ASME B 18.6.3 (H4C) - 2024 Oval 82-deg Countersunk Trim Head Screws (ASTM F837 / F468)

Unit:

Thread Size
d

4#
(3)

5#
(4)

6#
(4)

d	Nominal Size
PP
Code	Head Size
d_s	max
	min
d_k	max
	min
k	Ref
f	Ref.
R	Ref.
L₁	min
α	max
	min
Socket No.
M₁	short	Ref.
	Long	Ref.
M₂	short	Ref.
	Long	Ref.
P	short, Type I	max
		min
	Long, Type I	max
		min
	short, Type IA	max
		min
	Long, Type IA	max
		min

0.1120	0.1250	0.1380
40	40	32
3	4	4
0.112	0.125	0.138
0.106	0.119	0.131
0.187	0.212	0.212
0.167	0.191	0.191
0.057	0.066	0.058
0.033	0.037	0.037
0.014	0.017	0.017
0.062	0.062	0.062
82°	82°	82°
80°	80°	80°
1	1	1
0.118	0.130	0.130
0.118	0.130	0.130
0.118	0.130	0.130
0.118	0.130	0.130
0.074	0.087	0.087
0.057	0.070	0.070
0.074	0.087	0.087
0.057	0.070	0.070
0.074	0.086	0.086
0.058	0.070	0.070
0.074	0.086	0.086
0.058	0.070	0.070

①,Edge of head may be rounded or flat.
②,Short machine screws include nominal lengths up to and including 1 1/8 in. for sizes No.5 and smaller, and 2 in. for sizes No.6 and larger.
③,Machine Screw Length of Thread

1) Sizes No.5 and smaller.

Screws of nominal lengths equal to three diameters and shorter shall have full-form threads extending to within one pitch (thread) of the bearing surface of the head, or closer, if practicable. Nominal lengths greater than three diameters, up to and including 1-1/8 in., shall have full-form threads extending to within two pitches (threads) of the bearing surface of the head, or closer, if practicable. Screws of longer nominal lengths shall, unless otherwise specified, have a minimum length of full-form thread of 1 in.

2) Sizes No.6 and smaller.

Screws of nominal lengths equal to three diameters and shorter shall have full-form threads extending to within one pitch (thread) of the bearing surface of the head, or closer, if practicable. Nominal lengths greater than three diameters, up to and including 2 in., shall have full-form threads extending to within two pitches (threads) of the bearing surface of the head, or closer, if practicable. Screws of longer nominal lengths shall have a minimum length of full-form thread of 1.5 in. unless otherwise specified.