MTS Axial Extensometers - Manual (Page 33)

Configuration 33
Knife edges are available in the standard size, in a heavy duty size, and
in an extended length size. The heavy duty and extended length knife
edges are approximately twice as thick as the standard ones. To
maintain the proper gage length, the contact edge is off center. Heavy
duty and extended length knife edges also require special knife edge
hold-downs or special attachment adapters for quick attachment springs.
Extended length knife edges provide more clearance between the
specimen and the ends of the extensometer arms.
Excessive torque on the extensometer arms can damage the
extensometer.
The extensometer arms can be damaged when mishandled.
Do not hold the extensometer case when loosening or tightening the
socket head cap screws. Use an adjustable wrench to hold the
extensometer arm or attachment adapter. Loosen or tighten only those
socket head cap screws on the arm being held with the wrench.
To change knife edges:
1. Zero the arms of the extensometer. Depending on the extensometer,
this can be accomplished using the zero pin, stop block, or a special
fixture.
2. Use a small adjustable wrench to grasp the upper arm or
attachment adapter.
Heavy Duty Standard
CAUTION
Hex Wrench
Adjustable
Wrench