Used Rock-Crushers: 5 Questions to Ask

Dec. 16, 2014
Mellott_Company

Why does the same make and model crusher cost more from one dealer than another? Here are a five points to consider when you are “kicking the tires” on a used rock crusher.

Has the crusher been test-run before delivery?

In an imperfect world, machines sometimes fail. In the case of crushers, if they do fail prematurely it we see a tendency for this to happen within an hour of start-up. A repair facility that has a test stand can run the machine and, if it fails, troubleshoot the problem immediately, correct the issue and test-run again. The alternative is to use your plant as a test stand. If the machine fails on site, you might have to bring the crane back out and disassemble the crusher, ship it back for more repairs, bring it back, reassemble. This is all preventable by testing the machine before delivery.

Did the facility tear down the crusher?

There is no way of knowing the condition of a machine until it comes apart. There are areas of a stone crusher that no amount of testing will reveal, such as condition of bushings or seals that are only visible when the machine is disassembled. Damage from dirt, binding, shock load, and many others might be visible only when the machine has been properly disassembled.

Has the crusher been measured?

The ironic thing about rock crushers is that they are tough enough to munch on rock around the clock, they can forgive a piece of tramp-steel going through the chamber, but the insides of the machine have tolerances that are measured in thousandths of an inch. If those tolerances are off just a little bit, consequences can be very costly when lubrication doesn’t get to the proper places or components flex where they are not supposed to.

Was the main frame and main shaft checked for cracks?

These components are relatively expensive, both in terms of cost for the part and for the labor to replace. The forces that beat on these machines day in and day out provide the perfect environment for iron and steel to develop fatigue and stress cracks, sometimes finer that the naked eye can see. A cracked, expensive component is not good for anyone and should be remedied when the machine is in tear-down status. For crack detection to be accurate, paint, rust, and grease should be removed from the surface of entire part.

Is documentation performed?

Between test runs, tear downs, measurements, and crack detection, many different data points may be developed, both objective and subjective. A reputable test and repair facility should be able to provide a report with solid data to justify any of the repairs they recommend, like a $50,000 main-shaft replacement.

 

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