Common bolt & screw shapes

Standard Note Equivalent standards Image
ISO 4014 Hex bolts with shank / partial thread DIN 931 DIN
ISO 4017 Hex bolts with full thread (up to the head) DIN 933
ISO 4762 Cylindrical hex-socket head, partial thread DIN 912 DIN
DIN 6912 Like DIN 912 / ISO 4762 but with a thinner head
GB 2672 Torx ‘pan head’ screws. Popular in China in small sizes and A2 stainless steel GB
ISO 10642 Countersunk hex-socket head DIN 7991 ISO
DIN 571 Hex head wood screw
ISO 7050 C Countersunk cross-head tapping screw, sharp point DIN 7982 C
ISO 7050 F Countersunk cross-head tapping screw, blunt point DIN 7982 F


  • A -TX suffix to the standard for hex-socket head bolts (eg. DIN912-TX) indicates Torx (ISO 10664) is used instead of the standard hex socket.
  • Likewise, the -H and -Z suffixes indicate the type of cross drive, H for Phillips, Z for Pozidriv.

For a more complete overview of screw drive shapes please see:

Common nut shapes

Standard Note Equivalent standards Image
ISO 4032 The ‘garden variety’ nuts DIN 934
ISO 4035 Thinner version of the standard nuts DIN 439
ISO 10511 Most common ‘nyloc’ type of locknut DIN 985
ISO 2982 Lock nuts commonly used for bearings (see below), axles or, spindles DIN 981, CSN 023630 {img}
DIN 557 Square nut
DIN 562 Thin square nut

Metric threads (ISO 724)

A short list of standard thread sizes. All sizes are in mm unless otherwise specified.

For common nuts & bolts

Below table shows common metric thread sizes with coarse pitch, matching most nuts and/or bolts available on the market.

Size / Nominal Diameter Pitch
M1.6 0.35
M2 0.40
M2.5 0.45
M3 0.50
M4 0.70
M5 0.80
M6 1.00
M8 1.25
M10 1.50
M12 1.75
M16 2.00
M20 2.50

For DIN 981 / ISO 2982 / KM-type lock nuts

Below table shows standard metric fine thread sizes for KM type lock nuts.

Nominal Diameter Pitch Size
M10 0.75 KM0
M12 1.00 KM1
M15 1.00 KM2
M17 1.00 KM3
M20 1.00 KM4
M24 1.50 KM5
M30 1.50 KM6
M35 1.50 KM7
M40 1.50 KM8
M45 1.50 KM9
M50 1.50 KM10
M55 2.00 KM11
M60 2.00 KM12
M65 2.00 KM13
M70 2.00 KM14
M75 2.00 KM15
M80 2.00 KM16
M85 2.00 KM17
M90 2.00 KM18
M95 2.00 KM19
M100 2.00 KM20
M105 2.00 KM21
M110 2.00 KM22
M115 2.00 KM23

Locknuts vs serrated washers

To summarize this in one short and memorable phrase:

Do not use serrated lock washers. Use nyloc nuts (nuts with a nylon retaining insert) with a normal washer.

The below video illustrates this better than any words could:

Note that neither serrated washers nor nyloc nuts should be re-used, but in general practice nyloc nuts also fare better after re-use.