Making ropes

Let us begin with the basic principles of rope construction. A laid rope normally consists of several strands—most commonly three or four—and each strand is formed from a number of yarns. Rope is made on a ropewalk or rope-making machine, which maintains controlled twist and tension throughout the laying process.

We will use a vertical rope-making machine to lay three-strand rope. The notation N × 3 will therefore be used below, where N is the number of yarns in each strand.

The machine twists the yarns in each strand in one direction, while the complete rope is laid in the opposite direction. In a vertical setup, a suspended weight provides the tension, while the installation height governs the available working length and therefore the maximum length of finished rope.

The diameter of the finished rope therefore depends primarily on two parameters:

– the diameter (or linear density) of the yarn used

– the number of yarns in each strand

The calculator below provides an APPROXIMATE finished diameter based on these parameters and suggests a yarn arrangement for laying three-strand rope from the selected thread types.

The procedure is as follows:

• Prepare the required yarns according to the number needed in each strand, allowing extra length for contraction during twisting and laying.

• Prepare a fine thread of the same colour for whipping the ends of the rope to prevent it from unlaying.
• Run the yarns between the rope-making machine and the suspended weight. Make sure that the weight hangs freely and that all yarn groups are tensioned evenly. Adjust the weight if necessary.

• Position the laying top at the lower end of the future rope, close to the weight.

• Begin turning the crank of the rope-making machine. The yarns will twist into strands and, after sufficient twist has built up, the suspended weight will begin to rotate in the opposite direction, laying the strands into rope. At this point, reduce the crank speed until it is approximately equal to the rotational speed of the weight.

• As the rope closes, the laying top will begin to travel upwards along the strands. Monitor the firmness and evenness of the lay, and guide the top by hand if necessary.

• Once laying is complete, whip both ends of the finished rope with fine thread. Only then should you remove the rope from the machine.

Important notes:

– The calculated rope diameter is only a guide. The actual diameter depends on several factors, including the type of thread, the suspended weight, and the rotational speed of the mechanism. I therefore recommend making a short test length first and correcting the calculation on the basis of an actual measurement.

– Lightly dressing the finished rope with beeswax is a useful final step: it lays down loose fibres and makes the rope more resistant to handling. – When cutting the rope into shorter lengths, secure it on both sides of the intended cut BEFORE cutting. Thread—especially synthetic thread—is prone to unlaying.

– Keep in mind that the length of the finished rope will be approximately 30% shorter than the length of the material used to make it. In other words, if you want to produce a 50 cm rope, your starting material must be at least 72 cm long. Accounting for the weight and the allowance for twisting, the distance from the mechanism’s clips to the floor should be at least (desired length / 0.7 + distance between the mechanism’s clips + height of the weight). For the device shown in the illustration, the distance between the clips is 6 cm, and the height of the weight is 7 cm.