The carpenter employs _gimlets_ for making holes for screws and nails. The gimlet is a short rod of steel, finished at one end into a sharp-pointed screw of one or two turns only, which, acting on the principle of that mechanical power, compels the tool to sink deeper and deeper into the wood, as the tool is turned round: and to enable the workman to turn the gimlet, it is fixed into a cross handle, which, acting as a lever, allows the friction of the tool to be overcome. Just above the screw point, the rod or shaft of the gimlet is _fluted_ or hollowed out: the sharp edges of this fluted part cut the hole made by the screw end larger and smoother, and the hollow receives the chips or shavings cut off, and prevents them from clogging the hole and stopping the progress of the tool. _Augers_ are large tools shaped like a gimlet, and, acting in the same manner, are employed for making large holes for bolts, spikes, &c. _Centre-bits_ are steel tools of different shapes made to fit into a bent handle something like the letter G, which, acting as a lever, allows of the tool being turned round and round by one hand, while by the other the workman holds the top of the handle steady and vertically over the point of the tool. Some of the _bits_ or tools are for cutting out cylindrical holes, and are shaped at the cutting-edge like a chisel, with a small point projecting from the centre of the edge, on which the instrument turns in the wood and acts on the principle of a lathe. On each side this point, the chisel-edge is bent sideways in opposite directions, to allow of its _ploughing_ up the wood before it with greater efficacy than it would do if it were not so formed. The _brad-awl_, or _nail-piercer_, is a short steel wire, sharpened at the point into a flat chisel-edge, and put into a plain turned handle. This edge being pushed into the wood, and the handle turned round, the tool divides the fibre, and makes its way on the simple principle of a wedge, and does not cut away or remove any portion of the material, as the above-described tools do. The carpenter uses nails and screws to fasten the different parts of his work together, and it is necessary to make a hole to receive them before they are driven in, or else the wood would split by the action of forcing the nail or screw into the solid material, and, indeed, it would be impossible to force a screw into the solid wood at all. The screw is forced into the wood by being turned round and round by means of a blunt chisel, called a _screw-driver_, the edge of which is inserted into a notch cut in the head of the screw to receive it. The Glue employed.