Pitches / Hole Patterns:  There are three common hole patterns used in Wire binding documents with double loop wire. Each hole pattern has specific sizes and applications where it is best suited. Here is a quick overview of the different options...

Wire 3:1 Pitch (3 Holes Per 1"): The three to one pitch hole pattern is most commonly used for wire binding small sized documents with double loop wire. Spines for wire binding are available in sizes between 3/16" and 9/16" in diameter. Three to one pitch wires are not available in sizes larger than 9/16". The size of the holes used with this wire binding pattern simply does not allow for larger spines to be produced. The hole pattern used for 3:1 pitch wire binding can use either square or round holes.

Wire 2:1 Pitch (2 Holes Per 1"): A two to one pitch / hole pattern is most commonly used for wire binding larger sized documents it can also be used for binding smaller diameter books. 2:1 pitch wire is most commonly found in sizes ranging from 5/8" up to 1-1/4". However, a couple of manufacturers make wire binding special small sized 2:1 pitch wire for binding documents as small as 1/4". The holes for this type of wire binding are normally rectangular but can sometimes be square or round depending on the manufacturer of the paper punching equipment that you use.

Wire Binding Process: Binding documents using the double loop wire binding involves just a few basic steps.

	Put together the document including covers and measure the document overall thickness to determine the correct size of wire binding element.
	Set up your wire binding machine so the holes are centered on your paper.
	Divide your document into appropriate sections and punch it using your wire binding machine or modular multipurpose binding punch.
	Place the pages of your document onto the U shaped wire binding elements by hanging them on it.
	After carefully arranging the pages of the document over to the wire binding closer, engage the machine to squeeze the element together until the U shape becomes an O shape- usually with a lever action closer although there are pneumatic systems out there.

 Wire Binding (twin loop / double loop) Equipment:  Binding documents with double loop / twin loop wire requires a binding machine including a wire closer. Low volume operators will often find a small less expensive manual wire binding machine that offers a manual hole punch and a built in wire closer to be adequate. Medium volume users will often require a wire binding machine with an electric punch that can or cannot include a wire closer, wire closer can always be separate. High volume wire binding users such as print shops, larger binderies,  and in-house printers will split the punching and final stages of the binding process (punching, hanging pages on the wire and closing the wire) wire in order to increase productivity. These users will often use a higher end heavy duty modular interchangeable die punch or an automated punching system along with either a manual or an electric wire closing machine.