"Now let me show you a new trick," said Ralph. "It is always a good plan after making a drawing to write out a bill of material something like this:
| 1 pc. pine 14 × 8 × 1⁄2 | 1 pc. pine 6 × 2 × 1⁄2 |
| 1 pc. maple 14 × 6 × 1⁄2 | 4 11⁄4-inch f. h. screws |
| 1 pc. pine 8 × 11⁄2 × 7⁄8 | 5 3⁄4-inch f. h. screws |
"There you have in a nutshell all the items needed for the shooting board, and you can proceed to square all your pieces to these dimensions without consulting the drawing until you are ready to assemble the parts. The five 3⁄4-inch screws are for fastening the maple pieces to the flat piece of pine, and the 11⁄4 screws to fasten the cleats. All the holes for screws are to be bored and countersunk."
"What's countersunk?" asked Harry.
This led to a talk on screws and boring tools, and as it is valuable to the young worker in wood, we will give it as fully as possible.
Fig. 119. The use of screws
"There are several kinds of screws," began Ralph, "but the two most commonly used are flat heads and round heads. ([Fig. 119]). Flat-head screws are those we generally think of, but unless the hole which has been bored or drilled is reamed out at the top, countersunk as we call it, the screw head will stand out from the surface ready to tear your clothes and to scratch anything it may come in contact with, so you can readily see the importance of sinking them below the surface.
"On the other hand, there are often cases where we have no desire to hide the screw. The round heads are used for such cases, and because of their shape they do not catch hold of things. These screws are usually blued—treated with acid to give them a dull, more artistic colour. Screws treated in this way do not rust as readily as the bright ones. You can buy brass screws in both flat and round head forms; in fact you can get tinned, Japanned, lacquered, bronzed, copper, nickel, and even silver plated screws—if you have the money.