1. Spring back.
2. Eyelet and tape.
3. Sewed.
4. Rod.
5. Clamp which is screwed up tight.
The well known spring-back variety is, in principle, a semi-circular steel tube longer than the magazine to be held, to which board sides are attached. When the cover is closed the jaws of the steel are close together. In order to insert the magazine the covers are bent back toward each other. This opens wide the jaws and the magazine is slipped in. When the covers are released the steel tube is firmly fastened to the back of the magazine. This kind of binder is probably the easiest of all to adjust. It is, however, equally easy to remove, is clumsy and is harder to hold in the hand than others.
In the eyelet and tape class there are holes in the back of the cover. In fastening the magazine, tape or cord (generally a shoe string) is passed through the center of the magazine, laced into the eyelet and tied. The main objections to this kind of a binder are that it takes some time to fasten them and the magazine is generally loose in the binder when fastened.
Binders which require sewing have holes in the sides near the back. Instead, however, of passing the cord through the center of the magazine, holes corresponding to holes in the binder are punched directly through the magazine at the back, one near the head, one near the tail and another in the middle. The binder is then sewed on through these holes. The chief merit of these binders is that they are inexpensive; but it takes longer to attach them than other binders and the magazine is injured by the holes which have been punched.
There are various kinds of binders which use steel rods or bars through the center of the magazine. Some use one rather heavy rod which is hinged at one end, and hooked or fastened into a slot at the other end when the magazine has been inserted. Some have two or more thin steel rods hinged or pivoted at one end and held by a pin or a lock at the other end. And one at least has steel bars not permanently attached, the ends of which are in the form of a semi-circle, which are dropped between rigid uprights and prevented from slipping off by caps screwed on the uprights.
The writer knows of only two binders which use a clamp which must be screwed tightly in order to hold the magazine firmly. The great merit of these binders is that they hold the magazine firmly, so that it can by no possibility be removed except by the assistant who has the key. They are, however, clumsy and unduly large at the back and it takes some time to fasten them to the magazine.