Double Loop Binding Wire - How it Works

Double-loop spirals are produced "open" to be successively inserted in pre-punched holes of the product and then closed.

The main operations in the binding process are:

  1. Selection of the size of the spiral, the pitch and the number of holes.
  2. Punching of the sheets.
  3. Cutting of the spiral from the main spool in the required length and number
  4. Inserting of the spiral (and for calendars of the hook)
  5. Closure of the end product

  6. Those operations can be performed in different ways, from small hand operated machines, up to big automatic or semiautomatic solutions: Rilecart is currently the company offering to the market the widest spectrum of machinery type.


    • The first step is to choose the diameter of the spiral according to the thickness of the product to be bound and the machine being used. In order to ensure smooth turning of the pages, it is important to leave a gap between the spiral and the product being bound. The size of the gap is determined by the type of binding machine used.

    • The pitch is the number of rings that can fit in one inch (2,54 cm), for example a 3:1 pitch means that there are three rings in each inch (one every 8,46 mm). In the case of diameters up to 9/16, the standard pitch used is 3:1, whist for bigger diameters a 2:1 pitch is available. The 4:1 and 9:16 pitches, used or smaller diameters are nowadays obsolete.

    • Once selected the diameter, the punching of the sheet takes place. If a manual machine is being used, the pitch is critical whereas the dimension of the hole is o lesser importance.
      With higher end machinery, it is also necessary to select the correct dimensions for the hole. There is a predefined correlation between diameters and hole size which can be check in the appropriate reference table.
      For the choice of round or square holes, the latter facilitates the insertion of the spiral and as such is the most commonly used though the choice can also depend on aesthetic criteria.

    • Following this, the cutting of the spiral takes place. If automatic or semi-automatic binding machines are being used, this operation is automatically performed from the original reel. If, on the other hand, a manual machine is being used, it is possible to manually cut the reel, use a specific spiral cutter or it is possible to buy boxes of cut to size spirals directly from us.

    • The insertion of the product and its closure complete the process. This can be done by industrial machinery semi automatically or manually with simpler pressing machines.