Fig. 684.
To test a straight-edge, mark a line by it, then turn the straight-edge over and see if it still coincides with the line, or mark another line and see if it coincides with the first one. Try your straight-edges by this test once in a while, as they are liable to become crooked. In turning the edge over, however, do not reverse the ends, as in case of an undulating curvature the curves may agree and give you the impression that the edge is straight when it is not. In the first case shown in Fig. 684 (exaggerated) this would not happen, but in the second case (also exaggerated) it might. See Marking.
Strop.—A piece of hard, smooth leather on which to strop your tools you can easily procure. It can be fastened on a piece of wood (see page 85). Spread on it a paste of sweet oil and emery, lard oil and crocus powder, or some similar preparation. A pine board on which "air-dust" has accumulated can even be used. See remarks under Sharpening.
Tacks.—Tacks are sold as one-ounce, two-ounce, and so on according to size.
Do not use tacks for fastening wood to wood, but only for fastening leather or cloth or the like to wood. The pointed wedge-shape of the tack tends to split thin wood, and is not at all suitable to fasten two pieces of wood together, particularly in thin wood or near the edge. Possibly you may have seen some disastrous results from the attempt to tack pieces of wood together.
Tape-Measure.—This article (preferably of steel) is often useful, though not nearly as important for an amateur to buy as many other things.
Tenon.—See Mortising.
Tenon-Saw.—See Saw (Back-Saw).
Tool-Racks.—See page 83.
Toothed-Plane.—See Plane.