Making the Tool
In my travels through Korea, I’ve discovered some traditional Korean carving tools that are well suited to my process. The tool I use for carving is called a sanggam kal (鼻馬 蠔) and is used in Korea for inlay in the celadon tradition.
I make these tools using a specifically cut piece of spring steel. While I am still searching for a good local source for this type of steel, the best source I know of currently is in Korea. You may be able to find the same type at a sheet metal supplier and if so, they should be able to cut it to the specs you want.
I use ¼-inch, 18-gauge pieces of spring steel (1–2). You can also use a hacksaw blade, but because the hacksaw blade has been hardened during its manufacturing, you will need to heat it with a torch before you bend it.
To sharpen the steel, fit an angle grinder with a steel grinding flap wheel— a bench grinder works well too. This will cut through the material quickly and give you the specific shape you desire. Caution: Always wear both eye and ear protection when working with power tools.
Turn the grinder on and begin to taper one end of the steel piece into a point. Grind a bevel on all four edges of the newly shaped tip from where the steel piece starts to taper all the way to the tip and into a fine point (3).
Next, refine the ground end to remove any burrs. Do this by rubbing the beveled edges against a wooden table.
To form the carving hook, grip the tool and press the tip against the table to create a sharp, hair-pin, almost U-turn-like bend (4–5). This is easier to do on a wooden surface where the tip will stick a bit while you bend it and not slide or slip.
I find that the tool doesn’t yield the greatest quality lines until it has been used a bit. I often break the tool in by using it like a trimming tool on a piece of firm leather-hard clay for a few minutes.
Using the Tool
Grip the tool so that the hook has its sharpened side pressed up against the leather-hard clay. If the clay is too wet, it will be difficult to get a precise line. Pull the tool down, allowing the hook to remove material as you draw a line (6). Use more or less pressure depending on how accentuated you want the line to be. Clay may build up in the hook and need to be wiped clean periodically. As you clean it, remember that the hook is sharp.
The tools last (and continue to get better) until they break off. The amount of time depends on the character of the clay body being carved (soft vs. hard, smooth vs. grogged, etc.). I’ll usually go through a carving tip with every kiln load. The number of times I can re-grind the tip depends on the original length of the steel piece. I generally start with a piece that is about 10 inches long and can get 15–20 new tips out of that piece before it is too short to use. See Adam Field’s finished cups in image 7.
To see Adam make and use this tool, check out his Ceramic Arts Daily DVD Precision Throwing and Intricate Carving with Adam Field at, https://ceramicartsnetwork.org/bookstore/precision-throwing-intricate-carving.