A foot ring, a bevel and the discipline to stop: trimming is where a thrown form becomes a pot that sits properly and feels made.
Trimming gets about a tenth of the attention throwing gets, and it is the difference between a pot that sits like a pot and one that sits like a lump. It is also the stage most people skip, because it happens when the work is no longer impressive and the wheel has gone quiet.
I like trimming. It is the only part of the process where the piece is already safe on the shelf and nothing can be lost by thinking. The form is decided. All that is left is the foot, the weight and the line.
Leather-hard is a window, not a mood
The clay must be firm enough to hold its shape under a tool and soft enough to cut cleanly. Press a thumb in; the dent should stay with a crisp edge rather than a smear. Too soft and the tool drags, the rim deforms, and you chase the wall around the head. Too hard and the clay dusts and chips.
If the window has closed, do not force it. Wrap the piece in a damp cloth overnight and try again in the morning. A rushed trim is obvious from across the room, and sanding later only partly disguises it.
A chuck that holds without gripping
Trim upside down, on the rim, in a chuck or on a pad of soft clay. The rim is carrying the weight, so the chuck has to support the shoulder rather than squeeze the lip. A coil of clay pressed into a ring works. A plaster hump carved to the profile works better. What does not work is centring the piece by eye and hoping.
Tap the wheel head before you start. If the piece rocks, re-seat it. A wobble at this stage becomes a foot ring on a slant and a pot that limps on the table for the rest of its life.
The foot ring is a decision
A foot is not decoration. It lifts the base off the table, gives the hand somewhere to hold, and stops the glaze pooling into a puddle at the bottom edge. I cut a narrow ring, wide enough for a thumb, and leave the centre of the base slightly rough so it grips the shelf.
Shape matters more than depth. A hard vertical edge reads as factory work. A soft bevel, cut in two passes with the loop tool at a shallow angle, reads as a person. The tool wants to be sharp and the passes want to be light; a dull loop tears the clay and a heavy hand goes through the base.
Dust, and the rest of the bench
Trimmings come off fast and dry quickly. Brush them into a bucket rather than onto the floor, and keep a sponge for the rim so it does not harden while you work. The same slip can be wedged back into a bag once it is dry enough, though I keep it separate from fresh clay rather than pretend it is the same.
Knowing when to leave it
The temptation is to keep going, to take one more shaving, to make the line perfect. Every extra pass thins the base and brings the piece closer to the shelf of shame. When the ring is even, the bevel is clean and the piece sits without rocking, stop. Sign it and cover it.
Trimming rewards restraint more than skill. A good foot is one you do not notice until you pick the pot up, and then it is the only thing you notice.