Sheet metal screw pilot holes: drill size and hole diameter for Types AB, A and 1/23/F, by sheet thickness (#2 to 1/2) — dimension sheet Source: Xem Studio, https://xemstudio.com/objects/sheet-metal-screw-pilot-holes/ (sheet CC BY 4.0) Basis: AFT Fasteners' self-tapping screw hole-size tables (test-plate gage and thickness, drill, hole diameter) and Engineers Edge's Type A table by metal thickness (pierced / extruded versus drilled / clean punched); numbers only Catalog version: 2026-10-20 Sizes: see table below - Inch tables. AFT gives, per screw size and thread (size-TPI), the test-plate gage and its thickness max / min, the drill size (number, letter, fraction or mm as printed) and the resulting hole diameter, for Types AB / B / 25 (thread forming), Type A (spaced thread, no plate thickness given) and Types 1 / 23 / F (thread cutting). Engineers Edge gives Type A holes by metal thickness: the hole diameter for pierced or extruded holes and for drilled or clean-punched holes, with the drill size, for #4 to #14 in steel, stainless steel, Monel, brass and aluminum. AFT states holes can be drilled, core drilled, punched, pierced or extruded and that burrs should be removed if they interfere; hole size is the nominal hole diameter, not a tolerance. Engineers Edge prints no units; the values read as inches. - Oddities kept as printed, not corrected: AFT's Types AB row '4.24' (printed with a dot; the thread is 4-24); the 8-18 row gives gage 14 with thickness .1270 / .1230 in (1/8 in), unlike the gage 14 rows above it (.0770 / .0730 in); the 3-48 row of the thread-cutting table prints .0920 for both max and min. AFT's Type A table lists sizes 5 to 24 (24-9 for the 11/32 in drill) with threads different from the AB table (for example 6-18 versus 6-20), because the type has a different thread. - Not on this page: pilot holes for plastics and wood (see plastic-thread-forming-screw-holes and wood-screws-flat-head-inch), the AFT Type U drive-screw and High-Low tables (read but not tabulated), and metric ST sizes (the sources read give no hole table for them). The two sources do not overlap in the same screw type and thickness for every size: for example #8 Type A is 0.136 in (drill #29) in AFT's Type A table, Engineers Edge prints 0.125 in (1/8 in drill) for drilled holes in 0.018 to 0.036 in steel and 0.136 in for pierced holes, so check the table for your thickness. - No file: these are hole sizes (numbers). McMaster-Carr sells sheet metal screws with per-part STEP; its category is linked on self-tapping-screws-iso-7049-pan-head. source / screw type size (size-TPI, or # for Engineers Edge) test plate or metal thickness drill size hole diameter, drilled / clean punched (in) hole diameter, pierced or extruded (in) AFT, Types AB / B / 25 2-32 gage 18, .0500 / .0460 in 48 .0760 — AFT, Types AB / B / 25 3-28 gage 18, .0500 / .0460 in 46 .0810 — AFT, Types AB / B / 25 4-24 (printed 4.24) gage 18, .0500 / .0460 in 44 .0860 — AFT, Types AB / B / 25 5-20 gage 18, .0500 / .0460 in 36 .1065 — AFT, Types AB / B / 25 6-20 gage 14, .0770 / .0730 in 32 .1160 — AFT, Types AB / B / 25 7-19 gage 14, .0770 / .0730 in 30 .1285 — AFT, Types AB / B / 25 8-18 gage 14, .1270 / .1230 in 29 .1360 — AFT, Types AB / B / 25 10-16 gage 1/8, .1270 / .1230 in 21 .1590 — AFT, Types AB / B / 25 12-14 gage 1/8, .1270 / .1230 in 3/16 .1875 — AFT, Types AB / B / 25 1/4-14 gage 3/16, .1905 / .1845 in 5.5 mm .2165 — AFT, Types AB / B / 25 5/16-12 gage 3/16, .1905 / .1845 in I .2720 — AFT, Types AB / B / 25 3/8-12 gage 3/16, .1905 / .1845 in 21/64 .3281 — AFT, Type A 5-20 — #36 0.1065 — AFT, Type A 6-18 — #32 0.1160 — AFT, Type A 7-16 — #30 0.1285 — AFT, Type A 8-15 — #29 0.1360 — AFT, Type A 9-14 — #26 0.1470 — AFT, Type A 10-12 — #21 0.1590 — AFT, Type A 12-11 — 3/16 0.1875 — AFT, Type A 14-10 — 5.5 mm 0.2165 — AFT, Type A 20-9 — L 0.2900 — AFT, Type A 24-9 — 11/32 0.3438 — AFT, Types 1 / 23 / F (thread cutting) 2-56 gage 18, .0800 / .0760 in 49 0.0730 — AFT, Types 1 / 23 / F (thread cutting) 3-48 gage 18, .0920 / .0920 in 46 0.0810 — AFT, Types 1 / 23 / F (thread cutting) 4-40 gage 18, .1110 / .1070 in 41 0.0960 — AFT, Types 1 / 23 / F (thread cutting) 5-40 gage 18, .1110 / .1070 in 37 0.1010 — AFT, Types 1 / 23 / F (thread cutting) 6-32 gage 14, .1425 / .1385 in 31 0.1200 — AFT, Types 1 / 23 / F (thread cutting) 8-32 gage 14, .1905 / .1845 in 26 0.1470 — AFT, Types 1 / 23 / F (thread cutting) 10-24 gage 1/8, .1905 / .1845 in 17 0.1730 — AFT, Types 1 / 23 / F (thread cutting) 10-32 gage 1/8, .1905 / .1845 in 16 0.1770 — AFT, Types 1 / 23 / F (thread cutting) 12-24 gage 1/8, .1905 / .1845 in 8 0.1990 — AFT, Types 1 / 23 / F (thread cutting) 1/4-20 gage 3/16, .2530 / .2470 in 1 0.2280 — AFT, Types 1 / 23 / F (thread cutting) 5/16-18 gage 3/16, .3155 / .3095 in L 0.2900 — AFT, Types 1 / 23 / F (thread cutting) 3/8-16 gage 3/16, .3780 / .3720 in T 0.3580 — AFT, Types 1 / 23 / F (thread cutting) 1/2-13 gage 3/16, .471 / .443 in 29/64 0.4531 — Engineers Edge, Type A by metal thickness #4 0.015 in 44 0.086 — Engineers Edge, Type A by metal thickness #4 0.018 in 44 0.086 — Engineers Edge, Type A by metal thickness #4 0.024 in 42 0.094 0.098 Engineers Edge, Type A by metal thickness #4 0.030 in 42 0.094 0.098 Engineers Edge, Type A by metal thickness #4 0.036 in 40 0.098 0.098 Engineers Edge, Type A by metal thickness #6 0.015 in 37 0.104 — Engineers Edge, Type A by metal thickness #6 0.018 in 37 0.104 — Engineers Edge, Type A by metal thickness #6 0.024 in 37 0.104 0.111 Engineers Edge, Type A by metal thickness #6 0.030 in 37 0.104 0.111 Engineers Edge, Type A by metal thickness #6 0.036 in 36 0.106 0.111 Engineers Edge, Type A by metal thickness #7 0.015 in 32 0.116 — Engineers Edge, Type A by metal thickness #7 0.018 in 32 0.116 — Engineers Edge, Type A by metal thickness #7 0.024 in 32 0.116 0.120 Engineers Edge, Type A by metal thickness #7 0.030 in 32 0.116 0.120 Engineers Edge, Type A by metal thickness #7 0.036 in 32 0.116 0.120 Engineers Edge, Type A by metal thickness #7 0.048 in 31 0.120 0.120 Engineers Edge, Type A by metal thickness #8 0.018 in 1/8 0.125 — Engineers Edge, Type A by metal thickness #8 0.024 in 1/8 0.125 0.136 Engineers Edge, Type A by metal thickness #8 0.030 in 1/8 0.125 0.136 Engineers Edge, Type A by metal thickness #8 0.036 in 1/8 0.125 0.136 Engineers Edge, Type A by metal thickness #8 0.048 in 30 0.128 0.136 Engineers Edge, Type A by metal thickness #10 0.018 in 29 0.136 — Engineers Edge, Type A by metal thickness #10 0.024 in 29 0.136 0.157 Engineers Edge, Type A by metal thickness #10 0.030 in 29 0.136 0.157 Engineers Edge, Type A by metal thickness #10 0.036 in 29 0.136 0.157 Engineers Edge, Type A by metal thickness #10 0.048 in 25 0.149 0.157 Engineers Edge, Type A by metal thickness #12 0.024 in 20 0.161 — Engineers Edge, Type A by metal thickness #12 0.030 in 20 0.161 0.185 Engineers Edge, Type A by metal thickness #12 0.036 in 20 0.161 0.185 Engineers Edge, Type A by metal thickness #12 0.048 in 20 0.161 0.185 Engineers Edge, Type A by metal thickness #14 0.024 in 13 0.185 — Engineers Edge, Type A by metal thickness #14 0.030 in 12 0.189 0.209 Engineers Edge, Type A by metal thickness #14 0.036 in 11 0.191 0.209 Engineers Edge, Type A by metal thickness #14 0.048 in 9 0.196 0.209 Files elsewhere (not hosted by Xem Studio; license as stated by the publisher): - AFT Fasteners: Self-tapping screws hole size data, Types AB / B / 25, A, 1 / 23 / F, U and High-Low: test-plate gauge and thickness, drill size, hole diameter — web — Publisher's page; dimensions are facts — https://www.aftfasteners.com/self-tapping-screws-hole-size-data-for-types-a-ab-b-25-1-23-f-u-high-low-technical-information - Engineers Edge: Pilot hole sizes for Type A steel sheet metal screws by metal thickness: pierced or extruded versus drilled or clean punched, drill size, #4 to #14 — web — Publisher's page; dimensions are facts — https://engineersedge.com/hardware/pilot_hole_sizes_for_steel_sheet_metal_15670.htm No true-size file yet: the published figures do not fix the whole shape; a measured scan is planned. API: https://xemstudio.com/api/geometry?object=sheet-metal-screw-pilot-holes