Metric Bolt Conversion

Metric bolt conversion data for industrial bolts/rods, machine screws and small diameter fasteners from Elgin Fastener Group includes metric to standard bolt conversions. The chart below shows metric bolt conversions and DIN numbers for fasteners.

Fastener ConversionApproximate Equivalency | Common DIN Numbers

 

Diameter/Decimal/Metric Chart for Small Diameter Fasteners

Gauge
or Diameter
Decimal (in) mm Metric fastener conversions for small diameter fasteners, industrial bolts and machine screws
No.0000 0.021 .53
No.000 0.034 .86
No.00 0.047 1.19
No.0 0.060 1.524
No.1 0.073 1.854
No.2 0.086 2.184
No.3 0.099 2.515
No.4 0.112 2.845
No.5 0.125 3.175
No.6 0.138 3.505
No.8 0.164 4.166
No.10 0.190 4.826
No.12 0.216 5.484

Fastener Conversion Chart

Inch Equivalent Metric Size-PitchISO and IFI Rec.
UNC UNF
1- 64 1- 72 M2x 0.4
3- 48 3- 56 M2.5x 0.45
4- 40 4- 48 M3x .5
6- 32 6- 40 M3.5x .6
8- 32 8- 36 M4x .7
10- 24 10- 32 M5x .8
1/4- 20 1/4- 28 M6x 1
5/16-18 5/16- 24 M8x 1.25
3/8-16 3/8- 24 M10x 1.5
7/16-14 7/16- 20 M12x 1.75
1/2- 13 1/2- 20 M14x 2
5/8- 11 5/8- 18 M18x 2
3/4- 10 3/4- 16 M20x 2.5
1- 8 1-12 M24x 3
1-1/4- 7 1-1/8- 12 M30x 3.5
1-1/2- 6 1-1/4- 12 M36x 4

Approximate Equivalency Chart Metric/US Roughly Equivalent US Bolt Materials

Metric Nut Class SAE J429Normally Used Grades ASTM Grades
4.6 4or 5 1 A307,Grade A
4.8 4or 5 2 .
5.8 5 2 .
8.8 8 5 A325,A449
9.8 9 5+ A193,B7 and B16
10.9 10or 12 8 A490,A354, Grade 8D
12.9 10or 12 . A540;B21 through B24

Common DIN Numbers for Metric Fasteners

DIN Hex Capscrews
931 Coarse thread pitch partially threaded (specify grade)
933 Coarse thread pitch fully threaded (specify grade)
930 Fine thread pitch partially threaded (specify grade)
961 Fine thread pitch fully threaded (specify grade)
DIN Nuts
934 Hex nuts (specify pitch and class)
985 Nylon insert locknuts (specify pitch and class)
980V All metal locknuts (specify pitch and class)
DIN Washers
125 Flatwashers
127 Lockwashers
DIN Socket Products
912 Socket head capscrews (normally GR 12.9 and coarse thread)
7991 Flat head socket capscrews (normally GR 12.9 and coarse thread)
916 Socket setscrews (normally GR 12.9 and coarse thread)
DIN Machine Screws
7985 Pan head Phillips drive zinc plated
965 Flat head Phillips drive zinc plated
DIN Threaded Rod
975 All threaded rod (normally 1 meter lengths, specify grade and pitch)