Torque Wrenches / Torque & Tension Testing Equipment
Torque wrenches are used in a variety of fastener tests such as:
- Torsional strength testing of tapping screws
- Drive torque testing thread rolling screws
- Hydrogen embrittlement testing electroplated screws and
- Prevailing torque, installation and removal torque, on
- torque, on lock nuts and lock screws
- Torque-tension testing tapping screws, lock nuts, lock
- screws, and structural bolts
Greenslade torque wrenches meet the accuracy requirement of +/- 1 %. A general rule is that torque wrenches should not be used in the lower 20% of their maximum torque rating.
Torque wrenches are available with either an easy-to-read, large dial face with a memory needle or a digital display. The digital wrenches can be connected to the Greenslade data collectors for recording test results.
Dial Torque Wrenches:
TWI-030; 6-30 inch pounds TWI-075; 15-75 inch pounds TWI-300; 60-300 inch pounds TWF-025; 5-25 foot pounds TWF-050; 10-50 foot pounds TWF-100; 20-100 foot pounds TWF-150; 30-150 foot pounds TWF-250; 50-250 foot pounds TWF-600; 120-600 foot pounds TWF-1000; 200-1000 foot pounds
Some fastener test specifications require that a bolt must achieve a given tension value when less than a maximum amount of torque is applied. When bolts are tightened in assemblies by applying torque they actually stretch and act like a spring to keep the components of the assembly firmly together. As a general rule, bolts should be tightened until their tension (stretching force) is about 50-60% of their minimum required tensile strength.
Tension cannot be determined with a torque wrench. The same amount of torque applied to bolts of the same size with different finishes will create entirely different tension forces. When tightening a bolt over 50% of the applied torque is used up in the under head friction. The only way to determine how much tension is created in a bolt is to test the bolts and nuts to be used in a Tension Tester. With this device plus a torque wrench, the Torque-tension relationship can be precisely determined. How much applied torque is required to generate a desired number of pounds of bolt tension can also be determined.
To test a bolt, it is inserted through the tester’s hydraulic load cell area and assembled into a nut. As the nut is tightened, the increasing bolt tension is shown on the tester’s pressure indicator.
TESTER MODEL S: Tooling: #6, #8, #10, 1/4 Tension capacity: 5,000 pounds TESTER MODEL J: Tooling: #10, 1/4, 5/16, 3/8, 7/16, 1/2, 9/16 Tension capacity: 30,000 pounds TESTER MODEL RL: Tooling: 5/8, 3/4, 7/8, 1, 1-1/8, 1-1/4 Tension capacity: 110.000 pounds