No. 37. Double bend—useful where a small rope is bent on to a larger. The end of the rope is given one extra turn round the bight of the other, with the consequence of a great increase of strength.
No. 38. Fisherman’s knot.
No. 39. Lark’s head, fastened to a running knot.
No. 40. Where increased strength is required a small rope can be attached to a larger one by means of a rolling hitch. The whole arrangement comes apart as soon as the strain is removed.
No. 41. A method of lifting scaffold poles in a vertical position by the use of the timber hitch and half hitch. If it is required to free the upper end while the pole is being carried, the half hitch can be replaced by a cord tied round the pole and the lifting rope.
CHAPTER VI
SCAFFOLDING ACCESSORIES AND THEIR USE
Ladders.—A ladder consists of a pair of sides connected by a series of oak or ash treads or rungs. The sides of long ladders are formed by cutting lengthwise a straight fir pole into two pieces. Short ladders are made with square sides, but they are heavier and, as the grain seldom runs continuously throughout their length, also weaker.
The pole for the sides is selected for its straightness of fibre, for a twisted pole cannot be sawn lengthwise without cutting across part of the grain, which as before stated is a source of weakness.
The pole has to be bored for the rungs, and this may be done either before or after it has been cut lengthwise. It is better to bore first, as then the holes occur at coincident intervals on each side; the rungs by this means are kept parallel and level.
The rungs are placed 9 inches apart, and are from 1 in. to 11⁄2-in. in depth in the centre, decreasing to 5⁄8-inch diameter at the ends. The ends of the rungs are painted with red lead before insertion, and any projections are afterwards cut off flush with the sides. They can be fastened at each end with wedges (see [fig. 63]), or pins of 1⁄4-inch diameter can be cut through the sides, as [fig. 64], to fix every fifth or sixth rung.