Machinery's Handbook, 31st Edition
WING NUTS, WING SCREWS AND THUMB SCREWS
1933
sizes No. 4 through 1 ∕ 4 inch and for nominal lengths of 0.25 to 0.75 inch, 0.12-inch incre ments; from 0.75- to 1.50-inch lengths, 0.25-inch increments; and for 1.50- to 3.00-inch lengths, 0.50-inch increments. For sizes 5 ∕ 16 through 1 ∕ 2 inch and for 0.50- to 1.50-inch lengths, 0.25-inch increments; for 1.50- to 3.00-inch lengths, 0.50-inch increments; and for 3.00- to 4.00-inch lengths, 1.00-inch increments. Threads for Wing Screws and Thumb Screws.— Threads for all types of wing screws and thumb screws are in conformance with ANSI Standard Unified Thread, Class 2A. For threads with an additive finish the Class 2A maximum diameters apply to an unplated screw or to a screw before plating, whereas the basic diameters (Class 2A maximum diam eters plus the allowance) apply to a screw after plating. All types of wing and thumb screws should have complete (full form) threads extending as close to the head or shoulder as practicable. Points for Wing and Thumb Screws.— Wing and thumb screws are normally supplied with plain points (sheared ends). Where so specified, these screws may be obtained with cone, cup, dog, flat or oval points as shown in Table 8. Table 8. American National Standard Alternate Points for Wing and Thumb Screws ANSI/ASME B18.17-1968 (Withdrawn)
Slight flat permissible
80°– 90°
( see note 1 )
90° ± 2° ( see note 1 )
O 118° ± 5°
R OVAL POINT
CUP POINT
CONE POINT
Slight fillet permissible
+ 5° – 0°
35°
Q
( see note 1 )
80°–90° ( see note 1 )
P
Slight radius or chamfer permissible
O FLAT POINT
DOG POINT
O
P
Q
R
Nominal Size or Basic Screw Diamter a 4 (0.1120) 6 (0.1380) 8 (0.1640) 10 (0.1900) 12 (0.2160) 1 ∕ 4 (0.2500) 5 ∕ 16 (0.3125) 3 ∕ 8 (0.3750) 7 ∕ 16 (0.4375) 1 ∕ 2 (0.5000) 5 ∕ 8 (0.6250)
Dog Point b
Oval Point Radius
Cup and Flat Point Diameter
Diameter
Length
Max. 0.061 0.074 0.087 0.102 0.115 0.132 0.172 0.212 0.252 0.291 0.371
Min. 0.051 0.064 0.076 0.088 0.101 0.118 0.156 0.194 0.232 0.270 0.347
Max. 0.075 0.092 0.109 0.127 0.144 0.156 0.203 0.250 0.297 0.344 0.469
Min. 0.070 0.087 0.103 0.120 0.137 0.149 0.195 0.241 0.287 0.334 0.456
Max. 0.061 0.075 0.085 0.095 0.115 0.130 0.161 0.193 0.224 0.255 0.321
Min. 0.051 0.065 0.075 0.085 0.105 0.120 0.151 0.183 0.214 0.245 0.305
Max. 0.099 0.140 0.156 0.172 0.188 0.219 0.256 0.312 0.359 0.406 0.500
Min. 0.084 0.109 0.125 0.141 0.156 0.188 0.234 0.281 0.328 0.375
0.469 a Where specifying nominal size in decimals, zeros in the fourth decimal place are omitted. b The axis of dog points shall not be eccentric with the axis of the screw by more than 3 percent of the basic screw diameter or 0.005 in., whichever is the smaller. All dimensions in inches. 1 The external point angles specified shall apply to those portions of the angles which lie below the thread root diameter, it being recognized the angle within the thread profile may be varied due to the manufacturing processes.
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