Project #24 Refinishing and rehandling of 210 mm Yoshikazu Ikeda gyuto

This was supposed to be a purely rehandle job for a friend of mine who got his gyuto from Bernal Cutlery. But I took long to find the time to do this job and I have underestimated the humidity and temperature conditions in my shop and the lovely, brand new knife rusted pretty badly under my watch (stored in its own box).

This meant, that before any rehandling could take place, a complete re-finish of the whole surface of the blade was necessary. Oh well.

The original finish was a rather common with a rather nicely polished hagane and with a jigane having a 'sand blasted' look.

This photo shows the still more-less original condition of the blade

I have to admit that when I unpacked the knife I was stunned - the rust was everywhere and from the first sight it was obvious that it was not just on the surface. This is not how you want to present a 300€+ knife made by one of the most prominent Japanese smiths to your friend.

Condition of the blade :(

Condition of the blade :(

Look at that kanji - I was nearly crying.

Well - it took me a few deep breaths, then I have sent a message to my friend with these disturbing images. I am sure he must have been biting his tongue as he replied to me way too kindly. Obviously I was going to get the blade full refinish and only then make a new handle for the knife.

Blade refinishing

Before taking out the big guns I first decided to clean the knife and see how the blade looks underneath the rust I have used BKF (Bar Keeper's Friend) to clean the rust off.

About to start with the cleaning

The result was as expected - the rust pitted (micro-pitted) the blade and the blade had to be hand sanded until all the rust was gone and the sanded up to high grit.

Micro-pitting on the blade.

This meant that I had to turn to hand sanding. After several attempts I went all the way down to #400 grit (well, it could have been worse)

Since I was going to refinish the whole blade, I took the chance and rounded and polished both spine and the choil of the blade. I used sandpaper in different grits rolled on a 12 mm in diameter piece of beech that I use for dowels to work on the choil.

This is how the choil looked before refinishing.

Choil rounded and polished.

Spine lightly rounded and polished.

As usually when hand sanding a blade - I would use an orange Tesa tape to protect the downwards facing side from being scratched while I was working on the upper one.

Applying the Tesa tape to one side at a time.

Here I found another way to make a mistake. This blade has (as most well done Japanese gyutos do) a rather complex geometry - best describable as 'blended wide bevel'. In other words the grind from the edge was nearly flat (though not 100%) up to about 15 - 20 mm from the edge, then a shoulder could be observer and the blade would be then again more-less flat up to the spine. Since these wide bevel and the bevel reaching to the spine were blended, there was no apparent shinogi line.

When I first started with the hand sanding I first used a wooden support to which I glued a small piece of a PC mouse-pad to get a soft backing. The reason to do this was to attempt to give as little change to the geometry as possible.

Only for illustration of the sanding bar - you can see to soft
backing made from the mouse pad. The bar is 20 mm wide
and 10 mm thick (not the most comfortable indeed)

- but - 

Using soft support when grinding close to the cutting edge meant that if I would spend a little more time on one spot removing rust pitting, then the soft baking would 'embrace' the cutting edge and would grind directly the cutting edge, not only the bevel. Of course I realised thin only after I cause a small 'dip' in the cutting edge. There was just one way to fix that - grind the cutting edge until the dip was removed and then adjust the thickness behind the blade. This was all pretty minor, but cost another hour of work.

After this lesson I have used a piece of steel stock with rounded edges as a sanding bar and only used the wooden bar with the soft backing when smoothing things out at the end of each grit of sandpaper before I would move to a higher grit.

I went through 400, 600, 1000 and 2000 which gave me a semi-mirror finish. At this point I agreed with my friend that I will not do any more refinement. 2000 grit finish is indeed not a proper kasumi finish - that would require to finish the blade on stones and then with fingerstones, but that would be several hours more of work (and this project was at this stage already heavily delayed).

My typical hand sanding setup. Here the geometry of the blade is
partially visible.

after bottom wide bevel was sanded with higher grit you can see the
transition in the blade geometry.

Semi mirror finish of the blade after #2000 sandpaper

The whole blade refinishing took me about 6-7 hours, most of that was hand sanding. Lesson learned.

The last adjustment I did on the blade was to shorten the tang by about 15 mm. This is not something I would normally do, but the blade really had a large tang and since I knew that the handles will be relatively heavy (turned out to be a bit more than 60g each - about a double of the weight of the original handle), than shaving off a few gram was going to help to keep the center of mass in front of the heel.

Handle making

My friend could not decide on the handle material, so I have offered to make two so that he could pick one.

Both handle were going to have the same design:

• black buffalo horn ferrule
• ivory micarta spacer
• stabilized handle block (from outbacktimbers, great stuff)
• beech dowel to connect the handle components

Handle materials

 The handle making was pretty straight forward:

• square the horn roll ferrules and handle blocks up & draw centerlines
• drill the spacers, the horns and the blocks with 12 mm drill bit
• make sure that all the parts align with
• glue the handles using a special vice

First handle being glued. The dowel would
be removed once the the vice was tightened

Normally I would first glue the prepared and pre-fitted (to a given knife) dowel inside the handle block before I would glue the spacer(s) and ferrule, but here I did not know which of the handles will be picked when finished, so I glued the handle without the dowel. However I had to make sure that all 3 components align on the same axis. For that I have adjusted a small jig - gluing vice such that it would allow me to insert and remove a longer version of the dowel. I would keep it inserted while the handle was being glued and placed in the vice and I would only remove it once the vice was tightened . This way I could make sure that the handle components were on axis and also that there would be no leaked glue inside the dowel opening. 

Once the glue cured I used my (recently acquired) small band saw (Record Power BS250) to cut the blocks close to the final size of the handle - this would save me a lot of time doing the same with coarse belts.

Note: If you get a small band saw like I did (350W, 10") than it is crucial that you get the best blade for it you can find. This will make a HUGE difference on the cutting performance. I got a 1/2" wide blade from TuffSaws after I discussed with them what I want to use the blade for. I was not able to cut a thin pieces from hard wood that was 3-4 cm thick. With the new blade that was no problem. The keyword is to go SLOW.

Cutting down the glued handle block to shape.

After cutting I would clean up the block on #80 sandpaper on a sanding block and bring it to the final size before sanding the octagonal shape.

Handle block ready for octagon-shaping

As usually the shaping was done with the small 125 mm disc sander that is part of the belt grinder with #150 grit disc.

Handle shaped to octagonal cross section.

In subsequent steps I have sanded the handles with #180, #320, #600 and #1000 sandpaper and chamfered the edges. The final polish was made with steel wool #0000.

Even though these handles were made from stabilized wood I still have them 3 very thin coats with TruOil (applying and immediately wiping away & polishing with a paper towel and allowing to cure).

Finished handles.

Here tog 2 other handles.

Once the handles was finished it was time to check how they fit the blade (at this stage still not refinished):

Handle No.1

Handle No.2

Finally my friend picked the handle No.1 Once that decision was taken I made a fitting dowel for the tang and glued it inside the handle.

The next step was to glue handle on the knife. This was done in 2 steps. In the first step the blade the actual gluing would take place. Here I would only concentrate on making sure that the dowel slot was full with glue (once the tang was inserted) and that no glue would be left either on the blade, or on the handle. The the glue would be allowed to cure. 

To make it easier for the epoxy (G/flex) to flow inside the rather narrow opening I heated it up with a hot air gun and I then also heated up the tang of the knife before inserting it inside the handle. This makes the process much easier. The heating up may somewhat speed up the curing process, but since G/flex has 45 minutes pot time, this was not an issue.

Handle adjusted to fit the tang with as nicely
as possible.

In the second step (once the epoxy cured over time) I would mix epoxy with somewhat shorter pot time (15 minutes), heat it up and apply just enough of it to fill-in the voids between the blade and the handle that were left as the epoxy cooled and contracted a little. I again used hot air gun to make sure the glue will fill the narrow void and that bubbles would be allowed to escape.

Add caption

Filling the gap with additional epoxy in the second step.

I would then wait until the glue would start to show first steps of curing and only then I would wipe the excess with small pieces of paper towel that I would roll around an ice stick and dip in Toluene. If I would do this sooner, I might 'pull' too much glue out of the voids I was trying to fill.

The finished knife (photos courtesy of my friend)

Lessons learned:

• Store carbon steel blades properly - dry, oiled and wrapped in a VCI paper.
• Think of side effects when hand sanding a blade - there is time when to use hard and when to use soft backing to the sandpaper.
• Get the best blades possible for your band saw, they work wonders.
• Hot air gun will make it much easier to get epoxy inside tight places (I use it now with every handle installation)