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.
Japknifetip002copy.jpg
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.
Japknifetip002copy.jpg
and a close up view. When first ground I would recommend a ‘front edge’ of between 3-4mm(1/8”)
my ref new and reground 013)
my ref new and reground 013)
and as a guide I would grind at an angle or around 70 degrees.
(my ref new and reground 016)
(my ref new and reground 016)
and viewed from the top around 30 degrees. All of these angles can be checked using a sliding bevel.
(my ref new and reground 017)
(my ref new and reground 017)
Flattening 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.
honing 019
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.
honing 019
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
Japanese marking knife, honing 16
line, as shown below. This will act as a guide during the sharpening process
Japanese marking knife, honing 16
then position the marking knife so that it is around 15mm (5/8”) over the edge of the stone.
flattening the bottom M1 015
flattening the bottom M1 015
Charlesworth describes this a movement 1.
movement 1 020
movement 1 020
And the knife 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, so 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, I would recommend that you stop using that edge,
rotate the stone 180* and use the opposite edge.
honing 30
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, so 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, I would recommend that you stop using that edge,
rotate the stone 180* and use the opposite edge.
honing 30
Like so.
honing 032
honing 032
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.
Japknife004copy.
A fair amount of work has been carried out, but area near to the point of the blade has still not been flattened.
Japknife004copy.
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 flat. 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.
japknife006copy
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 flat. 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.
japknife006copy
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.
honing 21
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.
honing 21
| Using firm pressure on the knife, travel along the full length of the stone. honing 027 |
| and then back again for another 80-100 strokes. honing 028 |
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.
japknife005copy
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.
japknife005copy
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 4mm 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.
I reset the projection in the Stanley honing guide to 3mm, and repeat the process on the 8000 grit water stone.
my sharpening station 099
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 4mm 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.
I reset the projection in the Stanley honing guide to 3mm, and repeat the process on the 8000 grit water stone.
my sharpening station 099
The final part of the sharpening process is to remove the wire edge that has been formed by the honing process. I
never found the 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 ref movement 1 023
never found the 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 ref movement 1 023
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.
honing 21
strokes on this stone, and that wire edge drops off. I then clean the knife, oil it, then wipe the oil off.
honing 21
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.
Movement 1
movement 1 020
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.
Movement 1
movement 1 020
Movement 1a, where the blade stays off the stone. I use this only on the 8000 grit stone when removing the wire
edge.
my ref movement 1 023
edge.
my ref movement 1 023
Movement 2
honing 027
honing 027
Japanese marking knife.
The Projections from the various machines/guides.
Tormek grindstone 26mm 30degrees.
Stanley honing guide 4mm 35degrees
Stanley honing guide 3mm 38 degrees?
The Projections from the various machines/guides.
Tormek grindstone 26mm 30degrees.
Stanley honing guide 4mm 35degrees
Stanley honing guide 3mm 38 degrees?
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)
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 to 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.
12mm chisels-flattening the bottom M2, 024g
difficult to move up and down the stone. In this case I use the 1200 grit stone to 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.
12mm chisels-flattening the bottom M2, 024g
This series of images shows the back of a Japanese marking knife during the flattening process. 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, and they removed the metal much quicker than the 800 grit stone.
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.
Japknife003copy
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, and they removed the metal much quicker than the 800 grit stone.
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.
Japknife003copy
I personally use a Tormek 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 9mm(3/8")wide Japanese marking knife
Japknife05copy.jpg
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 9mm(3/8")wide Japanese marking knife
Japknife05copy.jpg
 | |  | |  | |  | |  | |  |
and a view of the back of my larger Japanese marking knife. The hollowed the back is still visible. What I would like to
highlight, is the fact that it is the 'front edge' and the tip of the blade, that you need to concentrate on, during the
sharping process.
highlight, is the fact that it is the 'front edge' and the tip of the blade, that you need to concentrate on, during the
sharping process.
Update 1st October 07
On checking the Axminster tools catalogue I notice that they now supply a 'V' shaped Japanese marking knife. I would
imagine that this knife will allow you to successfully mark a shoulder line using my methods. I have explained this under
the heading Marking a shoulder line
On checking the Axminster tools catalogue I notice that they now supply a 'V' shaped Japanese marking knife. I would
imagine that this knife will allow you to successfully mark a shoulder line using my methods. I have explained this under
the heading Marking a shoulder line
Whilst on holiday in France during September, I came across the following display in a museum. The first image shows
the tools used by a cobbler hundreds of years ago.
the tools used by a cobbler hundreds of years ago.
And this shot shows a close up view of five knives used by those craftspeople. I was interested to see that the back of
the blade was hollow, and the front end of the knife is shaped in a very similar manner to my marking knife.
Fortunately for me I was allowed to photograph the exhibit, something that is not always possible in this country.
the blade was hollow, and the front end of the knife is shaped in a very similar manner to my marking knife.
Fortunately for me I was allowed to photograph the exhibit, something that is not always possible in this country.
