The Sensuous Gadgeteer
(Page 10 of 11)
September/October 1973
By the Mother Earth News editors
Another good exercise for the ball peen hammer is to shrink one end of a copper plumbing fitting. Rest one end of the fitting on an anvil and tap firmly around and around on the end you want to shrink. Holding the anvil directly opposite the place you tap against gives the effect of hammering on the work from both sides at once. I once used this method for adapting a microscope tube to a new ocular.
RELATED CONTENT
CHISELS
A chisel is a knife that you move by tapping on it with a mallet instead of pushing it with your hand. A chisel, like any other knife, cuts by pressing the wood fibers together, not by prying them apart, except when large portions of material are to be removed. In this case dig a deep trench around the portion to be removed and split out the unwanted material by prying the grain apart. This method works on wood, which has a grain. It will not work on plastic, which has no grain. Plastic can and sometimes must be cut with a chisel or knife, especially when the plastic is stressed, but the plastic must always be shaved away in thin ribbons. Otherwise it will shatter. Essentially there are two kinds of chisel: the straight-edge chisel and the gouge.
The straight chisel is used for cutting out recesses in the shape of rectangular solids in wood, as for sinking a hinge into the edge of a door. The gouge cuts a trough out of a surface and can be used for the shaping of intricate curved surfaces.
The gouge is used for carving wood or for removing portions from wood surfaces. For example, if you want to remove a stained place in a wood floor and replace the stained wood, use a gouge to remove a lozenge-shaped hollow in the portion of wood around the stain. Then carve a block of wood to fit in the cavity in the floor. When the block nearly fits in the cavity, set it in the cavity and tap on it with the mallet. Then remove it. Some places will be shiny. These are the high spots. Sand them down and repeat the process until you are satisfied that the plug fits the hole well enough. Line the cavity with glue and place the replacement block in it, bracing it down by wedging a narrow board between the plug in the floor and the ceiling. Cover the ends of the board with cloth to protect the floor and the ceiling.
Gouges can be sharpened on specially shaped India stones that you can buy at big hardware stores. Sharpen your straight-edge chisels on a shop grinding wheel. The grinding wheel is usually a 4000 rpm (revolutions per minute) coarse carborundum wheel riding next to a small metal table that steadies the work.
When sharpening the chisel (or any other tool) on the wheel be careful to keep the tool moving. If the chisel stands still on the wheel the metal will heat up and lose its temper. If the metal gets a blue scorch on it you will know that it is ruined. The temper of metals is their springy quality which guarantees they will be strong without being brittle.
Temper (like the other formulas described here) is not fully understood but it is believed to be a function of the size, shape and orientations of the crystals in metals and alloys. Because temper is not understood, the formula for obtaining a good temper in a metal is discovered by trial and error. Such a formula, once found, is priceless, and lives have been taken in struggles to obtain formulas for well-tempered sword metal.
Page:
<< Previous 1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 | 10 |
11 |
Next >>
