Dressing stone with a hammer and chisel, and a thumb
Most of the stone I use is laid as it comes, because a dry-stone wall wants the stone’s natural faces and because every blow of a hammer is time not spent building. But some pieces need a corner knocked off, a face flattened or a length split, and learning to do that cleanly has been a slow, occasionally painful education.
The tools are few: a walling hammer of about 1.3 kilograms with one flat face and one blunt edge, a heavier club hammer, a steel chisel about 25 millimetres wide for pitching, and a pair of safety glasses that I now wear without fail after a chip from a flint-hard pebble in the sandstone hit me just under the eye. Gloves save the skin but take away the feel of the stone, so I wear them for lifting and take them off to dress.
Sandstone, which is what the field wall is made of, has a bedding, the layers it was laid down in, and it splits along that bedding far more willingly than across it. To take a slice off, I find the bedding by eye, score a line along it with light taps of the chisel all the way round, then work round again hitting harder until the stone opens along the line. Done well, it goes with a dull click and two clean faces. Done impatiently, with one big blow, it shatters into three useless pieces and a lot of dust.
Knocking a corner off is pitching: the chisel is held at a shallow angle to the face, a finger’s width in from the edge, and struck firmly so that a flake jumps off. Working from the corner inwards in a series of flakes gives a straight edge. I practise on stones that are going into the hearting anyway, where a bad result does not matter.
The thumb. In October I was holding a stone steady on the block with my left hand while striking with my right, the hammer skidded off a wet surface and landed squarely on my thumbnail. The nail went black, then came off, and has only now grown back. The rule I broke, which the course tutor had said twice, is that the hand holding the stone goes nowhere near the line of the blow. The stone is held with a wedge or a boot, or it is placed so it needs no holding at all. The block I work on is a stout log cut to knee height, so the stone is at a comfortable height for both arms. Working off the ground is how backs get hurt, and I have been lucky on that front at least.