MTS Series 646 Hydraulic Collet Grips - Manual (Page 60)

Series 646 Hydraulic Collet Grips 60 Operation
Installing a Threaded Specimen
To load a threaded specimen into the grips:
Prerequisite
This procedure assumes that the preload platen is installed and the proper collet
has been selected for the specimen being tested.
Procedure
1. Adjust the hydraulic grip supply pressure to the minimum level.
2. Select system force control in the most sensitive range available.
If you use displacement control during specimen installation, you can cause
specimen damaging forces.
Be very careful when manually adjusting the actuator in displacement control
because the actuator will move to reach any command regardless of anything
being in its path.
If only displacement control is available, use extreme care not to apply
specimen-damaging forces in the following steps.
3. Release both the upper and lower grips.
4. Using a spanner wrench, thread the selected collet assembly into the upper
grip. Ensure that when the collet retainer is threaded fully into the grip
housing, the alignment markings on the collet retainer and grip housing are
aligned.
5. Thread the specimen into the upper grip until it is snug against the preload
platen. Lock the upper grip. Count the number of exposed threads on the
specimen.
CAUTION
Specimen
Threaded
Insert
Collet
Retainer
Preload
Platen