MTS Series 646 Hydraulic Collet Grips - Manual (Page 46)

Series 646 Hydraulic Collet Grips 46 Installation
The next step may apply a force greater than the force train capacity.
Exceeding the tensile load capacity of any element in the force train can
cause equipment damage or personal injury.
It is necessary to temporarily exceed the tensile load capacity; this is
accomplished by increasing the output pressure of the HPU.
6. Apply a static tensile force 10 to 20% higher than the maximum force to be
applied during testing.
If the spiral washers are not sufficiently tightened, the connector stud can
break when subjected to cyclic loads.
Improper preloading of the connector stud can subject it to cyclic loads
which can cause eventual fatigue resulting in connector stud failure.
Sufficiently tighten the spiral washers as described in the next step.
WARNING
WARNING