A review of our master parts catalog shows there are nearly 50 models of crushers in that approximate size range, with few likely sharing a common mainshaft eccentric stroke. Each manufacturer of these machines will incorporate their own eccentric geometry, relative to the depth of their crushing chamber, toggle position and length, power and speed chosen to run the crusher, and the overall stoutness of the crusher’s construction. With the variables that can be incorporated into a jaw crusher, we don’t believe a “standard” for eccentricity exists, except within a given manufacturers own standards. That is -- crusher manufacturers Cedarapids and Kue-Ken will have different views than Metso.

You’ve described a rather small crusher. Normal callout for crusher sizing is that the first number stands for the feed opening and the second number calls out the width. The smaller number generally comes first and identifies the feed opening, although several manufacturer and model exceptions exist. If you’re dealing with a specific model crusher, you’d best contact the manufacturer for their prescribed eccentric specifications.

To address your question as asked -- if one were to build a crusher with a 12.000-inch feed opening and a 7.000-inch width (not typical order of dimensions), the depth should be 30.000-inches minimum (creating an odd sized crusher), with an eccentric of 1.000-inch (2.000-inch stroke). That’s where we’d start with what we’ve seen. A good deal of the “action” of the crusher can be altered by the length and position of the toggle plate, relative to the chosen stroke.

There are a lot of variables that go into the design of a jaw crusher, and calling for a standard stroke for given sizes isn’t something that can be arrived at. Further discussion of your question would be in order to offer a more specific and relative answer.