ASME B18.21.1-2009 pdf free download.Washers: Helical Spring-Lock, Tooth Lock, and Plain Washers (Inch Series).
2.6 Coiling: Helical Spring-Lock Washers
ashers shall be coiled to form a helix. The gap arid relationship of the severed ends shall be such as to prevent washers from tangling and to ereiuw that washers compress flatly.
2.7 Processing: Helical Spring-Lock Washers
2.7.1 FInishes: Helical Spring-Lock Washers. Unless otherwise specified by the purchaser, luck washers shall be supplied with a plain (as-processed) finish, not plated or coated. Where corrosion preventative treatment is required. washers shall be plated or coated as specified by the purchaser. When helical spring-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 01)20 in. in excess of those specified in Tables I through 4 for minimum inside diameter and maximum outside diameter. Heavy coating of washers under / in. nominal size is not recommended.
2.7.2 Embrlttlement: Helical Spring-Lock Washers.
Electroplating carbon and boron steel-Jock washers is not recommended beca use of the possibility of hydrogen embrittlement failures. When the purchaser specifies electroplated lock-washers they must b baked after plating using times and temperatures suitable for relieving potentially trapped hydrogen All lots of electroplated luck-washers shall be tested by compressing them to a flat condition for a minimum of 48 hr. within which time they must not fracture. Compression shall be accomplished between parallel flat surfaces.
2.8 Workmanship: Helical Spring-lock Washers
The flat surfaces (faces) of helical spring-lock washers shall be free from such surface imperfections a. knurling. serration. die marks, deep scratches, loose scale, burrs, or other irregularities that would affect serviceability. Moderate feed roll marks shall be permissible on the outer periphery.
2.9 Twist Tests: Helical Spring-Lock Washers
The washer shall be gripped in vise jaws. The ends of the washer shall be free, and an axis passing through the skit 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 d/g with no sign of fracture.
3.1 Application: Tooth-Lock Washers
The tooth-lock washers covered in this Standard are intt-ndt-d for general application. The tooth-lock washers serve to increase the friction between the screw and th assembly. Internal tooth-lock washers are preferred where it is desirable to provide a smooth periphery.
3.2 Tooth Design: Tooth-Lock Washers
The selection of Type A or Type B tooth designs as shown in Fig. 3 and in Tables 6 through 10 shall be at the manufacturer’s option unless a specific design is designated by the purchaser.
The number of teeth, the length of the teeth, the width of the rim, and tht- thickness of the washer over the teeth (free height) shall be optional with the manufacturer. The prnfrctionoi the teeth on both sides of the washer shall be relatively uniform.
3.3 Styles and Dimensions: Tooth-Lock Washers
Dimensions for the various hpes of washers are as Follows; internal tooth-lock washers (Table 6). heavy internal tooth-lock washers (Table 7), external tooth-lock washers (Table 8), external tooth countersunk washers (Table 9), and internal/external tooth lock washers (Table 10).
3.4 Material and Hardness: Tooth-Lock Washers
3.4.1 Material Composition: Tooth-Lock Washers.
Washers shall be made from material meeting the hernical composition requirements of one of the following standards.