Countersunk External Tooth Lock Washers: Dimensions & Specifications

Countersunk External Tooth Lockwashers Drawing

Countersunk External Tooth Lock Washers (ASME B18.21.1-2009)


 
Nominal Washer Size

A

B

C

D 

 Inside Diameter (ID)

 Outside Diameter (OD)

Thickness (TH)

Length 
Max Min Approx. Max Min Max Min
2** 0.086 0.095 0.089 0.180 - 0.013 - - 
 
4 0.112 0.123 0.113 0.213 0.019 0.015 0.065 0.050 
6 0.138 0.150 0.140 0.289 0.021 0.017 0.092 0.082 
8 0.164 0.177 0.167 0.322 0.021 0.017 0.099 0.083 
10 0.190 0.205 0.195 0.354 0.025 0.020 0.105 0.088
12 0.216 0.231 0.220 0.421 0.025 0.020 0.128 0.118
1/4 0.250 0.267 0.255 0.454 0.025 0.020 0.128 0.113
5/16 0.3125 0.333 0.318 0.599 0.028 0.023 0.192 0.165
3/8 0.375 0.398 0.383 0.765 0.034 0.028 0.255 0.242
1/2 0.500 0.529 0.512 0.976 0.045 0.037 0.304 0.294

 

**ITW Shakeproof specification, not ASME B18.21.1


Description


A conical shaped bearing surface with an external tooth lock washer.

Applications/
Advantages


Intended for use with flat or oval head screws with countersunk angles of 82° or 100°.


Material

Steel: SAE 1050 - 1065 spring steel.
18-8 Stainless: SAE 301 - 305 stainless steel.
Hardness

Steel: Rockwell C40 - 50
18-8 Stainless: Annealed 88 minimum Rockwell B, 1/4 hard through full hard Rockwell C20 - 45
Plating

See more information above on the plating of steel lock washers.