Library › Hardware › Fasteners ·

Hex head screws, M3–M8 (ISO 4017)

What size hex pocket holds an M5 hex head bolt so it can't turn? · Hardware · basis: ISO 4017 (fully threaded hex head screws): width across flats s and head height k

Exact dimensions. Every file is drawn at true size with no printing tolerance. The holes and pins that meet another part are listed below under Mating features, with the fit each joint needs; open those by your printer's or process's clearance before making the part. Mating features

sizes
5 in table

Notes

  • Hex head: s across flats, k high, corners s × 1.155. A pocket that keeps the head from turning is drawn at s × k exactly (see Mating features), so a nut can be run down from the other side with one tool.
  • Used in the two-bolt tri-clamp clamps: M5 × 30 in the 1½–4 in clamp halves, M8 in the 10 and 12 in clamps; each clamp half has the head pocket on one lug and a plain hole on the other.

Sizes

threadwidth_af_mmcorner_mmhead_height_mmlengths_mm
M35.56.42.010, 16, 20
M47.08.12.812, 16, 20, 25
M58.09.23.516, 20, 25, 30, 40
M610.011.54.020, 25, 30, 40
M813.015.05.320, 25, 30, 40, 50

Mating features

Drawn at the exact size. Open press, slide, run and socket features by your process's clearance; leave designed gaps and clamp fits as drawn.

featureexactmates withfitfiles
hex heads × k (M5 8 × 3.5, M8 13 × 5.3; ISO 4017)hex pocket in a clamp lugsockethexbolt-*
shankthread major (M5 Ø5)clearance hole (ISO 273) and nutdesignedhexbolt-*

Where the files are

Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.

McMaster-CarrHex head screws (free STEP/IGES/STL per part, for your own design use; no redistribution)STEP, IGES, STL, PDFMcMaster-Carr site terms: personal design use, no redistribution verify
WikipediaScrewwebCC BY-SA 4.0 (text)

Free files

★ Free files 21 parts. Generated by Xem Studio from the standard; threads are plain cylinders at major diameter. CC BY 4.0. index.json

hexbolt-m3x10ISO 4017 M3 × 10 hex head, 5.5 AF × 2 head, thread as plain cylinderSTEP · STL
hexbolt-m3x16ISO 4017 M3 × 16 hex head, 5.5 AF × 2 head, thread as plain cylinderSTEP · STL
hexbolt-m3x20ISO 4017 M3 × 20 hex head, 5.5 AF × 2 head, thread as plain cylinderSTEP · STL
hexbolt-m4x12ISO 4017 M4 × 12 hex head, 7 AF × 2.8 head, thread as plain cylinderSTEP · STL
hexbolt-m4x16ISO 4017 M4 × 16 hex head, 7 AF × 2.8 head, thread as plain cylinderSTEP · STL
hexbolt-m4x20ISO 4017 M4 × 20 hex head, 7 AF × 2.8 head, thread as plain cylinderSTEP · STL
hexbolt-m4x25ISO 4017 M4 × 25 hex head, 7 AF × 2.8 head, thread as plain cylinderSTEP · STL
hexbolt-m5x16ISO 4017 M5 × 16 hex head, 8 AF × 3.5 head, thread as plain cylinderSTEP · STL
hexbolt-m5x20ISO 4017 M5 × 20 hex head, 8 AF × 3.5 head, thread as plain cylinderSTEP · STL
hexbolt-m5x25ISO 4017 M5 × 25 hex head, 8 AF × 3.5 head, thread as plain cylinderSTEP · STL
hexbolt-m5x30ISO 4017 M5 × 30 hex head, 8 AF × 3.5 head, thread as plain cylinderSTEP · STL
hexbolt-m5x40ISO 4017 M5 × 40 hex head, 8 AF × 3.5 head, thread as plain cylinderSTEP · STL
hexbolt-m6x20ISO 4017 M6 × 20 hex head, 10 AF × 4 head, thread as plain cylinderSTEP · STL
hexbolt-m6x25ISO 4017 M6 × 25 hex head, 10 AF × 4 head, thread as plain cylinderSTEP · STL
hexbolt-m6x30ISO 4017 M6 × 30 hex head, 10 AF × 4 head, thread as plain cylinderSTEP · STL
hexbolt-m6x40ISO 4017 M6 × 40 hex head, 10 AF × 4 head, thread as plain cylinderSTEP · STL
hexbolt-m8x20ISO 4017 M8 × 20 hex head, 13 AF × 5.3 head, thread as plain cylinderSTEP · STL
hexbolt-m8x25ISO 4017 M8 × 25 hex head, 13 AF × 5.3 head, thread as plain cylinderSTEP · STL
hexbolt-m8x30ISO 4017 M8 × 30 hex head, 13 AF × 5.3 head, thread as plain cylinderSTEP · STL
hexbolt-m8x40ISO 4017 M8 × 40 hex head, 13 AF × 5.3 head, thread as plain cylinderSTEP · STL
hexbolt-m8x50ISO 4017 M8 × 50 hex head, 13 AF × 5.3 head, thread as plain cylinderSTEP · STL

Plain text: sheet.txt · JSON: /api/geometry?object=hex-head-screws-metric

Hex head screws, M3–M8 (ISO 4017), isometric render of a generated part
Render of hexbolt-m5x30 from the free STEP; not to scale.

How it fits

In these build lists

Gamma Stirling, 2 in tri-clampHot spool with a shell displacer, a crank head that carries the crankshaft, the …Thermoacoustic standing-wave engine, 2 in spoolsNo moving parts: a heated stack between two heat exchangers in a closed-open 2 i…Beta Stirling, rhombic drive, 2 in tri-clampDisplacer and piston in one bore, driven by two counter-rotating gears on a rhom…Free-piston Stirling, 2 in tri-clampNo crank: piston and displacer each hang on a stack of spiral flexures, with a t…Tri-clamp tee diaphragm gamma, 2 inA tea-light gamma in 2 in tri-clamp: displacer in a 3 in spool, a short-outlet t…Tri-clamp elbow diaphragm alpha, 2 inA torch-heated alpha in 2 in tri-clamp: a square of fittings with a diaphragm he…Tri-clamp cross diaphragm gamma, 2 inA fast gamma in 2 in tri-clamp: a hot cap and short spool over a torch, a cross …Tri-clamp sealed diaphragm generator, 2 inA sealed, pressurised gamma Stirling generator in 2 in tri-clamp: a plain closed…Thermoacoustic standing-wave engine,…A propane-fired standing-wave thermoacoustic engine in 2 in tri-clamp: a plain c…Tri-clamp rolling-diaphragm beta, 2 inA torch-heated beta in two pieces of pressure vessel: a 2 in × 150 cup with the …Tri-clamp rolling-diaphragm Ringbom, 2 inThe simplest mechanism I could draw: one crank, one con-rod, and a free displace…Tri-clamp rolling-diaphragm gamma, 2 inThe Ringbom's cup, tee and power head with the displacer on the crank: a pushrod…Thermoacoustic traveling-wave loop, 2 in tri-clampA looped traveling-wave thermoacoustic engine in 2 in tri-clamp, torch-heated, w…Thermoacoustic standing-wave engine, half-wave,…The propane standing-wave engine as a half-wave: closed at both ends, the top cl…HTD engine, 10 in tri-clamp…A big flat gamma Stirling for a propane burner: a Ø240 displacer in a 10 in weld…Linear alternator module, 2 in, open frame…The same linear alternator on an open frame: it clamps on the end of an unpressu…

You might also need

Questions

How big is an M5 hex head?

8 mm across flats, 3.5 mm high, 9.2 mm across corners (ISO 4017). A pocket that holds it is 8 AF × 3.5 deep.

How big is an M8 hex head?

13 mm across flats, 5.3 mm high, 15.0 mm across corners (ISO 4017).

Why put the bolt head in a hex pocket?

The pocket stops the bolt turning, so the nut on the other side can be tightened with one wrench.