It’s useful on occasion to revisit one’s earlier work. The two photos above contrast the results of my ‘smithing over a six year period. The first picture is my latest hori hori creation, forged from an old railroad spike, hardened, sharpened and finished with walnut handle slabs. The second photo is a set of hori hori that I made for the Nikka Yuko Japanese Gardens in Lethbridge, AB. It was a great learning experience for me, and looking at the older photo now I can see both how my design has changed over time, and how my ‘smithing has changed.
The big, iron block is a 250 lb. Japanese pattern anvil I purchased from my friend and mentor, Dave J Friesen of Crossed Heart Forge. Using that, and an eight pound hammer, has really increased my efficiency. There’s quite a bit of material to move in the spike. It’s a mid carbon steel so it’s not as tough as spring steel, but it starts out at 5/8″ thick, and I forge that down to 5/32″ at the hilt of the blade with a slight thickness taper to the point. Two holes are drilled in the handle for steel pins to secure the handle slabs.
The serrations have seen some modification over the years, too. For the Nikka Yuko hori hori, I used a half round file but it seemed to me the teeth were too shallow and didn’t saw very well. I then switched to a small chainsaw file for the knives made from coil spring, and that worked ok but I think the teeth were a bit small. The serrations, according to my research and personal experience, are designed to saw through woody materials such as thick roots and small branches. The latest iteration uses a large chainsaw file for deeper teeth which should make for quicker cutting and sharpening (less teeth to sharpen).
The scooped blade is formed by forging into a shallow piece of pipe, cut in half. The first railroad hori hori knives had a very slight scoop by forging with a round peen along the length of the blade. I leave the scale from forging on the blade as it inhibits rust, and it wears off over time anyhow because of digging in the soil.
The blade and handle are hardened in room temperature vegetable oil. This gives a hardness a bit below an axe, and allows for quick field dressing with a bastard file and chainsaw file if needed. There’s no need to make the edge razor sharp as the first stab into soil acts like sandpaper. The balance between hardness and toughness is important; it’s hard enough so that sharpening isn’t required too frequently, while remaining tough so the knife doesn’t snap when prying a plant out of the ground.
The handle is a simple affair: two slabs of walnut, or whatever scrap hardwood I have lying about, pinned with two steel rivets. A woodworking tool that I love to use ever since Dave J showed me is the Japanese saw file. It works quickly and leaves a finish that needs only light sanding to smooth out. The bevels on the handle are formed with that saw file. A coating of linseed oil seals and protects the wood.
After discussing the sheath design with my wife and striker, Lorinda, I decided to try a cross carry instead of the traditional wooden sheath or vertical sheath that’s common with factory models. The cross carry keeps the handle out of the way when bending over or kneeling, which is a very common stance in the garden. The vertical carry can make drawing the knife a bit awkward, and these knives are easily misplaced if not kept near at hand. This is an experiment at this point, but I really like how it came together.
The leather sheath is fitted to the scooped blade to ensure a snug fit while preventing the edges from slicing up the inside of the sheath. Copper rivets secure the belt loop and the sheath itself. I thought about using copper rivets on the handle, too, but decided on steel for the extra strength they provide.
I look now at the requirements for a good hori hori knife and I realize I picked a really hard tool to start with. Back in 2016 I had only been a hobby smith for about a year. The hori hori has a difficult blade shape, two sharpened edges, and needs just the right balance of hardness and toughness. I ruined a good number of promising knives when they warped after quenching and tried bending them back. Pretty sure the neighbours heard my dismay when the blade went <snap>! Other times I would spend an hour or more heating up a warped blade, forging it straight, normalizing it and quenching once again… only to have it warp again. Thankfully, I can say that no one who has purchased one my knives have had them break or bend, which is a common complaint about the factory models.
I’m looking at trying my hand at other hand tools, now that I have a good number of years of experience under my belt. Wood carving knives, draw knives and broad axes are next. Hopefully I can make at least one of each this year and see where that takes me.