Wherever wire rope transmissions are used it is necessary to splice the rope or cable so that it will run smoothly over the sheave wheels. For this purpose a long splice is invariably used. (Taken from “American Wire Rope” published by American Steel and Wire Company). The tools required are a small marlin-spike, nipping cutters, and either clamps or a small hemp rope sling with which to wrap around and untwist the rope. If a bench vise is accessible, it will be found very convenient for holding the rope.

“In splicing a rope, a certain length is used up in making the splice. An allowance of not less than 16 feet for ½ inch rope, and proportionately longer for larger sizes, must be added to the length of an endless rope, in ordering. The length of splice relation to the diameter of the rope is approximately 50:1.”

This extra length is equal to the distance EE´ in Fig. 117. The additional length recommended for making a splice in different sizes of wire rope is as follows:

Fig. 117. Having measured carefully the length the rope should be after splicing and marked the points M and M´, unlay the strands from each end E and E´, to M and M´, and cut off the hemp center at M and M´.

Fig. 118. First. Interlock the six unlaid strands of each end alternately, cutting off the hemp centers at M and M´, and draw wire strands together, so that the points M and M´ meet, as shown.

Fig. 119. Second. Unlay a strand from one end, and following the unlay closely, lay into the seam or groove it opens, the strand opposite it belonging to the other end of the rope, until there remains a length of stand equal in inches to the length of splice EE´ in feet, e. g., the straight end of unlaid strand A on one-half inch rope equal 16 inches for 16 foot splice. Then cut the other strand to about the same length from the point of meeting, as shown at A.

Fig. 119. Third. Unlay the adjacent strand in the opposite direction, and following the unlay closely, lay in its place the corresponding opposite strand, cutting the ends as described before at B.

The four strands are now laid in place terminating at A and B, with eight remaining at M and M´ as shown in Fig. 119.

It will be well after laying each pair of strands to tie them temporarily at the points A and B.

Fig. 120. Pursue the same course with the remaining four pairs of opposite strands, stopping each pair of strands so as to divide the space between A and B into five equal parts, and cutting the ends as before.

All the strands are now laid in their proper places with their respective ends passing each other.

All methods of rope splicing are identical up to this point; their variety consists in the method of securing the ends.

Fig. 121. The completed splice with ends secured results in a cable with scarcely any enlargement at that point. A few days’ use will make it difficult to discover at all.

The final part of the splice is made as follows:

“Clamp the rope either in a vise or with a hand clamp at a point to the left of A (Fig. 119), and by a hand clamp applied near the right of A open up the rope by untwisting sufficiently to cut the hemp core at A, and seizing it with nippers, let your assistant draw it out slowly. Then insert a marlin spike under the two nearest strands to open up the rope and starting the loose strand into the space left vacant by the hemp center, rotate the marlin spike so as to run the strand into the center. Cut the hemp core where the strand ends, and push the end of hemp back into its place. Remove the clamps and let the rope close together around it. Draw out the hemp core in the opposite direction and lay the other strand in the center of the rope in the same manner. Repeat the operation at the five remaining points, and hammer the rope lightly at the points where the ends pass each other at A´, B´, etc., with small wooden mallets, and the splice is complete, as shown in Fig. 121.”

A rope spliced as above will be nearly as strong as the original rope, and smooth everywhere. After running a few days, the splice, if well made, cannot be pointed out except by the close examination of an expert.

Fig. 122. If a clamp and vice are not obtainable, two rope slings and short wooden levers may be used to untwist and open up the rope.

Fig. 123. A marlin spike is absolutely necessary in order to separate the strands in making a splice in steel cable.

Wire Rope Drives

MINIMUM DIAMETERS OF SHEAVES FOR
POWER TRANSMISSION BY WIRE ROPES

(All Dimensions in Inches)

DIAMETER OF MINIMUM SHEAVES IN INCHES,
CORRESPONDING TO A MAXIMUM
SAFE WORKING TENSION.