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Japanese sen zogan or wire inlay tutorial

Guest ford hallam

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Guest ford hallam

This is a series of close up views showing the process of Japanese Sen-zogan, or wire inlay.



Step 1Here I have chiselled a “V” shaped groove into a mild steel plate. I used the corresponding chisel seen in the image. The groove is cut so that the width matches the diameter of the wire I want to inlay. The wire is fine, or pure, silver. The other chisel in this image is a shishiai-bori chisel; it’s useful in this instance for cutting the spiral of steel away cleanly.

The silver wire is annealed and the steel rule in the corner of the image is marked in millimetres to give a sense of scale. There is actually a more efficient technique that would be more appropriate for inlaying wire of this thickness, and particularly for straight lines. I wanted to follow this particular method though, using thicker wire than I’d usually use, so that you’d be better able to see how it works. The other technique I mentioned will be the subject of another tutorial at some time.



Step 2

Now, using a flat chisel, I’m pushing the inner face of the groove vertical. With the chisel at this angle, I placed the tip in the base of the “V” groove and tap the chisel so that it moves down and toward the edge. I’m not really trying to undercut the groove in this instance. Forcing the sides vertical like this also creates a slightly raised edge to the groove. When doing this be careful not to damage the opposite edge of the groove.



Step 3

With both sides of the groove forced up, and outward, this view shows the wire in position prior to being tapped into the prepared channel. You’ll notice that the wire is slightly wider than the groove. It’s generally better to have too much metal to force into the channel than too little, as that would result in ugly gaps in the finished inlay. The tool seen here is a flat bottomed punch which I’ll use to work the wire into place. It has a lightly textured face to prevent any unwanted slipping. These punches, used like this, are called narashi-tagane in Japanese workshops. This texture can be applied simply by tapping the face of the punch with a coarse file. Once the first side is completed do the same thing to the other side.



Step 4

I’ve begun to work the silver wire into the channel here. You’ll notice the excess material has spread over the edges of the groove. As I’m tapping the punch down onto the silver it is being forced into all the tiny crevices in the bottom of the channel, there may be a sleight undercut but I’m not relying on that. As I tap down on the silver the raised edges of the steel are also being pushed down and inward. This is what actually holds the wire in place. It is really important that the wire you’re intending to inlay be in its softest state, that way it tends to stick quite well in the first few taps as you gently work the metal in place. It’s important to start from one end and move steadily forward without coming back to rework earlier stages of inlay. If you do that, you’ll spread the silver further and if it has nowhere else to go it will eventually be forced upward and out. When working the silver down and into position it’s a good idea to stop before you begin to touch the steel surface with the punch. If you do accidentally mark the ground you’ll find that it takes a lot of effort to remove the marks when finishing. You’ll also notice that I left the end of the wire untouched, this would be important if you were going to join the end to further inlay, you’d lay the last piece in place and work the two ends in together. As in a border or a circle for instance.



Step 5

Now the wire has been completely worked in and I’ve begun to chisel away the excess silver using the shishiai-bori chisel. You can also see the rough texture on the wire which the flat punch left. You could, of course, use a file to remove the unwanted material at this point but personally I find the chisel to be far more efficient and less likely to rip the wire out. Again, as with the punch work, try to stay just off the iron ground. This will again save lots of unwanted work later.



Step 6

Here you can see that all the excess silver has been chiselled away. You’ll know when you’re getting close to the surface of the steel when you begin to cut into the raised edges of the channel. It’s best to stop at that point. You’ll also notice a few marks at the right hand end of the inlay. Try not to do that!, it just makes for more work later, but even monkeys fall out of trees. Inlay like this can be further levelled by using scrapers, I haven’t used any here as their use is really the subject of another tutorial.



Step 7


The completed inlay. I’ve polished the surface level using only a Scotch stone, ( Water of Ayre ).

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It was worth the wait ...


the small details that you mention are exactly what i needed to know...


my goodness.. .. the sides of the inlay in your example are very straight...


just a few wee questions on the chisels.. to confirm what i think my eyes are seeing.. :)


the V chisel has sort of rounded convex sides ... and no heel ?


the textured flat punch used to set the wire from each side has abit of a crown on it ( slight convex )




thank you sooooo very much for this tutorial... !!


Greg :D:)

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Guest ford hallam

This is a further sequence of images showing the same procedure as shown previously. This time actually being applied. I'll keep the commentary brief as I think the images are, for the most part, self explanatory now. The brass and silver wire used is 0.2 mm thick, the gold wire is a little finer, 0.1. I think! :)




The design is first engraved using a “V” shaped chisel, then one of the edges is worked up vertically to form a raised edge.




One edge done, you can see the opposite edge of the groove is unmarked. These are the tools used so far.




Here, only one edge is complete, now for the other one.




This is brass wire being worked in. Notice the end hasn't been touched, that will be worked in when the wire is brought all the way round to finish the border.




That's the brass wire border in place.




This is the fine or pure silver being inlaid. I tend to gently lead the wire along the channel it is to go into.



Here you can see a line that will join another already inlaid, notice how this channel actually cuts into the existing line. This is to ensure that there is no break in the inlay. Elsewhere on this sample I've not done this and you can see the difference in the finished plate.



Hi Greg, keep watching...not done yet. This is why It's taken a while, so many images! :D



I am now going to add in some pure gold but as there is already quite a bit of inlay here I've removed the excess silver with a chisel. To make the silver wire that is already inlaid a bit more visible I've wiped it with a copper sulphate and salt solution. That's why the silver is pink now.






Working the gold in, it's so soft that initially I just push it in place with a hand held punch. Once it's all in place I secure it with a punch and hammer. That's a regular household pin I use as a scriber, it's held in a pin-vice, appropriately enough!






All the inlay is in place and I'm chiseling the excess metal off. It takes years of dedicated practice to get the brass and the steel on either side to peel off like a banana like that. :)




All the excess is now removed. I'd usually now go on to use a scraper to further refine the surface but as I've not done the tutorial describing their use yet, I proceeded directly to polishing level with a Scotch, or Water of Ayre stone




This is the plate after 20 minutes of polishing. It’s quite tricky getting it all to show up as it’s so bright.




Another view of the completed sample plate. The flower is just lightly engraved and may form the basis of another tutorial detailing yet another variation on wire inlay.

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Hi Ford,

that is fabulous, very clear.

I didn't realise until the last pic how small it was, could you perhaps put a 1cm sticky label dot in the shot to remind us of the scale. In all the instructions I have read in the past it always looks as if you are supposed to undercut , and I could never see how to do it, you have cleared it up completely,


regards Tim.

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This is a great tutorial, even (or should I say especially) for the uninitiated, such as myself...


Some basic questions I have are:


1. Are you pushing those chisels by hand, hammer tpas, or power tools?

2. How do you view the subject while working? Any magnification devices?

3. What kind of work do you typically use this technique in?


Forgive my newbiebess!

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Guest ford hallam

Hi Tim,


yes, the undercut thing is not always necessary, it may actually be a complete misconception of the process in some cases. I'll get a little 1cmm disc and include them as standard on all my images used for tutorials in future. I was wondering haw to maintain a sense of scale, it's a bit obvious really :) , thanks.


Hello Hovig,


glad it all appears clear to you, that was my motivation, to be as accurate as I could. I mean, I can't have everyone visiting my studio so this will have to do for now. :)

In answer to your questions; 1; I only use hammers, no noisy power tools for me. :) You need to be as close and direct as you can with this kind of work and I don't like to have any unnecessary appliances in between my fingers and the work.

2; I use a standard jewellers optivisor, and of late, reading glasses :D , oh the shame. :D

3; to be honest, I don't personally use this technique much, but it has been used in the decoration of arms and armour for centuries. It's a pretty frequent technique on tsuba.


cheers, Ford

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What a masterful lesson. You would make a great teacher! But then again that's exactly what you are doing. Teaching! Thank you Sensi I learned a great deal.


I would like to ask what may be a stupid question about your kagamibuta netsuke that you overlaid silver onto the iron disk. Why did you do all of that beautiful work that will be hidden by the lacquer bowl or is the netsuke designed to come apart? The reason I ask is that I have a number of kagamibuta netsuke mounted on tobacco pouches and the disk's are locked in place by a fitting and cord or chains. Also will the silver become loose when you carve and inlay various metals on the obverse side of the disk?


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Guest ford hallam

Thanks Gents,


I try to please :) . The trick with work that gets this fine, or small, is to use your sense of touch. If your initial engraved, or chiseled lines are accurate and true you have guide to rest the following steps in. You must maintain a consistent angle, rhythm, rate of tapping with the hammer etc. If you allow it, each step is guided by the preceding one. Does that make sense? I think that may be true of all of these types of technique. :)




The kagamibuta discs I make all come out easily. The one you're referring to has a wooden bowl but a copper rim to seat the iron disc. The scene on the back, (you haven't seen the silver mottling on the edge of the clouds yet :D ) is part of the "haiku" that the design on the front will hopefully evoke. I'm using the haiku concept in my conceptions more and more now, it works for me. :D The silver I've applied to the back won't be affected by what's happening on the front as the metal disc is 1.7mm thick. There is quite a lot of material scooped away to create a sense of perspective, also I used the disc the other way round from the usual convex face out. Mine is concave on the front to add depth.

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Hi Ford,


Great stuff!! I've seen quite a bit of this type of work on 18th century French and English firearms, and noticed that both techniques, regarding undercutting vs. not, have been used. I have also seen it hammered strait into a V groove, in which case is is usually partly, if not mostly missing. The English had a particular fondness for undercutting when applying inlay on their firearms barrels, using platinum or gold wire, and it is usually all there.


Great to see the process so clearly explained!


I have a couple of quick questions for you. The punch that you use appears to have a slightly textured face. Is this there to keep the silver from spreading while being tapped into place? Is the surface re-applied, as in your notes on foil overlay? And lastly, I've noticed that you prefer fine silver, over sterling. Is this because of it's extra softness?


Thanks, Phil

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Guest ford hallam

Thanks, Phil,


the punch is textured to help prevent slipping but I suppose it does in fact stop the metal underneath the punch from spreading too much. I'll note that in my descriptions in future. There are other processes which benefit from this little touch now that I think about it. cheers :D

I use fine silver both because its so soft but also because it generally doesnt discolour as much as sterling, particularly when working in copper alloys and patinating in the Japanese way.

There's no further application after the actual wire inlay, if I understand your question, although there is no reason why you couldn't do nunome over the wire. Interesting possibility, I don't think I've seen that before.



with regard to the variations of wire inlay, as I mentioned at the start there are at least 3 basic approaches, as you've pointed out and seen for yourself. :) In a similar way, although I was formally taught 2 of these by my teacher I occasionally saw other variations on antique pieces I restored. It takes a bit of basic understanding of the processes and some reverse engineering to figure out the methods. I've documented a few of these local variations, I'll detail some that might be useful in future tutorials.


Incidentally, if the wire is pulled out of the panel I've just done you'd see a undercut channel, the raised edges of the groove are pushed back and in when the wire is tapped in. So although I said I wasn't trying to cut an actual undercut when preparing the grooves, the setting of the wire creates this feature co-incidentally. Does that make sense?


Thanks for the great feedback everyone, this is really helping to refine the tutorials and the descriptions. There are so many details that can be so easily overlooked when it's only one person presenting material, but with a panel we get a multitude of views. I appreciate the considered questions and comments a lot. :)

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Will the photos on your website have an enlarge function? i can see what you are doing with the tutorial,but things still look small to me. have you though about showing line drawings of the chisel faces? i need to inlay .5mm brass wire into a project,but it is a little hard to figure out the width of the cutting tool and how deep to cut the lines for the inlay.

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Guest ford hallam

Hi Dan,


I hadn't thought about an enlarge function, I'll see what I can work out, there may be a better way... :)

I will have diagrams drawn up with the angles and measurements for chisels and hammers, so that should help clear things up. :D

The wire in the first sequence is about 1mm in diameter and the silver wire in the second sequence is 0.2mm thick. I'd suggest that the depth of your cut is about the same as the diameter you intend to inlay. The width of your initial line also should be no wider that the wire you want to inlay. The tools need to be delicate enough so that you can achieve that. I hope that helps.


cheers and good luck, Ford

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Truly fantastic tutorial here Ford! :D

Can't begin to thank you enough. I am in the process of creating my first true inlay on a ring I'm making right now. It is whitegold background with 18 kt yellow inlay. - The subject is a vining plant and will need to stay raised in relief in order to get some definition of leaves, etc. I just thought I 'd check out Jim's tutorial again before I started the cuts and here's your's as well. Between the two I think I will succeed. This forum is such an incredible happening - raising the level of workmanship and the ability to express and keeping these arts alive - how wonderful !!! :)



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