CDI Torque TORQUE SCREWDRIVERS - Manual (Page 7)

Page 4
INSPECTION
Inspect all wrenches repaired to determine that they are in an operational condition by
visually inspecting for worn, broken, cracked or damaged parts. Replace parts not found
to be in satisfactory condition.
ACCURACY VERIFICATION AND MINOR CALIBRATION PROCEDURE
This procedure is to be used to check the accuracy and, if necessary, perform a minor
adjustment on calibration. It must also be used after a major calibration.
There are two major international standards that establish torque wrench accuracy
requirements. They are ASME B107.14 Hand Torque Tools (American Society of
Mechanical Engineers) and ISO 6789 Hand Torque Tools – Requirements and Test
Methods (International Organization for Standardization). Both standards are recognized
as established accuracy test methods and referenced in this section. ASME and ISO
standards are subject to review and changes. The repair manual will be reviewed and
revised periodically but may not reflect the latest revisions of the specifications listed
above.
ASME B107.14
1. Preload the wrench by setting the wrench at 100% of full scale and operating three
times on the tester.
2. Reset handle to 20% of full scale. Take 3 readings at 20%.
3. Set and test the wrench three (3) times at 60% and 100% of full scale noting the
accuracy error for each reading. If the readings are within the accuracy requirements
for the direction (±6% or readings), no calibration adjustment is required.
ISO 6789
1. Preload the wrench by setting the wrench at 100% of full scale and operating five (5)
times in the direction of the test.
2. Reset handle to 20% of full scale.
3. Test the wrench five (5) times at 20% noting the accuracy error for each reading. Set
and test the wrench five (5) times at 60% and 100% of full scale noting the accuracy
error for each reading. If the readings are within the accuracy requirements for the
test direction (±6% or readings), no calibration adjustment is required.