ASME B18.21.3:2008 pdf free download.Double Coil Helical Spring Lock Washers for Wood Structures.
Although these washers were designed speciFically for use on bolts in wooden assemblies (poles. cresslrms, etc.), they can also he used for general applications where a heavy duty double coil washer is needed.
2.2 DimensIons
The dimensions of standard and extended travel double coil helical spring lock washers for wood structures are specified in Tables I and 2 and are before coating. Selections should be made from standard or extended travel series in Tables I and 2, respectivel to suit design requirements.
2.3 MaterIal and Hardness
2.3.1 Material Composition. Viashers shall be made from material meetI1g the chemical composition requirements of the following standards:
(a) up to and including in. carbon steel — SAE j44)3 1055-1065 (UNS G10550-G 10650)
(b) 4 in. and above boron steel — SAE J41 I 10B55- 10B65
2.3.2 Hardness. All washer section hardness requirements are 38 HRC to 46 HRC. 372 H’.’ to 458 HV. To prepare washers for checking the material hardness, cut washer approximately in half so only one coil is used. Cold (water) grind or file both sides sufficiently flat and parallel to ensure a correct reading. If applicable, be sure to remove the dccarbunzed and coated surface. During this operation, care shall be exercised to prevent the surface temperature from exceeding 250’F. Refer to ASTM F 140 for hardness conversion.
2.3.3 Dca,bwlzatlon. Carbon steel and boron steel shall meet the limits for decarburization shown in Table 3. The method for testing limits shall conform to
SAE J419.
2.4 Washer Section
The corners at the inner and outer penphenes of the washers shall be slightly rounded. The section of the fmishcd washer shall be slightly trapezoidal with thickness at the inner periphery greater than the thickness at the outer periphery by a minimum of 0.0005 in. to a maximum of 0.001 in. per 0.01% in. of the section width. The minimum section thickness specified in the dirnensional tables represents the nominal mean thickness, of the trapezoid. The tolerance on the nominal mean thickness of the trapezoid shall be subject to the following:
2.5 Coiling
Washers shall be coiled so that the gap between coilsshall be such as to prevent washers from linking.Thesevered ends of the washers are to be cut so that theends are less then two full coils as shown in Tables 1and 2, dimension C.
2.6 Workmanship
The flat surfaces (faces) of the double coil helicalspring lock washers shall be free from such surfaceimperfections as knurling, serrations,die marks, deepscratches, Ioose scale, burrs, or other irregularities thatwould affect serviceability. Moderate feed roll marksshall be permissible on the outer periphery.
2.7 Grinding
The face on both severed ends of the washer shall beground prior to heat treating to provide a flat surfaceon each side as shown in Tables 1 and 2, dimensions Dand F.
2.8 Finish
All washers shall be mechanically coated and shallmeet a minimum of 1,500 hr to red rust when tested inaccordance with ASTM B 117.
ASME B18.21.3:2008 pdf free download
