Split Lock Washers: Dimensions & Specifications

Regular & High Alloy Split Helical Spring Lockwashers Drawing

Regular & High Alloy Split Helical Spring Lock Washers (ASME B18.21.1-1999)

Nominal Washer Size

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A

B 

(T+t)
2 

W 

Inside Diameter (ID)

 Outside Diameter (OD)

Mean Section Thickness 

Section Width 
Max Min Max Min Min
#2 0.086 0.094 0.088 0.172 0.020 0.035
#3 0.099 0.107 0.101 0.195 0.025 0.040
#4 0.112 0.120 0.114 0.209 0.025 0.040
#5 0.125 0.133 0.127 0.236 0.031 0.047
#6 0.138 0.148 0.141 0.250 0.031 0.047
#8 0.164 0.174 0.167 0.293 0.040 0.055
#10 0.190 0.200 0.193 0.334 0.047 0.062
#12 0.216 0.227 0.220 0.377 0.056 0.070
1/4 0.250 0.260 0.252 0.487 0.062 0.109
5/16 0.312 0.322 0.314 0.583 0.078 0.125
3/8 0.375 0.385 0.377 0.680 0.094 0.141
7/16 0.438 0.450 0.440 0.776 0.109 0.156
1/2 0.500 0.512 0.502 0.869 0.125 0.171
9/16 0.562 0.574 0.564 0.965 0.141 0.188
5/8 0.625 0.641 0.628 1.073 0.156 0.203
3/4 0.750 0.766 0.753 1.265 0.188 0.234
7/8 0.875 0.894 0.878 1.459 0.219 0.266
1 1.000 1.024 1.003 1.656 0.250 0.297
1-1/8 1.125 1.153 1.129 1.847 0.281 0.328
1-1/4 1.250 1.280 1.254 2.036 0.312 0.359
1-3/8  1.375 1.408 1.379 2.219 0.344 0.391
1-1/2 1.500 1.534 1.504 2.419  0.375 0.422 
1-3/4 1.750 1.789 1.758 2.679  0.389 0.424 
2 2.000 2.039 2.008 2.936  0.422 0.427 

 


Description


Regular: A coiled, hard, split circular washer with a slight trapezoidal wire section.
High-Alloy: Dimensionally the same to a regular split lock washer but manufactured from 4037 alloy steel
(sizes over 1" are the same to heavy split lock washers in size and material).
Stainless: A split lock made of austenitic stainless steel.

 

Applications/
Advantages


Regular: (A) Apply higher bolt tension per unit of added torque; (B) Provides a hard bearing surface, producing
more uniform torque control ; (C) Provides greater uniform load distribution ; (D) Resist's vibration and corrosion loosening ;
It's preferred when completed that the appearance is vital and the teeth under the head of the screw must be hidden;
(E) Lockwasher is preferred for use on hard bearing surfaces.
High Alloy: Designed for use with bolts and nuts from Grade-5 & Grade-8.
Stainless: For use in corrosive settings with stainless nuts and screws of a comparable stainless alloy.



Material


Carbon Steel: SAE J403 1055 - 1065 carbon steel.
High-Alloy Steel: 1/4 thru 1": SAE J404 4037 alloy steel;1-1/8 thru 1-1/2": SAE J403 1055 - 1065 carbon steel
18-8 Stainless: SAE J405 302 - 305 stainless steel.
316 Stainless: SAE J405 316 stainless steel.

Hardness


Carbon & High-Alloy Steel: Rockwell C38 - 46
Stainless: Thru 5/8": Rockwell C35 - 43; Sizes over 5/8": Rockwell C32 - 43

Twist Test


With the washer in a vice with the split ends free and directly above the vice jaws, a 90 Degree section of the free end is clutched
with a wrench and bent. Washers are to resist being twisted without indications of fracture through a 90 Degree angle.
When the washer ultimately breaks beyond the prescribed 90 Degree limit, a fine grain will be displayed in the structure at the
breaking point.
Plating


For details on carbon steel and alloy steel lock washer plating, see table above.