ASME B18.6.3 Slotted Undercut 82-deg Flat Countersunk Head Screw

ASME B18.6.3 Slotted Undercut 82-deg Flat Countersunk Head Machine Screws Standard is intended to cover the complete general and dimensional data for the various types of slotted and recessed head machine screws, tapping screws, and metallic drive screws recognized as American National Standard. Also included are appendices that provide specifications and instructions for the protrusion gaging of flat countersunk head screws; across-corners gaging of hex head screws; penetration gaging and wobble gaging of recessed head screws; approximate hole size for tapping screws; wrench openings for hex and square products; thread dimensions for the No. 0000, No. 000, and No. 00 sizes; means for determining effective grip lengths on screws; documentation for screw types and head types relegated to not-recommended or limited-usage status; and formulas on which dimensional data are based. It shall be understood, however, that where questions arise concerning acceptance of product, the dimensions in the tables shall govern over recalculation by formula.
The inclusion of dimensional data in ASME B18.6.3 Standard is not intended to imply that all of the products described are stock production sizes. Consumers should consult with suppliers concerning the availability of products.

ASME B18.6.3 Slotted Undercut 82-deg Flat Countersunk Head Screw Dimensions (mm)

Nominal Size or Basic Screw Diameter	Machine Screw Length, L	These Lengths or Shorter Are Undercut, L		Head Diameter, A		Head Height, H		Slot Width, J		Slot Depth, T		Protrusion Above Gaging Diameter, F		Gaging Diameter, G
		Type A & AB Tapping Screws	Other Types of Tapping Screws	Max.	Min.	Max.	Min.	Max.	Min.	Max.	Min.	Max.	Min.
0 - 0.0600	3.175	4.762	3.175	2.845	2.438	0.635	0.457	0.584	0.406	0.279	0.178	-	-	-
1 - 0.0730	3.175	4.762	3.969	3.480	3.048	0.787	0.584	0.660	0.483	0.356	0.229	-	-	-
2 - 0.0860	3.175	4.762	4.762	4.115	3.658	0.914	0.711	0.787	0.584	0.406	0.279	0.737	0.432	3.150
3 - 0.0990	3.175	5.556	5.556	4.750	4.242	1.067	0.838	0.889	0.686	0.483	0.305	0.787	0.457	3.759
4 - 0.1120	4.762	6.350	6.350	5.385	4.851	1.194	0.965	0.991	0.787	0.559	0.356	0.813	0.483	4.369
5 - 0.1250	4.762	6.350	6.350	6.020	5.461	1.346	1.092	1.092	0.889	0.610	0.406	0.864	0.508	4.978
6 - 0.1380	4.762	7.938	7.938	6.655	6.045	1.499	1.219	1.219	0.991	0.686	0.432	0.914	0.533	5.588
8 - 0.1640	6.350	11.112	11.112	7.925	7.239	1.778	1.473	1.372	1.143	0.813	0.533	0.991	0.584	6.782
10 - 0.1900	7.938	12.700	12.700	9.195	8.458	2.057	1.727	1.524	1.270	0.940	0.610	1.067	0.635	7.950
1/4 - 0.2500	11.112	15.875	15.875	12.116	11.227	2.718	2.337	1.905	1.626	1.270	0.813	1.270	0.737	10.770
5/16 - 0.3125	12.700	20.638	15.875	15.164	14.122	3.404	2.946	2.134	1.829	1.575	1.041	1.448	0.864	13.691
3/8 - 0.3750	14.288	...	15.875	18.212	17.018	4.089	3.556	2.388	2.057	1.905	1.245	1.651	0.991	16.586

ASME B18.6.3 Slotted Undercut 82-deg Flat Countersunk Head Screw Dimensions (Inch)

Nominal Size or Basic Screw Diameter	Machine Screw Length, L	These Lengths or Shorter Are Undercut, L		Head Diameter, A		Head Height, H		Slot Width, J		Slot Depth, T		Protrusion Above Gaging Diameter, F		Gaging Diameter, G
		Type A & AB Tapping Screws	Other Types of Tapping Screws	Max.	Min.	Max.	Min.	Max.	Min.	Max.	Min.	Max.	Min.
0 - 0.0600	1/8	3/16	1/8	0.112	0.096	0.025	0.018	0.023	0.016	0.011	0.007	-	-	-
1 - 0.0730	1/8	3/16	5/32	0.137	0.120	0.031	0.023	0.026	0.019	0.014	0.009	-	-	-
2 - 0.0860	1/8	3/16	3/16	0.162	0.144	0.036	0.028	0.031	0.023	0.016	0.011	0.029	0.017	0.124
3 - 0.0990	1/8	7/32	7/32	0.187	0.167	0.042	0.033	0.035	0.027	0.019	0.012	0.031	0.018	0.148
4 - 0.1120	3/16	1/4	1/4	0.212	0.191	0.047	0.038	0.039	0.031	0.022	0.014	0.032	0.019	0.172
5 - 0.1250	3/16	1/4	1/4	0.237	0.215	0.053	0.043	0.043	0.035	0.024	0.016	0.034	0.020	0.196
6 - 0.1380	3/16	5/16	5/16	0.262	0.238	0.059	0.048	0.048	0.039	0.027	0.017	0.036	0.021	0.220
8 - 0.1640	1/4	7/16	7/16	0.312	0.285	0.070	0.058	0.054	0.045	0.032	0.021	0.039	0.023	0.267
10 - 0.1900	5/16	1/2	1/2	0.362	0.333	0.081	0.068	0.060	0.050	0.037	0.024	0.042	0.025	0.313
1/4 - 0.2500	7/16	5/8	5/8	0.477	0.442	0.107	0.092	0.075	0.064	0.050	0.032	0.050	0.029	0.424
5/16 - 0.3125	1/2	13/16	5/8	0.597	0.556	0.134	0.116	0.084	0.072	0.062	0.041	0.057	0.034	0.539
3/8 - 0.3750	9/16	...	5/8	0.717	0.670	0.161	0.140	0.094	0.081	0.075	0.049	0.065	0.039	0.653