SAE AS 28431 pdf download

SAE AS 28431 pdf download.Aerospace Signaling Torque Wrenches.
This Society or Automotive Engineers (SAE) Aerospace Standard covers requirements for micrometer adjustable, feel impulse, torque wrenches. The torque wrench is used to apply a pre-set torque to threaded fasteners and other torque requirements.
1.2 ClassifIcation:
Torque wrenches covered by this specification shall be one of the following types and classifications, as specified.
Type I Bi-directional torque wrench
Class 1 Non-ratchet head (precise clockwise torque)
Class 2 Ratchet head (precise clockwise torque)
Class 3 Non-ratchet head (precise counter-clockwise torque)
Class 4 Ratchet head (precise counter-clockwise torque)
Class 5 Changeable head (precise clockwise torque)
Class 6 Changeable head (precise counter-clockwise torque)
Type II Uni-directional torque wrench
Class 1 Non-ratchet head (precise clockwise torque)
Class 2 Ratchet head (precise clockwise torque)
Class 3 Non-ratchet head (precise counter-clockwise torque)
Class 4 Ratchet head (precise counter-clockwise torque)
Class 5 Changeable head (precise clockwise torque)
Class 6 Changeable head (precise counter-clockwise torque)
1,2.1 Class Accuracy: Type I bi-directional torque wrenches shall have an accuracy of ±4% in the precise torque direction, and ±6% in the opposite direction. Type II uni-directional torque wrenches shall have an accuracy of ±4% in the precise torque direction, and shall not signal in the opposite direction.
1.2.2 Accuracy: Torque accuracy is defined as the difference between the applied torque and the preset torque divided by the pre-set torque expressed as a percentage.
2. APPLICABLE DOCUMENTS:
2.1 The following documents form a part of this standard to the extent specified herein. Where conflicts occur between this standard, and specified documents, this standard shall take precedence.
2.1.1 SAE Publications: Available from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001, AS4984 Coating Requirements for Aerospace Hand Tools
2,1.2 ASTM Publications: Available from ASTM, 100 Barr Harbor Drive, West Conshohocken, PA
19428-2959.
ASTM E 18 Rockwell Hardness and Rockwell Superficial Hardness of Metallic Materials, Standards Methods of Test for
2.13 ASME Publications: Available from ASME, 22 Law Drive, Box 2900, Fairfield, NJ 07007-2900.
ASME B107.4 Dflving and Spindle Ends for Portable Hand, Air, and Electric Tools
ASME B107.1OM Handles and Attachments for Hand Socket Wrenches – Inch and Metric Series
ASME B107.17M Gages, Wrench Openings, Reference
3. REQUIREMENTS:
3.1 Torque Wrench:
The torque wrench shall have an accurate micrometer-type, presetting mechanism upon which the required torque can be hand set by adjusting the mechanism. The torque wrench shall have a locking mechanism which holds the pre-set torque securely during use of the torque wrench. Operation of the pre-setting mechanism and locking mechanism shall not require the use of tools or equipment, The torque wrench shall have a torque signaling device that meets the requirements of 3.3.7.
3.2 Illustrations:
The illustrations herein are descriptive and are not intended to preclude the purchase of torque wrenches otherwise conforming to this specification.
3.2.1 Torque Wrench – Class 1 and 3: Class I and 3 torque wrenches shall be similar to Figure 1:
except 500 to 2000 ft-lb capacity torque wrenches similar to Figure 2.
3.2.2 Torque Wrench – Class 2 and 4: Class 2 and 4 torque wrenches shall be similar to Figure 3.
3.2.3 Torque Wrench – Class 5 and 6: Class 5 and 6 torque wrenches shall be similar to Figure 4. Changeable heads shall be similar to Figure 5. however, connection configurations can be different than illustrated.
3.3 Design, Materials and Construction:
The torque wrench design, materials and construction shall be of uniform high quality adequate to meet the requirements of this specification and capable of providing repeated accuracy over an extended service period.
3.3.1 Handle: The torque wrench shall have a metal handle of one-piece or multi-piece design using a threaded or other mechanically fitted joint. A suitable portion of the handle shall be knurled, grooved, ribbed or provided with a non-toxic rubber cover that facilitates turning of the adjustable portion of the handle.
3.3.2 Drive Requirements Classes 1. 2. 3, 4: Torque wrenches of dasses 1 through 4 shall have a male square drive with a spring-loaded steel ball which conforms to the requirements of ASME B 107.4, and shall be tested in accordance with 4.11. The spring-loaded steel ball shall be located as shown in Figure 1. The male square drive hardness shall be Rockwell C 34 to 54, and shall be tested in accordance with 4.11.1. On non-ratcheting torque wrenches, two opposite flats of the male square drive shall be parallel within 5 degrees of the longitudinal axis of the torque wrench.