Flat-head wood screws, inch #4–#14 (ASME B18.6.1): body and head diameter, pilot and clearance holes from three sources + envelope models — dimension sheet Source: Xem Studio, https://xemstudio.com/objects/wood-screws-flat-head-inch/ (sheet CC BY 4.0) Basis: AFT Fasteners and Engineers Edge for the B18.6.1 body and flat-head dimensions (they agree), three pilot-hole sources (Albany County Fasteners, Fine Power Tools, Engineers Edge) that disagree and are shown side by side; six envelope models as files Catalog version: 2026-10-20 Overall (mm): length 38.1, width 12.9, height 12.9 - Dimensions are inches, flat (countersunk) head slotted wood screws as printed on the B18.6.1 tables: threads per inch; nominal body diameter (Engineers Edge, = 0.060 + 0.013 × the screw number) with AFT's body max / min (Engineers Edge's note gives the tolerance as +0.004 / −0.007 for cut threads); flat head diameter A max / min and head height H (ref). The two tables agree on A, H and body diameter for every size #4 to #14; the mm column is the nominal body diameter converted, computed (× 25.4). AFT's table also prints a second diameter pair per size (smaller by about 0.02 in, not labelled clearly in the text read); it is not shown. - Pilot and clearance holes are not part of the B18.6.1 table, and the three sources disagree, so all are shown. Albany County Fasteners: softwood / hardwood pilot and clearance for #4–#14. Fine Power Tools: its first table; the page also carries a second, extended table with other values (it gives 1/16 for #4 softwood and 1/8 for #8 hardwood) that is not used. Engineers Edge: hardwood / softwood pilot only, listed there as per B18.6.1. Examples of the spread: #4 softwood pilot 5/64 (Albany) against 3/64 (Fine Power Tools and Engineers Edge); #8 softwood 7/64 against 5/64; #10 hardwood 9/64 (Albany, Fine Power Tools) against 7/64 (Engineers Edge). Clearance holes agree between Albany and Fine Power Tools for #6 to #14 (9/64, 11/64, 3/16, 7/32, 1/4) and differ for #4 (1/8 against 7/64). Pilot sizes depend on the wood and screw design: use the maker's chart for your screw. - Files are Xem-drawn envelopes, not the real screw: the flat head is a cone from the head diameter A max (top) down to the nominal body diameter over H ref (the cone angle follows from those numbers); the body is a plain cylinder at the nominal diameter (the real thread is smaller at the root); no slot or recess, no gimlet point. The overall length 1-1/2 in (38.1 mm) is an example chosen by Xem for all six files, not a published length. The head top is flat. - Not on this page: round, oval, pan and other heads (B18.6.1 covers them), slot and recess dimensions, thread length. Metric chipboard / wood screws 3–6 mm: no table could be verified (McMaster's metric wood-screw listings are hex-head thread-forming M6 to M16 and are lag-type screws, not this size range), so none is shown. McMaster-Carr sells wood screws with per-part STEP; its category is linked, not copied. Hex lag screws: lag-screws-hex-inch. screw # TPI nominal body dia (in) nominal body dia (mm, computed) body dia max / min (AFT, in) flat head dia A max / min (in) head height H ref (in) pilot softwood / hardwood (Albany, in) clearance (Albany, in) pilot softwood / hardwood (Fine Power Tools, in) clearance (Fine Power Tools, in) pilot hardwood / softwood (Engineers Edge, in) #4 22 .112 2.84 .116 / .105 .225 / .195 .067 5/64 / 3/32 1/8 3/64 / 5/64 7/64 1/16 / 3/64 #5 20 .125 3.17 .129 / .118 .252 / .220 .075 5/64 / 3/32 9/64 — — — #6 18 .138 3.51 .142 / .131 .279 / .244 .083 3/32 / 7/64 9/64 1/16 / 3/32 9/64 5/64 / 1/16 #7 16 .151 3.84 .155 / .144 .305 / .268 .091 3/32 / 7/64 5/32 — — — #8 15 .164 4.17 .168 / .157 .332 / .292 .100 7/64 / 1/8 11/64 5/64 / 7/64 11/64 3/32 / 5/64 #9 14 .177 4.50 .181 / .170 .358 / .316 .108 7/64 / 1/8 3/16 — — — #10 13 .190 4.83 .194 / .183 .385 / .340 .116 1/8 / 9/64 3/16 3/32 / 9/64 3/16 7/64 / 3/32 #12 11 .216 5.49 .220 / .209 .438 / .389 .132 9/64 / 5/32 7/32 7/64 / 5/32 7/32 1/8 / 7/64 #14 10 .242 6.15 .246 / .235 .507 / .452 .153 5/32 / 3/16 1/4 5/32 / 11/64 1/4 9/64 / 1/8 Files elsewhere (not hosted by Xem Studio; license as stated by the publisher): - AFT Fasteners: Wood screws dimensions and mechanical specs (ASME B18.6.1): nominal size, threads per inch, body diameter max / min, flat head diameter A, head height H — web — Publisher's page; dimensions are facts — https://www.aftfasteners.com/wood-screws-dimensions-mechanical-specs/ - Engineers Edge: ANSI B18.6.1 wood screw dimensions: threads per inch, body diameter, flat head diameter A max / min, head height H — web — Publisher's page; dimensions are facts — https://ns2.engineersedge.com/hardware/ansi_wood_screws_per_ansi_b1861__14855.htm - Albany County Fasteners: Wood screw pilot hole guide: softwood pilot, hardwood pilot, clearance hole by screw size #2 to 5/16 — web — Distributor guide; numbers only — https://www.albanycountyfasteners.com/media/51/31/8c/1764682594/wood-screw-pilot-hole-guide.pdf - Fine Power Tools: What size drill bit for a screw: softwood pilot, hardwood pilot, shank clearance hole #4 to #14 — web — Tool-review page; numbers only (its second table has other values) — https://www.finepowertools.com/woodworking/what-size-drill-bit-for-screw/ - Engineers Edge: Pilot hole drill sizes for wood screws, hardwood and softwood, #2 to #14 (page says per ANSI B18.6.1) — web — Publisher's page; dimensions are facts — https://engineersedge.com/hardware/pilot_hole_drill_sizes_wood_screws_14857.htm - McMaster-Carr: Wood screws (free STEP/IGES per part, for your own design use; no redistribution) — STEP, IGES, PDF — McMaster-Carr site terms: personal design use, no redistribution [verify license at link] — https://www.mcmaster.com/wood-screws Free files (CC BY 4.0, Xem Studio; STEP + STL, 6 parts): https://xemstudio.com/files/hardware/wood-screws-flat-head-inch/index.json API: https://xemstudio.com/api/geometry?object=wood-screws-flat-head-inch