The seemingly insignificant detail of the appearance of the side edge profile of a jaw crusher die has as much bearing on the performance of a jaw crusher as the tooth form or wear face design of the jaw die.

There are varying degrees of fully curved, straight, or straight with curved end profiles commonly available, as well as some specialty side profiles. Various side profiles can be used to “size” the jaw crusher to the feed material available. These are vertically symmetrical jaw dies that can be reversed top to bottom to optimize wear and more fully expend the part.

Fully curved jaws would be used when the crusher is larger than needed for the size of feed being introduced. With full curve jaws, the largest feed size wouldn’t exceed the dimension between the jaw dies just above the horizontal centerline of the crushing cavity. Rock larger than that horizontal dimension will then have its first “bite” taken at a point with a greater included angle, than what exists below that horizontal centerline. Slippage can occur with the larger feed and output reduced.

Straight jaw dies are best used when the feed blend is generally coarse with pre-scalping of fines and maximum feed opening of the crusher is required for the largest sizes of the feed material. Straight dies with a curved end are applied when the feed material includes a blend of enough volume of fines, that the end or toe of a completely straight jaw would wear off rapidly.

There are many variations of all these profiles, plus some specialty side profiles. Examples are asymmetrical cullet, tapered (thin to thick), tapered with curved ends, concave, convex, and more. Variations and cross combinations of any of these side profiles can be used to optimize crusher size to feed material. We have many examples of job designed jaw dies that were made and used specifically for particular sizing situations.