ASME B107.300-2021 pdf – Hand Torque Tools and Torque Testers.
6.2 ParaLLax Error — Category 14, Type I
The torque instrument scale shall be located so that it is in a horizontal plane. The pointer shall be adjusted to indicate zero when viewed from directly above the scale. The viewing plane shall be rotated 45 deg clockwise about an axis through the pointer and the apparent change in the relationship between the pointer and scale observed. The change shall not exceed 4% of the maximum graduated value.
6.3 Accuracy Tests — Category 14
(a) Test Equipment. Accuracy testing shall be performed on equipment capable of indicating torque applied with an accuracy of 25% or less of the accuracy requirement of the instrument under test. Interpolated readings of measuring equipment shall be made no more precisely than one-half of the smallest increment. Accuracy of the test equipment shall be independently verified by a route traceable to NIST. Testing shall be performed at a temperature not fluctuating by more than 2°F (1°C). This temperature shall be in the range of 64°F (18°C) to 82°F (28°C) (maximum relative humidity 90%) and shall be documented.
(b) TestPoints. Refer to the flowchart in Figure 6.3-1 as applicable.
(c) Load Position. All accuracy test loads shall be applied at the midpoint of the handgrip or designated load point in a plane perpendicular to the axis of the instrument drive tang. Flexible head instruments shall be tested in the unilexed position.
(d) Test Operation. Torque shall be applied at the appropriate place within the designated hand position until the instrument indicates and/or signals the target torque value. Immediately following the taking of the tester reading, torque shall be removed from the instrum ent.
(1) Type I, ClassesA, B, C, andD. The pointer or needle of the torque instrument shall be adjusted to indicate zero torque applied in the plane of operation before being mounted in the tester for any test sequence. Classes A, B, C, and D, Style 2 torque instruments shall have the signal device appropriately adjusted between each test operation.
(2) Type I!. The torque shall be applied at a rate sufficiently slow and steady so that after the release, the instrument will not over-travel causing the test equipment to indicate torque in excess of the release setting.
(3) Types III and IV. The torque shall be applied at a rate sufficiently slow and steady so that the torque at the point of release can be accurately read.
6.4 Accuracy Tests — Category 28
6.4.1 Torque Test. See the flowchart in Figure 6.4.1-1. All test loads shall be applied at the midpoint of the handgrip or at the marked load position for Types I and II and concentric to the handgrip for Types III and IV.
The test shall be performed on equipment capable of indicating torque applied within an accuracy of ±0.25% for Design A and ±1% for Design B at any point within the calibrated range of the torque instrument. Interpolated readings of the measuring equipment shall be made no more precisely than one-half of the smallest increment.
Accuracy of test equipment shall be independently verified by a route traceable to NIST.
6.4.2 Types II and IV AngLe Test. At the conclusion of the test in para. 6.4.1, the torque instrument shall be tested per the flowchart in Figure 6.4.2-1. All recorded measurements shall be within the requirements of para. 5.10 for Category 28, Type II instruments. The test shall be performed on angle-testing equipment capable of accurately measuring 0.5 deg (or better) and shall be independently verified by a route traceable to NIST.
6.5 Accuracy Tests — Category 29
6.5.1 Measuring Equipment. The accuracy of measuring equipment shall be at least four times better than the accuracy of the unit under test. Accuracy of measuring equipment shall be independently verified by a route traceable to NIST.
6.5.2 Test Sequence. See the flowchart in Figure 6.5.2-1.