handed' person.
Why a Japanese laminated marking knife?
Having attended the short Charlesworth cabinet making course, I became aware of the excellent quality of steel that
these tools were made from, and the results obtained from a finely tuned marking knife.
I also wanted a marking knife that would fit into one of my honing guides so that re sharpening was quick, and the
honing angles I found successful, were repeatable. In practice the knife fits comfortably into my Stanley honing guide.
Having said all that, any good quality knife is fine, but I would recommend on that fits into a honing guide, and, is made
from quality steel. What is key, is the angle and shape of the ‘front edge’ of the blade.
This image shows the front end of a Japanese marking knife, as new, and after it has been re-ground.
(my ref new and reground 012)
and a close up
view. When
first ground I
would
recommend a
‘front edge’ of
between 3-4mm
(1/8”)
view. When
first ground I
would
recommend a
‘front edge’ of
between 3-4mm
(1/8”)
and as a guide I
would grind at an
angle or around 70
degrees.
would grind at an
angle or around 70
degrees.
(my ref new and reground 017)
web ref JMk05.JPG
and viewed from the top around 30
degrees. All of these angles can be
checked
using a sliding bevel.
web ref JMk05.JPG
and viewed from the top around 30
degrees. All of these angles can be
checked
using a sliding bevel.
and viewed from
the top around 30
degrees. All of
these angles can
be checked
using a sliding
bevel.
the top around 30
degrees. All of
these angles can
be checked
using a sliding
bevel.
I personally use a Tormek supergrind
water cooled machine, and I can
certainly
recommend it.
Having reground the knife to the
angles mentioned, the next job is to
flatten the back
of the blade so that we end up with a
mirror finish near the front end of the
knife.
This image shows the back of my
12mm wide Japanese marking knife
(my reference _MG_1414 copy)
web ref JMk06.JPG
water cooled machine, and I can
certainly
recommend it.
Having reground the knife to the
angles mentioned, the next job is to
flatten the back
of the blade so that we end up with a
mirror finish near the front end of the
knife.
This image shows the back of my
12mm wide Japanese marking knife
(my reference _MG_1414 copy)
web ref JMk06.JPG
I personally use a
Tormek supergrind
water cooled machine,
and I can certainly
recommend it.
Having reground the
knife to the angles
mentioned, the next job
is to flatten the back
of the blade so that we
end up with a mirror
finish near the front end
of the knife.
This image shows the
back of my 12mm wide
Japanese marking knife
Tormek supergrind
water cooled machine,
and I can certainly
recommend it.
Having reground the
knife to the angles
mentioned, the next job
is to flatten the back
of the blade so that we
end up with a mirror
finish near the front end
of the knife.
This image shows the
back of my 12mm wide
Japanese marking knife
Preparation the back of the blade.
I own two Japanese marking knives, one that is 12mm (1/2”) wide, and the other 9mm(3/8”). The first job after grinding
the front bevels, is to check if the back of the knife is flat.
For this purpose I use the side of my 150mm(6”) engineers try-square, having checked it with my Starrett two foot,
engineers straightedge. The 12mm knife was reasonably flat, whereas the 9mm(3/8”) was curving upwards, but only
slightly.
web ref JMk07.JPG
I own two Japanese marking knives, one that is 12mm (1/2”) wide, and the other 9mm(3/8”). The first job after grinding
the front bevels, is to check if the back of the knife is flat.
For this purpose I use the side of my 150mm(6”) engineers try-square, having checked it with my Starrett two foot,
engineers straightedge. The 12mm knife was reasonably flat, whereas the 9mm(3/8”) was curving upwards, but only
slightly.
web ref JMk07.JPG
This surface is then regularly used during the preparation of the back. I place the bottom of the marking
knife in contact with this surface with a light source behind.
During the preparation of the back of the blade I am aiming to form a CONCAVE SURFACE so
that I can see a glimmer of light around the centre point.
I have highlighted the above paragraph simply because it is the key in the process of preparing the back
of the blade.. It needs to be fractionally concave in the marking knifes length.
web ref JMk08.JPG
knife in contact with this surface with a light source behind.
During the preparation of the back of the blade I am aiming to form a CONCAVE SURFACE so
that I can see a glimmer of light around the centre point.
I have highlighted the above paragraph simply because it is the key in the process of preparing the back
of the blade.. It needs to be fractionally concave in the marking knifes length.
web ref JMk08.JPG
With the 800 grit
stone wedged in
the sharpening
station, I use the
1200 grit stone to
form a slurry, then
I add a pencil line,
as shown below.
This will act as a
guide during the
sharpening
process
stone wedged in
the sharpening
station, I use the
1200 grit stone to
form a slurry, then
I add a pencil line,
as shown below.
This will act as a
guide during the
sharpening
process
then position the
marking knife so that
it is around 15mm
(5/8”) over the edge
of the
stone.
marking knife so that
it is around 15mm
(5/8”) over the edge
of the
stone.
then position the marking knife so that
it is around 15mm (5/8”) over the
edge of the
stone.
(my reference flattening the bottom
M1 015)
web ref JMk11.JPG
it is around 15mm (5/8”) over the
edge of the
stone.
(my reference flattening the bottom
M1 015)
web ref JMk11.JPG
Charlesworth describes this a
movement 1.
(my reference movement 1 020)
web ref JMk12.JPG
movement 1.
(my reference movement 1 020)
web ref JMk12.JPG
Charlesworth
describes this a
movement 1.
describes this a
movement 1.
And the chisel is moved in the direction shown, back and forth along the stone. I add firm finger pressure with two
fingers from my left hand, and lightly hold the knife with my right hand. After a period of time the two fingers on the left
hand became a little uncomfortable, to I use my thumb instead.
Charlesworth recommends that the point of the tool is off the stone for around 50% of the time. Using this method,
forms a fraction of a hollow in the knife’s length, which is a desirable characteristic. The reason why, will become clear
later in this chapter.
fingers from my left hand, and lightly hold the knife with my right hand. After a period of time the two fingers on the left
hand became a little uncomfortable, to I use my thumb instead.
Charlesworth recommends that the point of the tool is off the stone for around 50% of the time. Using this method,
forms a fraction of a hollow in the knife’s length, which is a desirable characteristic. The reason why, will become clear
later in this chapter.
An important note on water stone
maintenance
After 50 strokes forwards and
backwards in the direction indicated,
Charlesworth recommends that you
stop using that edge, rotate the stone
180* and use the opposite edge.
(my reference honing 30)
web ref JMk13.JPG
maintenance
After 50 strokes forwards and
backwards in the direction indicated,
Charlesworth recommends that you
stop using that edge, rotate the stone
180* and use the opposite edge.
(my reference honing 30)
web ref JMk13.JPG
An important note
on water stone
maintenance
After 50 strokes
forwards and
backwards in the
direction indicated,
Charlesworth
recommends that
you stop using that
edge, rotate the
stone 180* and
use the opposite
edge.
on water stone
maintenance
After 50 strokes
forwards and
backwards in the
direction indicated,
Charlesworth
recommends that
you stop using that
edge, rotate the
stone 180* and
use the opposite
edge.
In practice I find that after maybe 15 forward and backwards strokes, the water stone becomes clogged, and it is
difficult to move up and down the stone. In this case I use the 1200 grit stone, re form a slurry. You just need to
remember how many more strokes up and down the stone you can take.
Note on water stone maintenance.
After 50 forward and backwards strokes on both edges, the stone now requires flattening.
A representation of what happens with a Japanese water stone after it has been used in this manner.
It does not take long at all before the Japanese waters stones start wearing, and if not flattened as described in
the chapter , ‘water stone maintenance’, the tool being sharpened will be useless.
The image below represents a stone that has had the grid marks pencilled in, and has been rubbed maybe half a
dozen times on the wet and dry paper during the flattening process. The pink section of the stone represents the
flattened area, whilst the area with the grid marks still showing represent the area that has been worn away.
(my reference 12mm chisels-flattening the bottom M2, 024g)
web ref JMk14.JPG
difficult to move up and down the stone. In this case I use the 1200 grit stone, re form a slurry. You just need to
remember how many more strokes up and down the stone you can take.
Note on water stone maintenance.
After 50 forward and backwards strokes on both edges, the stone now requires flattening.
A representation of what happens with a Japanese water stone after it has been used in this manner.
It does not take long at all before the Japanese waters stones start wearing, and if not flattened as described in
the chapter , ‘water stone maintenance’, the tool being sharpened will be useless.
The image below represents a stone that has had the grid marks pencilled in, and has been rubbed maybe half a
dozen times on the wet and dry paper during the flattening process. The pink section of the stone represents the
flattened area, whilst the area with the grid marks still showing represent the area that has been worn away.
(my reference 12mm chisels-flattening the bottom M2, 024g)
web ref JMk14.JPG
This series of images shows the back of a Japanese marking knife during the various stages of preparation.
These images were taken whilst flattening the back of a knife on ‘wet and dry’ paper, not my water stones, simply
because the scratches were easier to see and photograph.
A hollow can be seen in the back of the blade, which is a common feature with the Japanese marking knife. It
generally makes flattening the backs so much quicker.
Image 1.
After a small amount of work the outer edges of knife are being flattened. The untouched area is hollow.
web ref JMk15.JPG
These images were taken whilst flattening the back of a knife on ‘wet and dry’ paper, not my water stones, simply
because the scratches were easier to see and photograph.
A hollow can be seen in the back of the blade, which is a common feature with the Japanese marking knife. It
generally makes flattening the backs so much quicker.
Image 1.
After a small amount of work the outer edges of knife are being flattened. The untouched area is hollow.
web ref JMk15.JPG
Image 2
A fair amount of work has been carried out, but area near to the point of the blade has still not been flattened.
web ref JMk16.JPG
A fair amount of work has been carried out, but area near to the point of the blade has still not been flattened.
web ref JMk16.JPG
Image 3
And in this image the scratch marks are right up to the tip of the blade. Using the side of my 150mm(6”)
engineers try-square, I check that the area that has been worked on is fractionally concave. Using the
method of only having the knife on the stone for 50% of the time has always worked for me. You may just be
able to see a fraction of light because a hollow has been formed, but I have never seen that much, just a
glimmer, and that is what I am aiming for.
web ref JMk17.JPG
And in this image the scratch marks are right up to the tip of the blade. Using the side of my 150mm(6”)
engineers try-square, I check that the area that has been worked on is fractionally concave. Using the
method of only having the knife on the stone for 50% of the time has always worked for me. You may just be
able to see a fraction of light because a hollow has been formed, but I have never seen that much, just a
glimmer, and that is what I am aiming for.
web ref JMk17.JPG
Movement 2.
and then the knife is moved as illustrated. Add finger pressure to keep the blade
firmly on the stone. The whole objective of this exercise is to replace the scratch
marks that were at right angles to the blade, to scratch marks that are roughly
parallel to the length of the blade. If the blade has been given that fractionally hollow
surface in its length , then you may only need maybe 50 forward and backwards
strokes before you have the parallel scratch marks.
In the image below I have illustrated 21 forward and 21 backwards movements. In
reality you should managed around 80-100.
(my reference honing 21)
web ref JMk18.JPG
and then the knife is moved as illustrated. Add finger pressure to keep the blade
firmly on the stone. The whole objective of this exercise is to replace the scratch
marks that were at right angles to the blade, to scratch marks that are roughly
parallel to the length of the blade. If the blade has been given that fractionally hollow
surface in its length , then you may only need maybe 50 forward and backwards
strokes before you have the parallel scratch marks.
In the image below I have illustrated 21 forward and 21 backwards movements. In
reality you should managed around 80-100.
(my reference honing 21)
web ref JMk18.JPG
Using firm pressure
on the knife, travel
along the full length
of the stone.
on the knife, travel
along the full length
of the stone.
and then back again
for another 80-100
strokes.
for another 80-100
strokes.
The 1200 grit water stone.
The next job is to replace the 800 grit scratch marks with 1200 grit scratch marks using the same method,
movement 1 followed by movement 2, remembering to keep the knife off the stone for 50% of the time.
The 8000 grit water stone.
The final part of the flattening process is to repeat the whole process again using the 8000 grit stone
ending up with a mirror like finish on the back, in particular right at the point of the blade.
web ref JMk06.JPG
The next job is to replace the 800 grit scratch marks with 1200 grit scratch marks using the same method,
movement 1 followed by movement 2, remembering to keep the knife off the stone for 50% of the time.
The 8000 grit water stone.
The final part of the flattening process is to repeat the whole process again using the 8000 grit stone
ending up with a mirror like finish on the back, in particular right at the point of the blade.
web ref JMk06.JPG
Honing angles.
The next part of the process is preparing the ‘front edge’ and point of the knife, and for this I use my Stanley honing
guide, with the blade projecting 11mm from the end of the guide, giving a honing angle of 35 degrees.
The first honing is carried out on my 800 grit stone. Position the blade as indicated below, and only move the blade in
one direction as indicated by the arrow. By positioning a table lamp close to my sharpening station, I can clearly see a
small wire edge being formed, and it needs to be formed across the complete width of the ‘‘front edge’’. A dark deposit
of metal is also left on the stone. You may have to slightly reposition the blade to ensure that the full, ‘‘front edge’ is
being honed.
I then clean the blade and the honing guide removing all the residue from them both.
I reset the projection in the Stanley honing guide to 9.5mm, and repeat the process on the 8000 grit water stone.
(my reference my sharpening station 099)
web ref JMk22.JPG
The next part of the process is preparing the ‘front edge’ and point of the knife, and for this I use my Stanley honing
guide, with the blade projecting 11mm from the end of the guide, giving a honing angle of 35 degrees.
The first honing is carried out on my 800 grit stone. Position the blade as indicated below, and only move the blade in
one direction as indicated by the arrow. By positioning a table lamp close to my sharpening station, I can clearly see a
small wire edge being formed, and it needs to be formed across the complete width of the ‘‘front edge’’. A dark deposit
of metal is also left on the stone. You may have to slightly reposition the blade to ensure that the full, ‘‘front edge’ is
being honed.
I then clean the blade and the honing guide removing all the residue from them both.
I reset the projection in the Stanley honing guide to 9.5mm, and repeat the process on the 8000 grit water stone.
(my reference my sharpening station 099)
web ref JMk22.JPG
The final part of the sharpening process is to remove the wire edge that has been formed by the honing process. I
never found any need to work on the bottom edge of the Japanese marking knives, because they arrived razor
blade sharp straight from the manufacturer.
Removing the wire edge.
Now this is where it is so handy having a blade that is fractionally hollow in its length, and continually maintaining that
feature.
I position the 8000 grit stone in the sharpening station, form a slurry with the nagura stone, and move the knife as
illustrated below, with the tip of the blade around 15mm(5/8”) off the stone, and it always stays off the stone. I will
move the knife around half a dozen strokes up and down the stone whilst in this position. I do this to maintain that
fraction of a hollow in the knife’s length. I will refer to this as movement 1a
(my reference movement 1 023)
web ref JMk23.JPG
never found any need to work on the bottom edge of the Japanese marking knives, because they arrived razor
blade sharp straight from the manufacturer.
Removing the wire edge.
Now this is where it is so handy having a blade that is fractionally hollow in its length, and continually maintaining that
feature.
I position the 8000 grit stone in the sharpening station, form a slurry with the nagura stone, and move the knife as
illustrated below, with the tip of the blade around 15mm(5/8”) off the stone, and it always stays off the stone. I will
move the knife around half a dozen strokes up and down the stone whilst in this position. I do this to maintain that
fraction of a hollow in the knife’s length. I will refer to this as movement 1a
(my reference movement 1 023)
web ref JMk23.JPG
Then its back to movement 2 on the 8000 grit stone. You may have to re form a slurry. Probably a dozen on and off
strokes on this stone, and that wire edge drops off. I then clean the knife, oil it, then wipe the oil off.
(my reference honing 21)
web ref JMk24.JPG
strokes on this stone, and that wire edge drops off. I then clean the knife, oil it, then wipe the oil off.
(my reference honing 21)
web ref JMk24.JPG
Summary.
I just want to highlight a few points that I believe are important.
a select a knife that will allow you to hone it in a honing guide.
b Maintain that fractionally hollow back so that sharpening the tip of the blade is
easy.
c Stick to the guidelines with regards to how often you flatten your water stones.
Japanese marking knife. projections from the various machines/guides.
Tormek grindstone 40mm
Stanley honing guide 11mm
Stanley honing guide 9.5mm
I just want to highlight a few points that I believe are important.
a select a knife that will allow you to hone it in a honing guide.
b Maintain that fractionally hollow back so that sharpening the tip of the blade is
easy.
c Stick to the guidelines with regards to how often you flatten your water stones.
Japanese marking knife. projections from the various machines/guides.
Tormek grindstone 40mm
Stanley honing guide 11mm
Stanley honing guide 9.5mm
In September 07 I had my first trip to France and visited a local museum. Here are some photos of knives that were
used hundreds of years ago for cutting leather.
What was interesting to me was the fact that the blades had a hollow back section, and the cutting point had been
ground away in a similar manner to the one that I now use.
In this image you can see a selection of tool used by ‘Le Cordonnier’
web ref JMk25.JPG
used hundreds of years ago for cutting leather.
What was interesting to me was the fact that the blades had a hollow back section, and the cutting point had been
ground away in a similar manner to the one that I now use.
In this image you can see a selection of tool used by ‘Le Cordonnier’
web ref JMk25.JPG
and a close up
view
view
web ref JMk26.JPG
Update November 07
On checking the Axminster tools catalogue I notice that they now supply a 'V' shaped Japanese marking knife and I
was interested to see if this knife worked as well as the one that I had remodelled. I am pleased to say that it does,
but it will still require the same amount of work on the back of the knife to get that ‘fractionally concave surface’
along the length of the knife, and a mirror like finish on my 8000 grit water stone.
web ref JMk27.JPG
On checking the Axminster tools catalogue I notice that they now supply a 'V' shaped Japanese marking knife and I
was interested to see if this knife worked as well as the one that I had remodelled. I am pleased to say that it does,
but it will still require the same amount of work on the back of the knife to get that ‘fractionally concave surface’
along the length of the knife, and a mirror like finish on my 8000 grit water stone.
web ref JMk27.JPG
One of the great advantages of this design is that it is suitable for a left or right handed person, in addition, it fits
comfortably in my Stanley honing guide allowing for speedy accurate and repeatable honing angles.
Just like the model that I reground, the back of the knife is partly hollow and only has a small amount of useable
blade at the front end. From these two images you will see that the knife was not suitable for use right out of the
packet because of a slight chip at the tip.
To remove the chip at the 'front edge' I reground the knife keeping the same profile.
web ref JMk28.JPG
comfortably in my Stanley honing guide allowing for speedy accurate and repeatable honing angles.
Just like the model that I reground, the back of the knife is partly hollow and only has a small amount of useable
blade at the front end. From these two images you will see that the knife was not suitable for use right out of the
packet because of a slight chip at the tip.
To remove the chip at the 'front edge' I reground the knife keeping the same profile.
web ref JMk28.JPG
As before the back of the blade needs checking on the engineers try-square. In this case I found that the blade
rocked a little on the side of the square.
So I repeated the whole process of preparing the back of the blade as previously described to increase the useable
area at the cutting edge to around 30mm(1 ¼”)
web ref JMk29.JPG
rocked a little on the side of the square.
So I repeated the whole process of preparing the back of the blade as previously described to increase the useable
area at the cutting edge to around 30mm(1 ¼”)
web ref JMk29.JPG
and polished it to
near mirror like
finish.
With regular
sharpening and
removal of the
‘wire edge’ on the
8000 grit water
stone, this surface
really does end up
mirror like.
near mirror like
finish.
With regular
sharpening and
removal of the
‘wire edge’ on the
8000 grit water
stone, this surface
really does end up
mirror like.
Using the same
projections from
my Stanley honing
guide the blade
was honed giving a
razor sharp edge.
projections from
my Stanley honing
guide the blade
was honed giving a
razor sharp edge.
I have recently purchased some Ron Hock marking knives. They are excellent blades, but do not have the
hollowed out back design of the Japanese knife.
They are made from beautiful high speed steel and work just as well as the Japanese knife, but without having
to dedicate a considerable amount of time to remove the hollowed back.
It is the tool I would certainly recommend to my students simply because you will not be spending so much time
getting it ready for work.
hollowed out back design of the Japanese knife.
They are made from beautiful high speed steel and work just as well as the Japanese knife, but without having
to dedicate a considerable amount of time to remove the hollowed back.
It is the tool I would certainly recommend to my students simply because you will not be spending so much time
getting it ready for work.
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The Alzheimers Association. www.justgiving.com/hand-cut-dovetails
Water aid www.justgiving.com/hand-cut-dovetails1
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Help for heroes www.justgiving.com/hand-cut-dovetails3
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choice.
The Alzheimers Association. www.justgiving.com/hand-cut-dovetails
Water aid www.justgiving.com/hand-cut-dovetails1
Dreams come true www.justgiving.com/hand-cut-dovetails2
Help for heroes www.justgiving.com/hand-cut-dovetails3
The Wounded Warrior Project www.firstgiving.com/fundraiser/hand-cut-dovetails/alan