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Kitchen Utility In Desert Ironwood

Discussion in 'Fixed Blades' started by dancom, Oct 31, 2020.

  1. dancom

    dancom Dust Maker Best Shop Tool

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    Oh the underrated kitchen utility knife.

    In many kitchens, a nimble, medium-sized knife takes on most of the the day-to-day chores. This type of knife is smaller and lower profile than a chef's knife, but bigger than a paring knife. It will have a similar length handle to a chef's knife for a familiar work-feel. Ideally, the kitchen utility will be lightweight and the balance point will be dead-on the pinch-grip point slightly fore of the bolster.

    [​IMG]

    This blade is 6" long and asymmetrically ground, meaning the right side is beveled but the left side is relatively flat. Being asymmetric, the edge geometry pushes the thing being sliced away from the right handed user. It looks kind of weird having a bevel only on the right side of the blade, but it works very well.

    [​IMG]

    As desert ironwood is very dense wood, to get the balance right, I have used some dense materials like stainless steel and copper at the bolster. The hidden tang and a stainless steel screw extends secretly way back into into the handle. The back end of the handle is drilled with a Forstener bit to accept a special nut I made from some round stock. This allows the handle components to be tightened up. The nut hole is plugged with a tapered plug and epoxied. I chose a stabilized maple burl plug for contrast.

    [​IMG]

    I will put some construction details up after this.

    Happy Halloween!

    Thanks for looking,

    Dan
     
  2. Grayzer86

    Grayzer86 Active Member

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    Very nice piece Dan. I love the subtle texture that ironwood develops in its end grain.
     
  3. dancom

    dancom Dust Maker Best Shop Tool

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    Some details on the build...

    As I haven't contributed to the forum much lately, I wanted to show a walk-through of this hidden tang kitchen utility knife that I am just finishing up. You should be able to click on the images to see larger ones if you want.

    I started with a basic wooden pattern from the KN76 template. I cut the basic shape on the band saw from some S35VN 3/32" stock. This is quite a bit over thickness due to mill scale, typically 0.1" to 0.14" so it feels more like 1/8".

    [​IMG]
    Fortunately, I was able to get two blades out of a 2" piece of stock. So this will be the A model and a B model with follow.
    [​IMG]

    [​IMG]

    Once the rough shape is cut out, I go to the grinder and profile.

    [​IMG]
    I took some scale off with a 36 grit.
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    Drilled the tang screw hole. I cut the hole into a slot with the band saw. Do this before heat treatment or it will be a challenge later.
    [​IMG]
    I brush/dunk the blade in Condursal X1100 for oxidizing protection during heat treatment. This takes a while to dry, so I usually leave it over night.
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    In the oven at 860°C and ramp to 1060°C for about a 10 minute soak.
    [​IMG]
    Take her out and let it cool in the air. Wave it in front of a box fan or shoot some compressed air on both sides as it cools.
    [​IMG]
    The scale on the S35VN is more apparent than with other stainless steels and it's tough to grind off. A 36 grit ceramic belt is in order.
    [​IMG]
    Grinding in the basic shape. More emphasis is on the right side of the blade. I am looking for a sweeping line from the ricasso to the top of the blade.
    [​IMG]
    On the left side, it's a basic hand sand finish. I put some masking tape on the right side to protect the bevel from getting scratched up on the bench.
    [​IMG]
    Electro-etching the mark on the left side of the blade.
    [​IMG]
    Once the mark is washed with some Windex and fresh water I tape the blade almost up to the shoulder.
    [​IMG]
    With a file guide lined up I match the two sides. This will help with the bolster fitment.
    [​IMG]
    For the bolster I used a scrap piece of AEB-L. I use the Dremel to with a thin disc to cut a slot.
    [​IMG]
    Drilling into the slot makes for a pretty good line. These are really small holes. I normally start with 5/64", then slot with a 3/32", then break out the needle files. Yes, bits are occasionally broken in this process.
    [​IMG]
    If the tang is tapered correctly, the bolster will slide on and get snug when it's within a few thousandths. I use this oak "tang basher" clamp to hold the blade while tapping the bolster on.
    [​IMG]
    There's always some filing and fitting to get a nice tight fit. This is probably the most critical part of the build for visual appearance. Too much of a gap and it looks bad.
    [​IMG]
    The rest of the bolster pieces can have oversized slots. Precise gaps aren't really critical here. Just a fit that prevents the pieces from slopping around too much. As a rule, I put fibre spacer between all pieces.
    [​IMG]

    More...
     
    Last edited: Oct 31, 2020
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  4. dancom

    dancom Dust Maker Best Shop Tool

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    Continued...

    In the slot on the end of the tang I fit a stainless steel machine screw. This screw pulls all the pieces of the handle together during glue up. It will get shortened as needed later.
    [​IMG]

    In the block of ironwood I mark and bore out the cavity for the tang. I do this on the drill press and then broach the inside with an old jig saw blade.
    [​IMG]
    The block should slide on and be allowed to compress the bolster pieces.
    [​IMG]

    From the butt end, I drill a slightly oversized, say 3/16" diameter hole into the cavity. This will allow the tang screw (this one is 8-32) to slip through.

    [​IMG]
    With a 3/8" Forstner bit and oversize the hole, but only for about 5/8". The Forstner bit leaves a flat bottom hole, not tapered like a regular drill bit. This is important.
    [​IMG]
    From some 3/8" SS round, I drill and tap a section about 3/8" long. Then cut a slot on the band saw. The slot lets me tighten the nut with a screwdriver.
    [​IMG]
    I made a plug by taking a small block of stabilized wood and screw a wood screw into it. Then I cut the head off the wood screw leaving only the shoulder. I chuck this in the drill and spin it against a moving belt. As it rotates it makes a cylinder. Taper the cylinder very slightly and cut it off.

    [​IMG]
    With all the components dry fitted and lined up, I'll mix up a couple of tablespoons of epoxy.
    [​IMG]
    I like to use a popsicle stick and coat each surface while sliding everything together. Drip ample epoxy in the cavity. Excess will splooge out, but that's ok. Give the bolster-ricasso junction a wipe before setting it away to cure.
    [​IMG]
    The next day, I will start squaring off the handle with a 36 grit belt. Shaping it to what feels comfortable. I grind the bolster almost all the way to the ricasso. Usually I will leave about 1/64" on the top and bottom. Sometimes I take some of the masking tape off the around ricasso to gauge the bolster symmetry. It's really important here to imagine where the cavity is. The last thing you want to do is grind into the cavity exposing the epoxy inside. I like to use the plug in the butt end as a visual guide to prevent this from happening.
    [​IMG]
    After rough shaping, I'll follow the shape with 60 and 120 grit. Then I like to move to the slack belt with a J weight belt. I'll go 220 grit and 320, the 400. All following the same basic round and round motion. The edge of the bolster will be sharp. I knock this edge down with some 400 grit sheet paper and small backing block. Setting the angle around 45°.
    [​IMG]
    Over to the buffer for some light polishing on a clean cotton wheel. Ironwood is like magic here.
    [​IMG]
    Very little effort is required to make this amazing wood take on a shine. I normally don't use compound on the wood itself. I will however mask off the metal parts of the bolster with masking tape and use a little green compound to buff them to a shine.
    [​IMG]
    Once the tape is off the blade, clean up any excess epoxy. Acetone, laquer thinner work good here. I use an old artist's brush and a brass wedge to clean things up.
    [​IMG]

    If everything is done right, the joint of the ricasso and bolster should look clean. Again, I think this is a hallmark of a great looking knife.

    [​IMG]

    The last few things to do are set the edge and give the knife a cleaning with soapy warm water and a hand dry. She's ready to start using.

    Thanks for following along...

    Dan
     
  5. Dave Hodson

    Dave Hodson Member

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    Great looking knife Dan and thanks for the photos. It's nice to be able to follow along.

    Regards
    Dave
     
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  6. Joelsund

    Joelsund New Member

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    Beautiful knife Dan!
     
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  7. Grayzer86

    Grayzer86 Active Member

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    Dan, how long have you been using the Condursal and how do you like it? Have you done any plate quenching with it? I’m currently using foil, but it’s a pain in the ass making all the pouches, cutting them off, having them stick sometimes, warping AEB-L that is like mush before cryo while trying to get the foil off etc. This seems like it would be the cats ass especially for thin sections like fillet blades where I do all of my grinding post heat treat. I don’t know if it’s just me but I also seem to have times where the foil pouch appears to be what’s “causing” the warp.
     
  8. dancom

    dancom Dust Maker Best Shop Tool

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    Thanks guys!

    Brandon,
    I used to do the SS foil thing. It's a pain for sure. I have been using Condursal since Cal suggested it I think back in 2015. It works really well and has saved me piles on stainless foil. As far as cleanness, Condursal has never been as clean as tool wrap. Some alloys behave differently, vanadium seems to leave more scale. AEB-L leaves only a minimum of surface scale/Condursal residue that can be brushed off with a wire brush. CPM154 and 154CM are in the middle for post quench scale. Oil quench works ok too, but there will be some burnt oil to clean off. My thinking is meh, I am going to grind it off it anyways.

    I have pretty much given up on plate quenching AEB-L as I use 3/32" a lot. There might be a technique where you could drop the blade into the plates so the contact it even on each side. For AEB-L, I just hang air cooled steel and blow it with compressed air. Pretty cool to "hear" the steel hardening.

    @John Noon was offering ATP-641, which may be more accessible. Condursal is considered dangerous goods and shipping will be costly.

    P.S. In the above step-by-step, I mislabeled Condursal Z1100 as X1100. Fat fingers.

    Dan
     
    Last edited: Nov 1, 2020
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  9. Grayzer86

    Grayzer86 Active Member

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    I think my warping issue is being created by both the plates and the foil. I have tried many things to fight it and it’s a constant battle. I have wrapped the blade, clamped them all in a fixture to hold them dead flat and ran a 4 hour sub-critical anneal as suggested by Larrin. They come out of that stage dead straight. On the hardening cycle, they can sit in the kiln perfectly straight, and when I pull them out to get to the plates, they will curve like an inch or more in a matter of seconds. Heat is even and soak time is correct, and I can only imagine it’s something to do with the foil pouch causing the bend. Tried multiple sizes of pouches and even changing which direction I cut the pouch pieces off the roll, and doesn’t seem to make much difference. This happens with several steels I use for fillets and all are foil wrapped but doesn’t happen when I use 1/8 stock. Anyway, sorry to clutter up your post Dan.
     
  10. dancom

    dancom Dust Maker Best Shop Tool

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    I haven't had too many go snakey when pulling them out yellow hot. When plate quenching the tang will sometimes get a kick as I suspect the pliers are acting like a heat sink and cooling the tang faster than the rest of the blade.

    Sometimes I'd get a sweet straight blade out of quench that mysteriously gets a curve during the first tempering cycle. To remedy this, I clamp the blades to some 1-1/2" angle and before loading them in the tempering oven. Seems to be working so far.

    Dan
     
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  11. Griff

    Griff Active Member

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    Very cool Dan, beauty work as always, and really appreciate seeing your process :beer::beer:
     
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  12. John Noon

    John Noon Well-Known Member

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    I have begun offering ATP-641 since it is a water clay slurry there is no dangerous goods charge. Shipping Condursal by UPS was roughly $50
     

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