Vaulting poles should be round, very straight-grained, from air-dried (not kiln-dried) stock of light, strong wood, as spruce, free from knots or any cross-grained, weak spots. The thickness should of course depend on the length, but should not be less than 1¼" for an 8' pole (which is quite short), and the pole should taper toward each end (see Rounding Sticks).
Spring-Board.—A form not difficult to make is shown in Fig. 272. The framework can be made of any strong wood, but the spring-board itself should be of the best quality of clear, straight-grained white ash.
Before beginning work read carefully Marking, Rule, Square, Saw, Plane, in [Part V]., and look up any other references.
Fig. 272.
First make the base or framework. Get out two pieces of 2" × 3" plank for the outside pieces (to stand on edge) and screw blocks of the same plank at each end to raise the pieces from the ground as shown. Place these pieces so that they spread apart slightly at the forward end (Fig. 272), being about 22" apart at the rear end. Fit a cross-tie to connect these stringers at about 2' from the forward end.
Another cross-bar, resting on the stringers, is placed nearer the rear end, and about 1' from the rear end a piece of 3" × 4" joist is fitted between the stringers and held in place by a bolt passed through it and the stringers. This should be loose enough to allow the block to turn.
The spring-board can be made of five strips of 7/8" stock, 4" wide and 6' long, screwed to a cleat at the forward end, and securely bolted to the block at the rear end.
This apparatus can be finished as in the cases described above.