Project #25 - 150 mm tall petty from 1.2442

This was one of the fastest projects I have finished till today. A friend of mine who got a Moritaka AS 150 mm petty just a few months ago managed to bend it at work (while cutting !) and was in a need of a stronger & stiffer petty.

Since we have some experiments with 1.2442 steel in mind for the near future, I offered him that I could make him a petty from this steel as I have not used it yet (though I bought it about a year ago).

From the design point of view the idea was simple - ca 35 mm tall, 150 mm on edge, WA handle.

The blade

As usually, I have started with the blade design. Here I have decided to use the profile (of the cutting edge only) of a Yoshikane SLD 150 petty, which has proven to be very practical. I have then adjusted the height as the Yoshi is only about 30 mm tall. 

This was the first time I have worked with the 1.2442 steel (not in production since quite a while), which bears some similarities (composition wise) with Japanese blue #1 steel. When cutting the steel with a hack saw one would notice that there are alloying elements present, but it was still easier to work with than for example Niolox, though not as easy as O1.

All of the pre-HT steps were 'standard' ones, so here just shortly:

• cut out the blank from 2.7 mm thick stock with a hack saw (yes, I leave the tip flat until after HT)
• finish the profile with a #40 belt
• clean up to #220 belt
• paint the edges blue with a permanent marker
• scribe the center line on both edge and spine (including tang)
• grind the bevels and distal taper - I went down to about 1 mm on edge to minimize the risk of warping during the HT - I have not worked with this steel before.
• Finish the profile of the heel (much harder to do after HT)
• Sent the blade off to HT to Achim Wirtz to be hardened to HRC63

Blade after HT.

After HT I would first thin the the grind down to last 10% (leaving about 0.3 mm edge thickness) with the #40 belt.

Grinding after HT with #40 belt

Distal taper - the tang will be worked on a little later.

Close to final geometry

At this stage I would go briefly to 300 water stone from JNS to check and clean up the bevel grind to make sure that there are no defects like over-grinds and low spots. I was not trying to get the final bevel grind - really just checking the consistency. It all looked pretty good, just at usually the heel was a little thinner last 2-3 millimetres.  I was not trying to get 'perfect' bevels at this stage or even shinogi line.

After that I would proceed with shaping the tip and tang of the blade.

Shaping the profile of the tip (after working the bevel on 300 stone)

Once all the coarse grinding was done (blade geometry, tip shape, tang shape) the next step was scratch removal. During this step I would not worry too much about that bevel I did on stones as I was not trying to get as little as possible material removed. I would proceed with #60 and #120 ceramic belts and then proceeded to 3M Trizact 'gator' A100 belt. The A100 would be around #200 grit and frankly I would have been preferable to have the coarser A160, but it appears not available in 1x30" size. 

Grinding with #60 belt under different angle to remove all #40 scratches.

After the A100 I went  to A65 - always slightly changing directions. At this point I realized, that I forgot to round the choil and spine (ideal point to do that would have been after #120 belt), so I first coarsely rounded the spine with a belt and finished to #1000 grit by hand. The choil was rounded entirely by hand and then also polished to #1000. Once these parts were done I continued with #65 and #45 Trizact belts.

Rounding the choil with #240 grit. The light accentuated the scratches,
they were far less scary :)

At this stage of finish I would normally switch to hand sanding going to whatever grit would look nice (I am normally by semi-matte finish). But I was under a time pressure as I wanted to present the knife to my friend (who did not expect to see it anytime soon). So I took a shortcut. I decided to make  an experimental finish. I had a second session on the stones - this time a progression of 300, 1000 and 4000 and ground the bevel down to is final edge thickness (not more than 0.1 mm before sharpening).

I followed by finishing the blade with A30 belt making sure all scratches are gone. I tried to avoid the bevel as I did not intend to remove any larger amount of material there, just final finishing before sharpening once the knife was completed.

In the process of last scratch removal with A30 belt.

The last step on the belt grinder was made with a fine (blue) Scotchbrite belt. There I just wanted to get the finish a little smoother (the belt is nearly too sharp for that). I knowingly also toughed the the bevels so that I had an even finish on the 'shinogi' line.

Finish after fine Scotchbrite belt. Again - the direct light makes the scratches
to stand out more than they would appear under softer light.

The same Scotchbrite belt finish under different angle

The blade would not be finished without a logo ;) On this blade I only did deep etching with DC without using AC afterward to blacken the logo - as was wished by my friend. I have to admit I like this less obtrusive and will probably stick to it with most of my future knives.

About to etch the logo.

As always until now I have used the Electrolyte 94 as electrolyte, 12V setting on the etcher and etched for 6x3 seconds (e.i. lifting the etching head every 3 seconds so that the gas that is produced in the process can escape and does not cause uneven etching

The handle

While waiting for the blade to come back from the HT, I would start to work on the handle. The design was again a 'standard' one using buffalo horn for the ferrule and stabilized & dyed Australian wood (curly spalted Boxelder) with a beech dowel inside. Since this handle was a rather subtle one, I decided that apart from cutting the ferrule and handle block to rough shape with a band saw, I will do all the shaping & sanding by hand on a stone sanding block.

Handle materials

The basic process of the handle making:

• cut the & square up a piece of buffalo horn and handle block
• drill the ferrule and handle block
• check that the handle block axis (defined by the drilled hole)aligns with the ferrule & glue them (using my own gluing press that allows using a piece of dowel material for initial alignment)
• Once the glue cured clean & square up the future handle

Handle components cuts and squared-up

Gluing the handle using a jig. The dowel is
removed once the handle is clamped down.

Normally I would glue in the devel before I would glue the handle parts together, but this time it took longer to get the blade back from the HT and I did not want to loose too much time, so I glued-in the dowel at a later stage (when the blade was back and I could test the fit).

Handle squared-up after gluing and ready for shaping

Normally I do the rough shaping (= final height and width including distal taper) with a coarse belt, but I decided to do this completely by hand. I would do this on a #80 grind sandpaper taped flat on a stone (old table-top)

Handle after coarse shaping

Once the desired height and width (with about 1 mm in every direction left for further sanding) was achieved, I continued through 180, 320 and 600 grits.

Coarse shaped handle refined to about #600 grit.

In the next step I have sanded the handle to octagonal shape. Again - this is something I usually do with the little disc sander that is part of my belt sander, but I simply wanted to do it by hand. This is an interesting experience and allows to get the feel of how important is even pressure distribution.

Once the handle was shaped and finished to #600 grit the blade finally arrived from the HT and so I could make the fitting dowel for it.

Handle shaped and finished up to about #600

I have to admit that since I got the little Record Power BS250 band saw, the cutting of dowels got so much easier. Once the slit was cut it gets widened on a belt sander (#80 or #120 belt seems to work the best) until I get a nice, easy with with the tang and the handle

Dowel cut, now the slit will be widened with a belt sander.

As you may see in the photo below - I tend to make the dowel some 5 mm longer that the drilled opening in the handle - the reason is, that the front side of the dowel might have suffered uneven grinding with the belt sander, or it might get sanded by a rasp after gluing. So I rather make it a little longer and then sand to length after gluing.

Checking the fir.

Once the dowel fits nicely I glue it inside the handle with epoxy. I tend to create small 'pockets' (dips) on the side of the dowel with a round file so that if there is a bit too much epoxy it can go there instead inside the slit itself. You really only want to use just a little epoxy at this stage, because if too much of it leaks inside the handle you will spend a lot of time with needle files and rasps trying to get it out.

As always I use a piece of scrap steel shaped like a very thin edge to push the dowel open while the glue cures, so there will be no gaps between the dowel and the ferrule.

Gluing the dowel

Once the handle was finished this far I tested a little more to see how it feels in hand (with the blade inserted) and got the impression that while I like the overall size and shape, it would feel more nimble if it were a little narrower in the front. I have have covered most of the handle with tape (remember, it was already sanded to #600) and used #180 sandpaper to give a bit of horizontal distal taper to the ferrule.

About to start sanding the distal taper.

Thanks to the fact that the handle already had a #600 finish, it was very easy to observe where the material was being removed. I started by tilting the end of the handle upwards very slightly and applying pressure only on the very front of the handle. I would stop after every few passes and check the progress. Once I have established a new bevel I would continue until it reached the end of the ferrule. I would constantly check and if necessary compensate any unwanted tilts.

After first few passes - looking good so far.

The horizontal distal taper sanded in.

Once the taper was sanded the whole handle was finished up to #1000 grit and the front and rear edges were chamfered. I also used steel wool when finishing the handle, but it was not a particularly good idea with this wood which has a somewhat coarse and not homogeneous structure and the steel wool would tear little pieces out. 

Front side of the handle sanded to #1000 and the opening lightly filed
so that the shoulders of the blade would fit nicely.

Because of the slight tear-out I have the handle once coat of Birchwood Sealer & Filler, sanded it lightly afterward and followed with 2 or 3 coats of Tru-Oil for a good measure. As always, I would apply the Tru-Oil and while & polish the handle with a paper towel immediately after the application.

Tru-Oil curing after application.

At this stage both the handle and the blade were finished (the blade will still get slight refinishing of the bevels on stones) and thus ready for gluing.

Well, let's do the last step.

As with the last few handles I would heat up the G/flex epoxy to make it easier to get it inside the narrow tang slot, then heat up the tang of the blade and insert it carefully. Once the epoxy started to come out I wold let the blade to sink in the handle slowly while wiping the excess epoxy. Since I use G/flex which has 45 minutes pot time I did not have to hurry and even had time to take some photos :) Once the blade was in place I would heat the top of handle gently with the hot air gun to allow most of the bubbles to escape.

I have used small pieces of paper towel wound round ice stick and dipped in Toluene to clean up the blade and ferrule from epoxy rests.

The handle is in place, the last bit of epoxy is still to be cleaned off.

Gluing the handle this way also means, than more often then not the epoxy will shrink a little while cooling down (some air bubbles always remain trapped inside) and thus a shallow void between the dowel and the blade would appear. This is is filled with epoxy (Blade Bond Ultra that has pot time 15 minutes) the next day in a similar manner - the mixed epoxy is heated up and just very little of it is applied to the contact area between the blade and the dowel. Heating the applied epoxy with the hot air gut would allow it to fill the narrow void and the bubbles to escape. This time however I would wait until the glue starts to set it (get thicker) and only then I would use clean the rests off (paper towel, ice stick and Toluene). If I were to do it too soon, I would risk 'sucking' out the epoxy from the freshly filled void. The reason to use different epoxy is that I do not want to wait for an hour for the epoxy to start to set it :)

Gap filled with the epoxy, the excess was already removed.

After last clean-up of the bevels on the stones the knife was officially finished.

Finished knife

Lessons learned

Not so much went (thankfully) wrong this time

• 1.2442 steel was nice to work with (in comparison to Niolox every steel feels nice to work with though) 
• The "narrow wide bevel" grind appears to work very well (feedback from my friend)
• The gentle horizontal distal taper improved the feel in hand considerably
• I am very happy how the belt finish turned out, but I have a lot of room for improvement (the finish and the efficiency) there. I will need to experiment with different belts to get the most out of it. I plan to make this simpler but very functional finish in the future more often (not only on Niolox)
• I may be doing more knives like this one in the future. In general I will probably start to make small batches of knives once I get a knife that I (and in particular my test users) like.
• Again - I was in a hurry to finish this knife and so I did not make proper photos or a video. I need to improve on that.

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)