Friday, July 14, 2017

Project #8 - WA handle for 240 mm kurouchi Tanaka

Tanaka blue steel #2 knives are well known and belong to (price-wise) entry level 'proper' Japanese kitchen knives. One of the issues many users had with the damascus cladding was that it would oxidize rather fast and would take a long time to develop a stable patina. James from knives-and-stones brought an new version of the knife with kurouchi finish that should help to mitigate the reactivity issue.

I myself was intrigued by Tanaka knives for quite a while and once James offered the option to buy just a blade I had an excuse as I would make the handle myself.


I went with a 'standard' design with a wooden ferrule and wooden body of the handle with a dowel connecting the two and reinforcing the handle for more mechanical stability.


  • Ferrule: purple red heart wood
  • Handle body: black locust burl
I have not worked with either of the two woods before. However I really like the look of the red heart on the handle of my Carter and the locust burl has a very interesting figure and at the same time it is supposed to be very resistant to water damage.

The materials. The red heart looks a bit strange, but that is
because the block is covered with wax to seal it.

Making the handle block

I have started with cutting a piece of each material, cleaning and squaring it up on stone plate with sanding paper and getting it ready for gluing. I have used epoxy to glue the blocks together. I am growing fond of the G/flex epoxy as it has long pot time (not quite as relevant in this particular case), is rather liquid and most importantly holds very well.

Cleaned and squared-up blocks - ready for gluing

Letting the glue to cure for 24 hours
Once the glue has cured I have cleaned and squared up the block. I try to make sure that the bottom part of the blade is perpendicular to the sides, as it makes it easier to get proper alignment for drilling the hole for the dowel.

I also draw center lines on the block before I proceed with the drilling as that helps me to keep the track of where the center of the handle is. Before I start to drill I try to as sure as possible that the drill and the center of the handle are aligned as it is not easy to correct this afterward.

Cleaning and squaring up the block before the drilling.

Drilling the dowel hole. Do nut hurry this step.
Once the dowel opening was drilled I have proceeded to mark the handle for rough material removal. The aim is to get rectangular shape with close to final width and height.

Not shown here is a little 'tap' that I applied at the bottom in the center of the handle - that allows me to keep the track of the center of the handle even when the lines on the sides are ground away.

Marking the handle for further shaping

Detail of the marked handle.
It is important to mention, that while I do my best to mark the handle as precisely (and symmetrically) as possible - I will still check several times (in particular at the ferrule) that the dowel hole remains in the middle of the handle.

I use coarse #40 grit (fresh belt - cuts faster and heats up the handle less) belt to remove bulk of material and clean up on disc sander and subsequently by hand on sanding block.

Cleaning up of the coarse shaped handle.
Even though the handle does not have its final shape yet - I constantly check how it fits inside my hand. The best is to do this with a dowel and blade as the weight of the knife changes the impression how large or small the handle feels in hand.

Once the width and height of the handle was right I would then carefully chamfer the edges on the disc grinder to create the octagonal profile. This is a bit tricky as the grinder is very small (just 125 mm diameter). It needs to be done slowly and checked many times, so corrections can be made if necessary.

Note: While I have not tried it yet - this could as well be done on a sanding block with #120 paper.

Once I got the shape finished I would proceed with #240, 400 and 600 paper on sanding block + I would use a smaller block of wood of about 20 x 100 x 50 mm and would attach a double-sided Tesa tape to the long narrow sides and use it to attach sanding paper. That can replace the sanding block if you do not have one and also allows to round the edges on the both ends in a rather well controlled manner.

Final step is done with very fine steel wool - then it is onto oiling. I have used Tru-oil and applied 3 coats. After each coat would dry I would sand it carefully with the steel wool - just to get even semi-matt finish.

Tip: I recommend using some sort of gloves when sanding with steel wool, because the tiny steel particles with find every crack on your skin and your hands will turn black and will not be easy to wash.

Sanding the handle with seal wool

Handle nearly finished - see how my hands look like?


The dowel is made from beech wood. The main reason for this choice is availability of round stock (I use 12 mm for larger and 10 mm for smaller handles).

The length is based on the length of the tang + about 2 cm for the bottom part + about 5 - 10 mm that should remaining sticking out of the handle. That allows me to remove the dowel when doing dry runs (checking that the dowel, handle and tang all fit together).

After cutting it to length I cut a slot with a hack saw and then carefully clean and widen it with a belt sander and #120 belt until the tang fits sungly without pushing it aside. Then I carefully sand (thin) the dowel until it fits with not too much resistance inside the handle and allows to insert the tang. The fit does not need to be super tight at this stage as the glue will take some space and make the fit tighter.

I have installed the dowel only once the handle was final shaped here, but it actually makes more sense to install it after the dowel opening was drilled. That reduces the risk of damaging the handle during sanding.

Cutting the slot into the dowel. Try to stay in the middle.

Gluing the dowel. The metal piece is used to push
the dowel open to avoid the gaps around the dowel.

Once the dowel was glued the front of the handle was finished and the handle treated with Tru-Oil. I used 3 coats and sanded the handle lightly with steel wool after each step.

Finishing the handle with Tru-oil

Once the handle was finished I used G/flex epoxy to glue it onto the tang.

A bit unusual way to keep the blade in the upright position.

At this stage it would have been all finished, but After handling the knife a few times I realized that the handle is a bit on the thick side, so I went back to the disc grinder - carefully thinned the handle on all 8 facets and the re-finished it as above. I have removed about 1 mm in width and height of the handle. It sounds little, but it made a noticeable difference in how does the knife feels in hand.

Finished handle:

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