ASME B18.21.1:1999 pdf free download.LOCK WASHERS (INCH SERIES).
2.7 Processing
2.7.1 Finishes. Unless otherwise specified by the purchaser. lock washers shall be supplied with a plain (as processed) finish, not plated or coated. Where COCFOS1Ofl prCVeflLaLiVC treaLment is required, washers shall be plated or coated as specified by the purchaser. When helical spctng-lock washers are to be furnished with coatings over 0.0005 in. thick and are to be used with bolts or screws also having thicker coatings, they are to be coiled to limits of 0.020 in. in excess of those specified in Tables I through 4 for minimum inside diameter and maximum outside diameter. Heavy coating of washers under 4 in. nominal size is not recommended.
2.7.2 Embrittlement. Carbon and boron steel-lock washers that are electroplated or coated may be subject to embnttlemeni and shall be suitably treated to mini. mize such embrittlemeni. Plated washers shall not fracture after having been compressed fiat for a minimum of 48 hr.
2.8 Workmanship
The fiat surfaces (faces) of helical spring-lock washers shall be free from such surface imperfections as knurling. serratious, die marks, deep scratches, loose scale, burrs, or other irregularities that would affect serviceability. Moderate feed roil marks shall be permissible on the outer periphery.
2.9 Twist Tests
The washer shall be gripped in vise jaws. The ends of the washer shall be free, and an axis passing through the slot shall be parallel to and slightly above the top of the vise so less than 50% of the washer is gripped. A 90 deg maximum segment of the free end of the washer shall be gripped in wrench jaws so at least 25% of the washer is exposed when twisting, as shown in Fig. 2. Edges of the wrench jaws shall be in a pLane parallel to the vise. Movement of the wrench that increases the free height of the spring-lock washer shall twist carbon steel, boron steel, and alloy steel washers through an angle approximating 90 deg. and corrosion resistant steel and nonferrous washers through an angle approximating 45 deg with no sign of fracture.
3 GENERAL DATA FOR TOOTH-LOCK WASHERS
3.1 Application
The tooth-lock washers covered in this Standard are intended for general application. The tooth-lock washers serve to increase the friction between the screw and the assembly. Enternal tooth-lock washers are preferred where it is desirable to provide a smooth periphery
32 Tooth Design
The Type A and Type B tooth designs shall be
3.3 Dimensions
Dimensions of internal tooth-lock washers, heavy internal tooth-lock washers, externai tooth-lock washers, and irnernallexiernal tooth lock washers shall he as specified in Tables 6 through 10.
3.4 Mateilal and Hardness
3.4.1 MaterIal Composition. Washers shall be made from material meeting the chemical composition requirements of one of the following standards.
ASME B18.21.1:1999 pdf free download
