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Post: Ajikiri Restoration (Topic#847873)

ken123
Master Member KnifeNut!
ken123

Loc: Northern California
Reg: 04-16-06

03-23-09 18:03.39 - Post#1796458

This will probably be a fairly detailed series of postings for this thread. Hopefully I'll have the chance to demonstrate a number of techniques and would like your feedback on the decisions I made during the process.

In addition to knives, I also have an interest in fountain pens, which necessarily includes an interest in inks and paper as well as other writing instruments, including glass nibs.

One of the very top tier suppliers of products I have an interest in is sold by a company, Exaclair, which makes paper under several sub companies (Rhodia, Clairfontaine, etc), inks (J Herbin) as well as sealing wax (for leters) and other 'writing and paper related products. It is extremely extensive and I've only mentioned a few of their product lines.

I've reviewed a few of their products, and in the process, met a delightful individual who represents this company. In discussing their products, I mentioned to her that I also use paper to sharpen knives. She mentioned that she had a knife given to her by her Father that he had gotten in China and would like to know more about it. I posted pics a little while back to find out more information about the Kanji on the knife. It turns out that it is in fact a Japanese maker (thanks to all who helped). After seeing the pictures, I thought it was a wa-petty and asked if I could restore the knife. She was quite pleased and sent it to me. Given that the knife had a great sentimental value, I felt honored that she entrusted me to restore her knife. As much as possible I wanted to preserve it's sense of history, but bring out it's full potential as a knife.

Imagine my surprise when I received it. It wasn't a petty at all. It was quite thick and in fact was an ajikiri, a knife used to filet small fish.

Here's a couple of pictures of the knife as I received it. In the first picture, I've lifted up the brass ferrule to expose the wood with some blue crud that looks like copper sulfate, probably from the brass ferrule corroding.

http://www.kenss.com/pens/Quo/k1.jp...

Here's another picture of the back side of the knife, which you can see is badly and coarsely overground.

http://www.kenss.com/pens/Quo/k2.jp...

There's also some small microbevelled areas moreso near the front or tip area. (I'll talk more about this later).

The spine of the knife is coarsely ground and the spine is also smoothed on the front side. Both of these grinds look like coarse file grinds and the spine has a similar finish to the front. The tip is also dulled and rounded off (undermagnification, it looks like a chip rounded off).

http://www.kenss.com/pens/Quo/k3.jp...

Here's pics of the front of the knife:

http://www.kenss.com/pens/Quo/k13.j...

http://www.kenss.com/pens/Quo/k14.j...

http://www.kenss.com/pens/Quo/k15.j...

The handle has a few small 'dings', but is basically just in need of some cleaning. It looks like ho wood. The area under the tarnished and dented ferrule is in need of more cleaning and the ferrule extends past the handle so that it acts as a 'moat' with large dings along the edge and wood rot at the end of the handle.

The kurouchi finish is faded and has some corrosion spots on it as well. The inside arch below the machi is roughly finished as is commonly done with forged knives.

The front bevel has three grinds on it, one ending midway, with both angles ground using the same grit. You can make it out in the last image. Both are somewhat convex. The is also a mercifully very small microbevel as well. As will be seen more clearly later, the area near the heel of the knife where the single bevel meets the kurouchi is irregularly ground. It's also a bit difficult to discern, but you can see the line demarcating the hard core steel making the edge from the softer jigane or soft steel where the Kanji lettering is chiseled in by hand. There is no wear on the Kanji text with the chisel marks sharp and crisp.

There is evidence of pitting corrosion both in the front and back of the knife. Without getting too ahead of the story, I did leave some of this pitting and chose not to grind it out completely, but just leave it as a mark of it's age and history.

I'll post more pics later, but I wanted to get these initial pics out to get the discussion started.

---
Ken

Knife Sharpening Service

EP Stones:
http://www.jendeindustries.com/mm5/...

ken123
Master Member KnifeNut!
ken123

Loc: Northern California
Reg: 04-16-06

03-23-09 19:22.26 - Post#1796549
In response to ken123

Well, I wanted another opinion other than my own that I respected and since Curtis (C_Dawg) had just moved to the South San Francisco area and I was dropping my wife off at the airport, I though I'd have him look it over a bit. We pretty much had the same conclusions. We carefully looked over two ajirikis that Curtis had to see what areas had the kurouchi finish preserved and the spine was not kept as a kurouchi finish on these knives, so I knew it was appropriate to redo the spine.

Clearly the tip needed reshaping and this would involve grinding the spine, so the tip of the spine would have it's patina removed in the process. And since that would be done, I felt the rest of the spine may as well get the coarse grind or file marks removed. I didn't want to grind off the kurouchi finish but there was a coarsely ground bevel on the kurouchi side (front side) of the spine that I wanted to smooth out, so that it would be a more comfortable grip for a pinch grip style of use. The back side of the knife had the spine rounded a bit as well.

I also wanted to grind down the brass ferrule, so that, after hand polishing it and then gluing it in place, I wanted to grind it flush to the handle, cleaning out the crud in the process, but not scrape the knife in the process.

Before doing this the handle needed cleaning, both above and below the ferrule. I polished the ferrule with 400 grit wet dry sandpaper, then sanded the handle with 125 grit sandpaper. To clean under the ferrule, I pushed it forward all the way and cut 125 grit strips and 'shoe shine' polished the wood down to good wood, loosing surprisingly little wood. After polishing the handle with 125 grit, I followed this by 400 grit paper and then finished it with a mineral oil beeswax mixture, the same stuff I use for cutting boards. This would protect the handle from the stone grits dirtying the handle during the sharpening process.

The next step was the coarse work with the belt sander. The top of the brass ferrule was ground flush to the top of the wood handle under magnification (surgical loupes at 2.5 x), being careful not to nick the knife tang with the belt, using both the area under the belt support and the slack portion of the belt. There was still some small dings left, but I felt that removing them would probably do more damage than good and probably ruin both the handle and ferrule.

Next I started out with the belt sander and reshaped the tip rounding the spine until the point was reestablished. Then I used the slack part of the belt to remove the coarse grind marks. This gave a convex shaped spine, Then very carefully, under magnification, I ground the file marks next to the kurouchi finish, carefully avoiding the kurouchi finish.

---
Ken

Knife Sharpening Service

EP Stones:
http://www.jendeindustries.com/mm5/...

ken123
Master Member KnifeNut!
ken123

Loc: Northern California
Reg: 04-16-06

03-23-09 19:45.53 - Post#1796568
In response to ken123

Cleaning out under the ferrule before gluing:

http://www.kenss.com/pens/Quo/k16.j...

The spine and tip after smoothing and reshaping as well as after the ferrule has been ground down. Sorry, the only pic was out of focus at this stage.

http://www.kenss.com/pens/Quo/k17.j...

Here's the handle cleaned up before applying the mineral oil beeswax mixture.

http://www.kenss.com/pens/Quo/k19.j...

---
Ken

Knife Sharpening Service

EP Stones:
http://www.jendeindustries.com/mm5/...

aaqjr
Master Member KnifeNut!

Loc: Los Angeles
Reg: 10-08-06

03-23-09 20:27.36 - Post#1796611
In response to ken123

Wow! Can't wait to see the rest!

ken123
Master Member KnifeNut!
ken123

Loc: Northern California
Reg: 04-16-06

03-23-09 20:50.16 - Post#1796632
In response to ken123

Now for the back of the knife. As most of you know, the back of a single bevel knife is hollow or concave and you don't want to grind this out or use up this metal frivously. Well in the convex hollow the metal had some bad corrosion and some moderate pitting. I addressed this first.

I use the grit from waterstones and apply it to paper. Two of my favorite stones for this are the Naniwa 150 Grit Ohmura and the 2k grit stone in the same series.

For the paper I use some Rhodia paper, made by one of Quo Vadis' companies. Specifically I used a sheet of A$ 210 x 297 mm or 8.3 x 12.7". It's 21 lb paper (80 gm / square meter) in weight with 5mm grids printed on it. One of it's properties is that it is exquisitely smooth, a property appreciated when writing with fine tipped fountain pens.

Another property that I appreciated when making 'sandpaper' using the Ohmura was this paper's abrasion resistance. When I use postit notes or copy paper, one stroke of stone 'mud' is all you can do before the paper tears apart. This paper will take more abrasion, allowing a thicker and more uniform coat to be applied. Nice! It also held up well when using it as sandpaper.

I used this paper to clean out the hollow convex area of the back of the knife. I followed this with 2k grit paper, made in a similar manner. In both instances, you cut a little inch or 1.5 inch square and use your fingertip to follow the curve of the hollow. This produces minimal abrasion loss, in fact making the hollow ever so slightly deeper, a good thing. There was some deeper pitting that I didn't remove, again leaving a sense of oldness and history to the knife.

Here's what the knife looked like at this point:

http://www.kenss.com/pens/Quo/k21.j...

Here's some Rhodia paper impregnated with 150 Ohmura grit. This gives a fine finish than 150 grit, which seems to be true for all the stone grits I've tried.

http://www.kenss.com/pens/Quo/k22.j...

Here's what one of their pads looks like so if you see some in the store, you know what to do

The orange pad below it is an even larger size (A3), which I use for writing out large tables of data.

http://www.kenss.com/pens/Quo/k23.j...

http://www.kenss.com/pens/Quo/k24.j...

---
Ken

Knife Sharpening Service

EP Stones:
http://www.jendeindustries.com/mm5/...

ken123
Master Member KnifeNut!
ken123

Loc: Northern California
Reg: 04-16-06

03-23-09 21:01.29 - Post#1796642
In response to ken123

Thanks for posting, Arturo! Lots more to post! Feel free to ask questions as I get these posts in, since it's lots more fun to discuss at each stage of this restoration. I'll be talking about paper a bit, since this is somewhat unexplored technology for knife sharpening and conversely, pen afficianados don't think about their fine papers as being used for primo knife sharpening paper.

The idea of using grit on paper is really a derrivation of what sword polishers do with their chips of stone, gluing it to paper to polish their swords, following the irregular curvature of the blade profile. I'm finding this an improvement from this ancient tradition dating back hundreds if not even more years. I find that the properties of the stones are actually enhanced, yet still present, quite an improvement over commercial sandpaper.

---
Ken

Knife Sharpening Service

EP Stones:
http://www.jendeindustries.com/mm5/...

ken123
Master Member KnifeNut!
ken123

Loc: Northern California
Reg: 04-16-06

03-23-09 21:56.06 - Post#1796667
In response to ken123

Well, the back isn't finished, but I wanted to go to the front bevel next, returning to the back afterwards. I do this because I don't wish to unnecessarily grind of extra steel from the back.

Here I switched from hand sharpening techniques to using 'The Gizmo'. Why? Because there was no single established bevel and it was not a flat bevel. So rather than following the existing bevel I wanted to DEFINE a new bevel precisely. I also wanted to measure the bevel angle. So, I used the magic marker (Sharpie) trick, painting the single bevel surface up to the kurouchi. I used a DMT coarse plate and tested the bevel, finding that it touched first at the point midway where the two grinds on the single bevel met. If anyone wants it, I'll draw this out to clarify it. I finally settled in to deciding to go with a 20º bevel angle, which cleanly reached up and slightly straightened out the edge of the kurouchi line and met the edge of the knife as well. I hit this to within a few tenths of a degree

At this degree of precision, I noticed an interesting effect - the tip area and the heel didn't become a part of the plane. They looked low, but after more grinding, it turned out that the 'problem spots' were the two far ends of the kurouchi border, which had not been completely ground out and were sticking up. By concentrating on these ares, I eventually got the entire surface ground out, but for a very small area in the heel. This level of precision, combined with the flexibility to specifically control the grind at specific points along the knife gives an unprecedented level of precision. I did this until I got a slight amount of burr along the edge.

Why not a complete burr. Because the back was not yet flattened so I didn't expect burr to form yet until refining the back side.

I flattened the back side using a DMT coarse plate. I know, this is very agressive, but the back needed major work to remove the coarse grind marks and approach a flat edge along the length of the blade. I removed enough metal to get it flat to the edge for the entire length but for a small area near the tip which had a backbevel that to completely remove it would take off just too much metal.

I followed this with ohmura paper, followed by 2k Naniwa paper as described above, but this time the paper was tacked to a piece of glass backing, giving a dead flat surface.

Here's what the back looks like at this stage. As you can see, a good bit of the hollow area has been lost, but it's getting good now.

http://www.kenss.com/pens/Quo/k25.j...

Here's the knife clamped to the Gizmo with a DMT coarse plate in the stoneholder. If you look carefully you can see where the first couple of scratches have been made midway along the single bevel (blade road).

http://www.kenss.com/pens/Quo/k26.j...

After I established a flat bevel with the Gizmo and the DMT coarse, I switched to hand sharpening techniques for the remainder of this work. Once the angle was established acurately hand sharpening seemed appropriate, since I wanted to use my Chocera stones, including my 1k stone with a base on it

More fun ahead ...

---
Ken

Knife Sharpening Service

EP Stones:
http://www.jendeindustries.com/mm5/...

ken123
Master Member KnifeNut!
ken123

Loc: Northern California
Reg: 04-16-06

03-23-09 22:10.55 - Post#1796674
In response to ken123

Here's an interim picture after initial flattening of the front bevel:

http://www.kenss.com/pens/Quo/k27.j...

---
Ken

Knife Sharpening Service

EP Stones:
http://www.jendeindustries.com/mm5/...

ken123
Master Member KnifeNut!
ken123

Loc: Northern California
Reg: 04-16-06

03-23-09 22:47.52 - Post#1796688
In response to ken123

OK Time to go to the choceras, but first some work with the Ohmura 150, since it wasn't quite flat at the two ends yet. I followed this with the 400 Chocera and then the 1000 Chocera, back and forth to the 400 until it was 'right', then on to the 2000 Chocera, 5000 and finally the 10000 Chocera.

I chose this series over my GlassStones because it is more 'forgiving' of variances in flatness, specifically the bevel in the back and front at the tip and heel. Pretty amazing stones and a pleasure to use. I've reviewed these stones elsewhere - what can I say? Priocey but nice. I used each stone a fair bit rather than just a touch as I would on double bevelled knives. I didn't take a bunch of pictures at each level or microscope pics, but the knife became quite sharp

I generated burr at 400 grit and made no cosscious effort to remove burr other than alternating sides at the first hint of burr, going all the way to 5k. At this level the first part of the edge near the tip wasn't as sharp as the mid point and heel. The reason? - the overground back bevel near the tip. A couople of strokes at 5k following this overground and - immediate sharpness! So at this point the front AND back have been brought up to a 10k Chocera grit finish and the overground back bevel has also been freehand polished to a 10k Chocera level finish.

After the 10k edge, I used Boron carbide (1 micron, Hand America preparation).

I used this boron carbide on another Rhodia pad, a number 13 pad, 4.1 x 5.8 inches also 5mm grid. I used two glass plates, one to support the paper and another to spread the Boron Carbide (BC). The paper is microperforated, so it is easy to tear out this paper from the pad without tearing the paper or leaving a rough edge. I also polished the spine with 10 chocera on paper and touched up the front and rear bevels with 10k Chocera paper. Yes it gave an even finer surface

I spread the BC by placing a few drops on the paper and smeared it with the glass, eventually getting a fairly even (and heavy) coating. I use this to polish the back surface and front bevel and polish the back microbevel near the tip and put a single stroke of microbevel on the front edge. Ever see a ajikiri push cut 2 inches out

I labelled the paper with a waterproof ink, J Herbin's Lawyer's Ink or Authentique, an ink which has been used and preserved for 300 years, not an ideal ink for fountain pens, but superb for dip pens or glass pens.

I also used J Herbin sealing wax to 'stick' or affix the Rhodia paper with the BC grit on it to the glass. You melt the tip of the wax stick and let it drip on the edge of the paper. Sticks great to glass.

As a final stropping, I used the Rhodia paper stuck to the glass with nothing on it. So smooth and so flat that I could strop with both edge leading and trailing strokes without cutting the paper (no pressure).

I made it through the entire sharpening process without cutting myself and wrapped it with two layers of bubble wrap and closed it with some painter's tape. I GENTLY pressed down the end of the tape to the bubble wrap and the knife went through the bubble wrap and 'nipped me'. Oddly, it made me smile

Some final pics to follow...

---
Ken

Knife Sharpening Service

EP Stones:
http://www.jendeindustries.com/mm5/...

ken123
Master Member KnifeNut!
ken123

Loc: Northern California
Reg: 04-16-06

03-23-09 23:15.44 - Post#1796702
In response to ken123

Here's pictures of the Rhodia small notepad with a sheet removed

http://www.kenss.com/pens/Quo/k28.j...

Then set on the glass plate with the liquid suspension of Boron Carbide.

http://www.kenss.com/pens/Quo/k29.j...

Here a few drops of BC are dripped on the paper and QUICKLY smeared along the paper. This is repeated until a heavy coating of BC has been applied to the entire surface (with a bit of room left on the top to label the page.

http://www.kenss.com/pens/Quo/k30.j...