Abstract： ASME B18.21.3:2008 pdf download.Double Coil Helical Spring Lock Washers for Wood Structures. 2.5 CoIling Washers shall be coiled so that the gap between coils shall be such as to prevent washers from linking. The severed ends of the washers...

ASME B18.21.3:2008 pdf download.Double Coil Helical Spring Lock Washers for Wood Structures.

2.5 CoIling

Washers shall be coiled so that the gap between coils shall be such as to prevent washers from linking. The severed ends of the

washers are to be cut so that the ends are less then two full coils as shown in Tables 1 and 2, dimension C.

2.6 Workmanship

The flat surfaces (faces) of the double coil helical spring lock washers shall he free from such surface imperfections as knuriing, serrations, die marks, deep scratches, loose scale, burrs, or other irregularities that would affect serviceability. Moderate feed roll marks shall be permissible on the outer petipher

2.7 GrInding

The face on both severed ends of the washer shall be ground prior to heat treating to provide a flat surface on each side as shown in Tables 1 and 2, dimensions 0 and F.

2.8 Finish

All washers shall be mechanically coated and shall meet a minimum of 1,5(a) hr to red rust when tested in accordance with ASTM B

117.

2.9 Twist Test

To prepare washers for twist testing, cut the washer approximately in half so only one coil is used. The washer shall be gripped in vice jaws. The ends of the washer shall be free, and the axis passing through the slot shall be parallel to and slightly above the top of the rjce so that less then 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 that at least 25% of the washer is exposed when twisting, as shown in Fig. 1. The edges of the wrench

jaws shall be in a plane parallel to the vice. Twisting the wrench increasing the free height of the washer section between S5 deg and 95 deg shall show no signs of fracture.

2.10 Travel

Travel shall be measured by placing the washer between hardened steel plates, one of which is move- able, until the washer is being touched by both plates. From this point, measure the distance required to completely close the washer. Minimum travel requirements are shown in Tables 4 and 5.

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