There is a great lack of knowledge among workmen generally with regard to the tying of rope for scaffolding, and when it is considered that during the erection of a building the workman lives, as it were, on the scaffold, sometimes poised in midair and in other dangerous positions where life and limb is jeopardized, it is most essential that the scaffold should be trustworthy and safe, and one of the factors of safety is the correct lashing and tying of the rope, with the manipulation of which the workman should be perfectly familiar.
As a chain is no stronger than its weakest link, so stability of the scaffold is dependent to a great extent upon the security of its knots; hence the importance of knowing the best one to use for the purpose required. Although scaffolds are generally erected by qualified men, yet there are occasions when the workman requires some adjustment or addition to the scaffold for a special purpose. He has then to undertake the alteration himself, and his knowledge of tying knots can be applied.
The knowledge one possesses in tying knots is not confined to the one vocation of scaffolding, but is useful in all departments of everyday life. A great number of knots have been devised for various purposes. The few here illustrated are those chiefly used in the erection of pole scaffolding and comprise nearly all that are necessary. The tying of these knots should be practiced by the uninitiated, for the process is inexpensive, as the back of a chair may be utilized, a small piece or or two of sash cord, with a little persistence, being all that is required to make perfect.
A very good proof that the lesson has been learned thoroughly is to tie each of these knots in the dark. The principles of a good knot are its facility in tying, its freedom from slipping and its being easily untied, says a writer in an English exchange. All knots will jam more or less when subject to a strain. In the diagrams here given the knots are shown open before being drawn taut in order to show the position of the parts. The names usually given and their uses are as follows:
1. Bight of a rope.
2. Overhand, or thumb knot, to prevent a rope running through the sheave of a block.
3. Figure of eight knot, used as No. 2.
4. Stevedore knot; is useful when the rope passes through an eye. It is easily untied after being strained.
5. Square or reef knot; this is the most useful knot for joining two ropes of the same size. However tight it jams it is easily " upset " and undone.
6. Granny, or thief, knot; this should not be used, as it will jam tight but not slip (as erroneously supposed), will not " upset, " and consequently is difficult.
7. Single sheet bend,or weavers' knot; used principally for joining two ropes of unequal sizes more securely than a reef knot.
8. Double sheet bend; more secure than No. 7.
9. Carrick bend, for fastening the four guys to a derrick.
10. Flemish loop.
11. Slip knot.
12. Bowline, for making a loop that will not slip. After being strained this knot is easily untied. Commence by making a bight in the rope, then put the end through the bight and under the standing part, pass the end again through the bight and pull taut. This knot should be tied with facility by every one handling ropes..
13. Timber hitch; the greater the strain the tighter it will hold.
14. Clove hitch,consisting of two half hitches; used chiefly to tie ledgers to standards. This is the most useful of all the knots used in scaffolding on account of its simplicity and security.
15. Clove hitch, as No. 14, showing its application around a pole.
16. Round turn and two half hitches for securing a rope to a ledger, or for fastening the guys of derricks, shear legs, etc.
17. Fisherman's bend; used when a thick rope, such as a fall, is made fast to a ring.
18. Rolling hitch; used in a variety of ways, chiefly in making fast one rope to another that is held taut.
19. Sheepshank, for shortening a rope when the ends are inaccessible.
29. Catspaw, an endless loop, and used where great power is required.
21. Blackwaller; easily applied, but requires watching; has a tendency to slip.-" Carpentry and Building."