Instron 2603-080 - Chapter 3: Operation; Adjustments and Settings; Specimen Clamp Position Adjustment; Specimen Gripping Force Adjustment

3-1
Chapter 3
Operation
• Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
• Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
• Calibration Verification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7
Adjustments
Horizontal Position of the Specimen Clamp Assemblies
The horizontal position of the specimen clamp assemblies can be adjusted to suit the
thickness of the specimen under test.
1. Release the thumbscrews holding the clamp blocks to the arms (see Figure 3-1).
2. Position the clamp blocks such that the knife edges are touching the rear face of the
specimen.
3. Re-tighten the thumbscrews.
Specimen Gripping Force Adjustment
The specimen clamp rods are spring-loaded. The gripping force can be altered using the
adjusting nut shown in Figure 3-1.
Adjust the clamping force so that:
• Applying the test force does not cause the specimen to slip on the grip, but
• Applying a sharp tug (simulating specimen break) releases the specimen from the clamp
rod and knife edge.
If you are using very large grips (wider than 119mm) and the required grip separation is
less than or equal to (gauge length+52mm) you can replace the thumb screws with the
supplied button head screws (part no. 204E116) to gain some space.
The minimum grip separation possible when using this extensometer is (gauge
length+40mm).