The Right Tool for the Job
Two tools do most of the work in trimming: the loop tool and the trimming knife. Understanding what each one does (and when to use it) saves you from fighting your clay.
The Loop Tool
A loop tool has a small metal loop or ribbon at the end of a handle. The loop is a cutting edge on both the inside and outside of the curve.
- What it does: Removes clay in curling shavings, hollowing out the base and shaping the foot ring walls.
- Best for: The bulk of trimming: removing large amounts of clay efficiently.
- Feel: When sharp and used correctly on leather-hard clay, it produces satisfying curls and a smooth cut surface.
Loop tools come in different sizes and shapes: a wide flat loop removes clay fast, a narrow pointed loop gets into tight corners.
The Trimming Knife
A trimming knife (also called a fettling knife) is a thin, flexible blade. In trimming, it is used for:
- Defining the outer wall of the foot ring: Cutting a clean vertical line on the outside.
- Cleaning up edges: Removing tags and burrs from cut surfaces.
- Beveling: Cutting a small chamfer on the bottom edge of the foot ring.
Holding the Tool
For both tools, hold the handle firmly but not tensely. Your other hand steadies the tool by resting a finger or two against the moving clay; this acts as a brake and keeps the cut controlled. Never hold a trimming tool with only one hand unsupported.
Tool Prep Checklist
Before trimming starts:
- Confirm loop edge is sharp and clean
- Choose loop size based on cut area
- Set support hand anchor point
Prepared tools produce cleaner cuts and less chatter.
Go Deeper
Loop tools and trimming knives are specialised versions of the cutting tools used on a lathe, where a fixed blade shapes a spinning workpiece. The principle is identical: controlled contact between a sharp edge and rotating material. Shoji Hamada was known for his confident, minimal trimming style, often completing a foot ring in just a few passes with a single loop tool.
