What is the difference between metric and standard fasteners?
Depending on the context, “standard” often refers to U.S. fasteners. This typically means we’re talking about measuring units in inches, whereas metric is exactly that: measurements based on metric units, such as millimetres. Keep in mind, however, the U.S. is now producing fasteners using the metric system.
The other definition of standard is the set of specifications as defined by organisations, which we’ll talk about below, and this article will also cover:
Metric vs standard
The major difference between metric and standard is in how threads are specified. Standard fasteners are either Unified National Coarse Thread (UNC) or Unified National Fine Thread (UNT). Standard metric threads, meaning ISO metric threads in this case, are not specified this way, though they are comparable to UNC threads.
Standard metric screw threads are designated by pitch in millimetres (mm). This is the distance measured between the peaks of two adjacent threads. ASTM fastener standards measure threads by TPI: threads per inch. You literally just count the number of threads that cover a one-inch distance.
Metric screw sizes vs standard
Metric and standard sizes are communicated differently. Standard metric screw dimensions are determined by the pitch and the major diameter, which as the illustration shows, is the largest diameter of the screw.
Let’s say it’s 4mm, in which case it appears as M4 (the M means metric). Now let’s say the pitch is 1mm. The size of your screw is M4 x 1mm.
Let’s consider standard bolt sizes. For fasteners measured in inches, take the nominal major diameter and the threads per inch. For example, a 5/8-11 (coarse) thread means the nominal major diameter is 5/8"and the 11 means 11 threads per inch.
Metric vs standard chart
Metric or standard? Here’s how they compare:
|
Inches |
Metric Size- Pitch, ISO and IFI Rec. |
|
|
(UNC) |
(UNF) |
|
|
1- 64 |
1- 72 |
M2 x 0.4 |
|
3- 48 |
3- 56 |
M2.5 x 0.45 |
|
4- 40 |
4- 48 |
M3 x 0.5 |
|
6- 32 |
6- 40 |
M3.5 x 0.6 |
|
8- 32 |
8- 36 |
M4 x 0.7 |
|
10- 24 |
10- 32 |
M5 x 0.8 |
|
1/4- 20 |
1/4- 28 |
M 6x 1 |
|
5/16-18 |
5/16- 24 |
M8 x 1.25 |
|
3/8-16 |
3/8- 24 |
M10 x 1.5 |
|
7/16-14 |
7/16- 20 |
M12 x 1.75 |
|
1/2- 13 |
1/2- 20 |
M14 x 2 |
|
5/8- 11 |
5/8- 18 |
M18 x 2 |
|
3/4- 10 |
3/4- 16 |
M20 x 2.5 |
|
1- 8 |
1-12 |
M24 x 3 |
|
1-1/4- 7 |
1-1/8- 12 |
M30 x 3.5 |
|
1-1/2- 6 |
1-1/4- 12 |
M36 x 4 |
Fastener standards organizations
Standards are necessary to enable us to specify, test and assess fasteners’ properties. These are the organizations we’re covering in this article:
- ASTM International: Formerly known as the American Society for Testing and Materials, and informally called ASTM. They are a worldwide recognized leader in developing international standards. ASTM bolt standards and other fasteners almost always appear as ASTM/ASNI.
- ASME: The American Society for Testing and Materials. ASME is sometimes confused with ASTM. ASTM issues standards on material properties and testing, while ASME issues standards for materials to be used in construction and infrastructure.
- ANSI: American National Standards Institute. While ANSI does not develop standards, they oversee organizations that do.
- ISO: International Organization of Standardization, the world’s largest developer of international standards. The ISO standard lists are extensive, from ISO 4762 standard to ISO 7046 specifications.
- BSI: The British Standards Institution, along with ANSI, is a member of the ISO.
U.S. standards
Standards include ASTM/ANSI and ASME. You’ll notice in the STANDARD column that sometimes the letter M proceeds a standard. The M stands for metric. This is also spelled out in the THREAD column.
|
STANDARD |
DESCRIPTION |
THREAD |
MATERIAL |
|
A320L7 |
L7 Stud Bolt with Nut A320 |
UNC |
Steel |
|
A320L7 |
Stud Bolt |
UNC |
Stainless-Steel |
|
ASTMA193 |
B7 Stud Bolt with Nut A194 2H |
UNC |
Steel |
|
ASTMA193 |
Stud Bolt B8M with Nut A194 8M |
UNC |
Stainless-Steel |
|
B1.20.3 |
Socket Taper Pressure Pipe Plugs |
NPTF 3/4 Taper |
Alloy Steel Stainless-Steel Brass |
|
B1.20.3 |
Socket Taper Pressure Pipe Plugs |
NPTF 7/8 Taper |
Alloy Steel |
|
B1.5 |
Allthread ACME |
Inch |
Grade-5.8 Stainless-Steel-A2 |
|
B1.5 |
Round Flange Track Nut ACME Round Track Nut ACME |
Inch |
Steel |
|
B16.5 |
Flange Bolt |
UNC |
SAE-5(8.8) SAE-8(10.9) |
|
B18.15 |
Lifting Eye Nut Forged Type A |
UNC |
Steel |
|
B18.151A |
Eye Bolt Forged No Shoulder Type A |
UNC |
Steel |
|
B18.151B |
Eye Bolt Forged No Shoulder Type B |
UNC |
Steel |
|
B18.152A |
Lifting Eye Bolt Forged with Shoulder Collar |
UNC |
Steel |
|
B18.152B |
Lifting Eye Bolt Forged with Shoulder Collar |
UNC |
Steel |
|
B18.16.3M |
Nylon Insert Flange Self Locking Nut |
UNC |
Steel |
|
B18.2.1 |
Hexagon Head Bolt Hexagon Head Set Screw External Torx Bolt with Flange |
UNC |
SAE-5(8.8) SAE-8(10.9) |
|
B18.2.1 |
External Torx Bolt with Flange |
UNC |
Stainless-Steel 18/8-304-A2 Stainless-Steel 18/10-316-A4 |
|
B18.2.1 |
Hexagon Head Bolt Hexagon Head Set Screw |
UNF |
SAE-5(8.8) SAE-8(10.9) |
|
B18.2.1.1T10 |
Internal External Toothed Shakeproof Washer |
Inch |
Spring-Steel |
|
B18.2.1.1T6 |
Internal Toothed Shakeproof Washer |
Inch |
Spring-Steel |
|
B18.2.1.1T7 |
Internal Toothed Heavy Shakeproof Washer |
Inch |
Spring-Steel |
|
B18.2.1.1T9 |
Countersunk External Toothed Shakeproof Washer |
Inch |
Spring-Steel |
|
B18.2.1.1T10 |
Square Head Bolt |
UNC |
SAE-5(8.8) SAE-8(10.9) Mild Steel A-A563 Stainless-Steel 18/8-304-A2 Stainless-Steel 18/10-316-A4 |
|
B18.2.2 |
Hexagon Full Nut Hexagon Heavy Lock Nut Hexagon Heavy Nut Hexagon Lock Nut |
UNC |
SAE-5(8.8) SAE-8(10.9) Stainless-Steel 18/10-316-A4 |
|
B18.2.2 |
Hexagon Full Nut Hexagon Heavy Lock Nut Hexagon Heavy Nut Hexagon Lock Nut Hexagon Machine Screw Nut Hexagon Allthread Coupling Connector 3D |
UNC |
Mild Steel A-A563 Stainless-Steel 18/8-304-A2 |
|
B18.2.2 |
Hexagon Heavy Nut Hexagon Allthread Coupling Connector 3D |
UNC |
Steel-A194-2H Steel C-A563 |
|
B18.2.2 |
Hexagon Allthread Coupling Connector 3D |
UNC |
Dh-Steel Brass |
|
B18.2.2 |
Hexagon Structural Heavy Full Nut Slotted and Castle Hexagon Nut Slotted Hexagon Heavy Nut Slotted Hexagon Heavy Nut |
UNC |
Steel |
|
B18.2.2 |
Hexagon Full Nut Hexagon Heavy Lock Nut Hexagon Heavy Nut Hexagon Lock Nut |
UNF |
SAE-5(8.8) SAE-8(10.9) Mild Steel A-A563 |
|
B18.2.2 |
Hexagon Heavy Nut |
UNF |
Steel-A194-2H Steel C-A563 |
|
B18.2.2 |
Hexagon Full Nut Hexagon Heavy Lock Nut Hexagon Heavy Nut Hexagon Lock Nut |
UNF |
Stainless-Steel 18/8-304-A2 Stainless-Steel 18/10-316-A4 |
|
B18.2.2 |
Hexagon Full Nut Hexagon Heavy Lock Nut Hexagon Heavy Nut |
Left HandUNC |
SAE-8(10.9) |
|
B18.2.2 |
Hexagon Full Nut Hexagon Heavy Lock Nut Hexagon Heavy Nut Hexagon Lock Nut |
Left HandUNF |
SAE-5(8.8) SAE-8(10.9) Mild Steel A-A563SAE-5(8.8) Mild Steel A-A563 |
|
B18.2.2 |
Square Heavy Nut |
UNC |
Steel |
|
B18.2.2T1 |
Square Nut |
UNC |
Steel |
|
B18.2.5M |
12 Point Flange Head Bolt |
Metric Coarse |
Grade-8.8 Grade-10.9 Grade-12.9 Stainless-Steel-A2 Stainless-Steel-A4 |
|
B18.2.6 |
Hexagon Head Twist Off Tension Control Bolt Round Head Twist Off Tension Control Bolt |
UNC |
Steel-A325 |
|
B18.21.1 |
Single Coil Square Section Spring Washer Double Coil Rectangular Section Spring Washer External Toothed Heavy Shakeproof Washer |
Inch |
Spring-Steel |
|
B18.21.1T1 |
Single Coil Regular Section Spring Washer |
Inch |
Spring-Steel |
|
B18.21.1T2 |
Washer Spring, Heavy |
Inch |
Spring-Steel |
|
B18.21.1T3 |
Washer Spring, Extra Duty |
Inch |
Spring-Steel |
|
B18.21.1T4 |
Washer Spring, Hi Collar |
Inch |
Spring-Steel |
|
B18.21.1T8 |
External Toothed Shakeproof Washer |
Inch |
Spring-Steel |
|
B18.22.1 |
Narrow Washer Table 2B Regular Washer Table 2B SAE Narrow Washer Table 1A USS Wide Washer Table 1A Wide Washer Table 2B |
Inch |
Steel Stainless-Steel 18/8-304-A2 |
|
B18.22.1 |
Thin Washer Table 1B |
Inch |
Steel |
|
B18.22M |
American Flat Washer Narrow American Flat Washer Regular American Flat Washer Wide |
Metric |
Steel Stainless-Steel 18/8-304-A2 |
|
B18.3 |
Socket Cap Screw 1960 |
UNF |
Grade-12.9, Rc38/43 |
|
B18.3 |
Socket Set Screw Cone Point Socket Set Screw Cup Point Socket Set Screw Dog Point Socket Set Screw Flat Point Socket Set Screw Full Dog Point Socket Set Screw Oval Point Socket Set Screw Tip Brass Socket Set Screw Tip Nylon |
UNC |
Grade-14.9-45H |
|
B18.3 |
Low Head Socket Cap Screw |
UNC |
Steel |
|
B18.3 |
Socket Button Head Screw Socket Countersunk Screw Hexagon Socket Shoulder Screw Splined Socket Button Head Screw Spline Socket Countersunk Screw Torx Socket Button Head Screw Torx Socket Countersunk Screw |
UNC UNF |
Grade-12.9 |
|
B18.3 |
Socket Cap Screw 1960 |
UNC |
Grade-12.9, Rc38/43 |
|
B18.3 |
Hexagon Socket Shoulder Screw |
UNC |
Stainless-Steel |
|
B18.3 |
Low Head Socket Cap Screw |
UNC |
Stainless-Steel 18/10-316-A4 |
|
B18.3 |
Socket Cap Screw 1960 Socket Button Head Screw Socket Countersunk Screw |
UNC |
Stainless-Steel 18/8-304-A2 Brass Aluminium Monel Nylon-66 Phospher-Bronze |
|
B18.3 |
Socket Set Screw Tip Silver Socket Flange Cap Screw |
UNC |
Steel |
|
B18.3 |
Hexagon Keys Long Arm Hexagon Keys Short Arm |
Inch |
Steel Alloy Steel |
|
B18.3 |
Socket Set Screw Cone Point Socket Set Screw Cup Point Socket Set Screw Dog Point Socket Set Screw Flat Point Socket Set Screw Full Dog Point |
UNF |
Grade-14.9-45H |
|
B18.3 |
Socket Cap Screw 1960 Socket Button Head Screw Socket Countersunk Screw |
UNF |
Stainless-Steel 18/10-316-A4 Brass Aluminium Monel Nylon-66 Phosphor-Bronze |
|
B18.3.3M |
Hexagon Socket Shoulder Screw f9 |
Metric Coarse |
Grade-12.9 Stainless-Steel |
|
B18.31M |
Engineers Stud Metal End =1.1/2 D |
Metric Coarse |
Steel |
|
B18.5 |
Rib Neck Carriage Bolt Cup Square Neck Carriage Bolt |
UNC |
SAE-5(8.8) |
|
B18.5 |
Cup Square Neck Carriage Bolt Full Thread |
UNC |
SAE-8(10.9) |
|
B18.6.2 |
Square Head Set Screw Cone Pt Square Head Set Screw Cup Point Square Head Set Screw Half Dog Pt Square Head Set Screw Flat Pt Square Head Set Screw Oval Pt |
UNC |
Case Hardened Steel |
|
B18.6.2 |
Square Head Set Screw Cup Point |
UNC |
Alloy Steel Stainless-Steel |
|
B18.6.2 |
Slotted Grub (Set) Screw Flat Point |
UNC |
Grade-14.9-45H |
|
B18.6.2 |
Square Head Set Screw Cup Point |
UNF |
Case Hardened Steel |
|
B18.6.2 |
Slotted Grub (Set) Screw Flat Point |
UNF |
Grade-14.9-45H |
|
B18.6.3 |
Phillips Pan Head Screw Phillips Raised Countersunk Machine Screw Phillips Raised Trim Countersunk Machine Screw Slotted Cheese Head Machine Screw Phillips Countersunk Head Machine Screw Phillips 100 Deg Countersunk Head Machine Screw Phillips Trim Countersunk Head Machine Screw Slotted 100 Deg Countersunk Head Machine Screw Slotted Countersunk Head Machine Screw Slotted Pan Head Machine Screw |
UNC |
Grade-4.8 |
|
B18.6.3 |
Square Machine Screw Nut |
UNC |
Mild Steel A-A563 Stainless-Steel-A2 Brass |
|
B18.6.3 |
Slotted 100 Deg Countersunk Machine Screw Slotted Raised CountersunkMachine Screw Slotted Raised Countersunk Trim Machine Screw Pozi Raised Countersunk Machine Screw Pozi Raised Countersunk Trim Machine Screw Slotted Mushroom Head Machine Screw Phillips Mushroom Head Machine Screw Pozi Countersunk Head Machine Screw Pozi 100 Deg Countersunk Head Machine Screw Pozi Trim Countersunk Head Machine Screw Slotted Binding Head Machine Screw Pozi Binding Head Machine Screw Phillips Binding Head Machine Screw Pozi Raised Cheese Head Machine Screw Pozi Flange Pan Head Machine Screw Hexagon Head Machine Screw Hexagon Head Machine Screw Large Head Hexagon Head Slotted Machine Screw Hexagon Head Pozi Machine Screw Hexagon Head Phillips Machine Screw Hexagon Large Head Slotted Machine Screw Hexagon Large Head Pozi Machine Screw Hexagon Large Head Phillips Machine Screw Hexagon Washer Head Machine Screw Hexagon Washer Head Slotted Machine Screw Hexagon Washer Head Pozi Machine Screw Hexagon Washer Head Phillips Machine Screw Pozi Mushroom Head Machine Screw Pozi Pan Head Machine Screw Pozi Pan Washer Head Machine Screw Pozi Round Head Machine Screw Pozi Round Washer Head Machine Screw |
UNC |
Grade-4.8 |
|
B18.6.4 |
Pozi Pan Head Self Tapping Screw AB |
Inch |
Case Hardened Steel |
|
B18.6.9A |
Wing Nut, American Type A |
UNC |
Steel Cold Forged Stainless-Steel 18/8-304-A2 Stainless-Steel 18/10-316-A4 Brass Steel Cold Forged |
|
B18.6.9B1 |
Wing Nut, Mickey Mouse B1 |
UNC |
Steel Cold Forged Stainless-Steel 18/8-304-A2 Stainless-Steel 18/10-316-A4 Brass |
|
B18.6.9B2 |
Wing Nut, Mickey Mouse Tall B2 |
UNC |
Steel Cold Forged Stainless-Steel 18/8-304-A2 Stainless-Steel 18/10-316-A4 Brass |
|
B18.6.9C1 |
Wing Nut, American Type C1 Die Cast |
UNC |
Die Cast Zinc-Alloy |
|
B18.6.9C2 |
Wing Nut, American Type C2 Die Cast |
UNC |
Die Cast Zinc-Alloy |
|
B18.6.9C3 |
Wing Nut, American Type C3 Die Cast |
UNC |
Die Cast Zinc-Alloy |
|
B18.6.9D1 |
Wing Nut, American Type D1 Stamped |
UNC |
Steel |
|
B18.6.9D2 |
Wing Nut, American Type D2 Stamped |
UNC |
Steel |
|
B18.6.9D3 |
Wing Nut, American Type D3 Stamped |
UNC |
Steel |
|
B18.8.1 |
Split Cotter Pin |
Inch |
Steel |
|
B18.8.2 |
Parallel Dowel Pin |
Inch |
Hardened & Ground Steel |
|
B18.8.2 |
Spring Tension Pin Slotted |
Inch |
Spring-Steel Stainless-Steel |
|
B18.8.2 |
Parallel Dowel Pin |
Inch |
Stainless-Steel |
|
B18.8.2Coil |
Coiled Roll Spring Tension Pin Heavy Duty Coiled Roll Spring Tension Pin Light Duty Coiled Roll Spring Tension Pin Standard |
Inch |
Spring-Steel Stainless-Steel |
|
B18.9 |
Countersunk Nib Bolt |
UNC |
SAE-8(10.9) |
|
B18.9 |
Domed Countersunk Square Plow Bolt #3 |
UNC |
SAE-5(8.8) SAE-8(10.9) |
|
B18.9 |
Countersunk Square Plow Bolt |
UNC |
SAE-5(8.8) SAE-8(10.9) Grade-A(4.6) |
How do ISO standards compare?
Within the U.S., the metric system vs standard scenario can now be phrased as the metric system vs. metrics. ANSI is known for the imperial system, but also has metric standards, which differ slightly from ISO metric standards. The U.S. isn’t alone in converting to ISO with little enthusiasm. The Germans, who use their own metric standards (DIN), aren’t too excited either. The cost to convert is enormous when equipment and infrastructure are measured in the home system, so the reluctance is understandable. Still, if everyone wants more success exporting their products on the global stage, one metric standard for worldwide manufacturing is necessary.
The difference between these metric standards lies in the fasteners varying dimensional properties. These fastener specifications are slight. Yet these fasteners are interchangeable.
U.S. standards still require a pitch callout on coarse threads. Here’s how they compare to ISO designations:
|
ISO THREAD DESIGNATION |
U.S. EQUIVALENT |
|
M1.6 |
M1.6 x 0.35 |
|
M2 |
M2 x 0.4 |
|
M2.5 |
M2.5 x 0.45 |
|
M3 |
M 3x 0.5 |
|
M3.5 |
M3.5 x 0.6 |
|
M4 |
M4 x 0.7 |
|
M5 |
M5 x 0.8 |
|
M6 |
M6 x 1 |
|
M8 M8x1 |
M8 x 1.25 M8 x 1 |
|
M10 M10x1.25 |
M10 x 1.5 M10 x 1.25 |
|
M12 M12x1.25 |
M12 x 1.75 M12 x 1.25 |
|
M14 M14x1.5 |
M14 x 2 M14 x 1.5 |
|
M16 M16x1.5 |
M16 x 2 M16 x 1.5 |
|
M18 M18x1.5 |
M18 x 2.5 M18 x 1.5 |
|
M20 M20x1.5 |
M20 x 2.5 M20 x 1.5 |
|
M22 M22x1.5 |
M22 x 2.5 M22 x 1.5 |
|
M24 M24x2 |
M24 x 3 M24 x 2 |
|
M27 M27x2 |
M27 x 3 M27 x 2 |
|
M30 M30x2 |
M30 x 3.5 M30 x 2 |
|
M33 M33x2 |
M33 x 3.5 M33 x 2 |
|
M36 M36x3 |
M36 x 4 M36 x 3 |
|
M42 |
M42 x 4.5 |
|
M48 |
M48 x 5 |
|
M56 |
M56 x 5.5 |
|
M64 |
M64 x 6 |
|
M72 |
M72 x 6 |
|
M80 |
M80 x 6 |
|
M90 |
M90 x 6 |
|
M100 |
M100 x 6 |
What are British standards?
Fasteners made to British standards are still in use, but they’re primarily for the fastener aftermarket. So, for example, BS 4168 fasteners are still out there, but they’re not as readily available as fasteners made to ISO standards. You can also find BS 4183 dimensions so rest assured, you can still get British Standard fasteners.
However, the BSI is in the process of adopting all European standards as British standards – prefixed BS EN or BS ISO – and withdrawing conflicting BS fasteners. The BS fastener standard for inch washers is still popular, but most British fasteners use ISO or DIN standards. DIN is the Deutsches Institut für Normung, the German national organization for standardization.
We’ll show you equivalencies between BS, DIN and ISO, but first, here are British Standards:
|
STANDARD |
DESCRIPTION |
THREAD |
MATERIAL |
|
BS 21 |
Socket Taper Pressure Pipe Plugs |
BSPT 3/4 Taper |
Alloy Steel Stainless-Steel-A4 |
|
BS 57 |
Slotted Mushroom Head Machine Screw Slotted Cheese Head Machine Screw Pozi Countersunk Head Machine Screw Slotted Countersunk Head Machine Screw Slotted Raised Countersunk Machine Screw Pozi Raised Countersunk Machine Screw Slotted Pan Head Machine Screw |
BA |
Grade-4.8 |
|
BS 57 |
Hexagon Head Set Screw |
BA |
Grade-R |
|
BS 57 |
Hexagon Head Set Screw Hexagon Full Nut Hexagon Lock Nut |
BA |
Grade-A-Steel |
|
BS 57 |
Hexagon Head Set Screw |
BA |
Stainless-Steel-A2 |
|
BS 57 |
Hexagon Full Nut Hexagon Lock Nut |
BA |
Stainless-Steel |
|
BS 57 |
Hexagon Full Nut |
BA |
Brass |
|
BS 57 |
Pozi Mushroom Head Machine Screw Pozi Pan Head Machine Screw Slotted Round Head Machine Screw |
BA |
Grade-4.8 |
|
BS 325 |
Cup Head Nib Bolt |
BSW Whitworth |
Grade-4.6 |
|
BS 325 |
Black Square Nut |
BSW Whitworth |
Class-4 |
|
BS 325 |
Hexagon Black Full Nut |
BSW Whitworth |
Grade-A-Steel |
|
BS 325 |
Cup Square Neck Carriage Bolt with Nut Countersunk Square Plow Bolt Countersunk Long Square Plow Bolt For Wood Oval Neck Cup Head Bolts |
BSW Whitworth |
Grade-4.6 |
|
BS 450 |
Slotted Mushroom Head Machine Screw Slotted Cheese Head Machine Screw Slotted Countersunk Head Machine Screw Slotted Pan Head Machine Screw Slotted Raised Countersunk Machine Screw Slotted Raised Cheese Head Machine Screw |
BSF BSW Whitworth |
Grade-4.8 |
|
BS 450 |
Pozi Countersunk Head Machine Screw Pozi Raised Cheese Head Machine Screw Pozi Raised Countersunk Machine Screw Pozi Mushroom Head Machine Screw Pozi Pan Head Machine Screw Slotted Round Head Machine Screw |
BSF BSW Whitworth |
Grade-4.8 |
|
BS 450 |
Slotted Round Head Machine Screw |
BSW Whitworth |
Brass |
|
BS 856 |
Wing Nut Mickey Mouse Type DC Wing Nut Type CF |
BSF BSW Whitworth BA |
Steel Stainless-Steel Brass |
|
BS 1083 |
Hexagon Head Bolt Hexagon Head Set Screw |
BSW Whitworth |
Grade-R Stainless-Steel-A2 |
|
BS 1083 |
Hexagon Full Nut Hexagon Lock Nut |
BSW Whitworth |
Grade-A-Steel Stainless-Steel |
|
BS 1083 |
Hexagon Lock Nut Thicker 3 Sizes |
BSW Whitworth BSF |
Grade-A-Steel Stainless-Steel |
|
BS 1083 |
Slotted and Castle Hexagon Nut |
BSW Whitworth BSF |
Steel |
|
BS 1083 |
Hexagon Head Bolt Hexagon Head Set Screw |
BSF |
Grade-R Stainless-Steel-A2 |
|
BS 1083 |
Hexagon Full Nut Hexagon Lock Nut |
BSF |
Grade-A-Steel Stainless-Steel |
|
BS 1210 |
Pozi Countersunk Twin Thread Wood Screw |
Metric |
Steel |
|
BS 1210 |
Pozi Countersunk Wood Screw |
Inch |
Steel |
|
BS 2470 |
Socket Cap Screw 1936 |
UNF UNC |
Grade-12.9 Stainless-Steel 18/8-304-A2 |
|
BS 2470 |
Hexagon Keys Short Arm |
Inch |
Alloy Steel |
|
BS 2470 |
Socket Set Screw Cone Point Socket Set Screw Cup Point Socket Set Screw Dog Point Socket Set Screw Flat Point |
BSW Whitworth BSF BA |
Grade-14.9-45H |
|
BS 2470 |
Socket Cap Screw Socket Countersunk Screw Hexagon Socket Shoulder Screw |
BSW Whitworth |
Grade-X(12.9) |
|
BS 2470 |
Socket Cap Screw Socket Countersunk Screw |
BSW Whitworth BSF |
Stainless-Steel 18/8-304-A2 |
|
BS 2470 |
Socket Cap Screw Socket Countersunk Screw |
BSF BA |
Grade-X(12.9) Stainless-Steel 18/8-304-A2 |
|
BS 2693 |
Engineers Stud Metal End =1.1/2 D |
BSF BSW Whitworth |
Steel |
|
BS 3032 |
D Shackle Pins A D Shackle Pins C D Shackle Pins E D Shackle Pins F with Forelock Pin |
Inch |
Steel |
|
BS 3410 |
Inch Washer Table 1 BA Inch Washer Table 2 BA Inch Washer Table 3 Heavy Inch Washer Table 3 Light Inch Washer Table 4 Heavy Inch Washer Table 4 Light Inch Washer Table 5 Inch Washer Table 6 Inch Washer Table 7 Inch Washer Table 8 Inch Washer Table 9 |
Inch |
Steel Stainless-Steel Brass |
|
BS 3410 |
Inch Washer Table 1 BA |
Inch |
Nylon-66 |
|
BS 4162 |
Flange Bolt |
Metric Coarse |
Steel |
|
BS 4168 |
Hexagon Socket Shoulder Screw f9 |
Metric Coarse |
Grade-12.9 |
|
BS 4174 |
Slotted Countersunk Head Self Tapping Screw AB Slotted Countersunk Head Self Tapping Screw B Slotted Raised Countersunk Head Self Tapping Screw AB Slotted Raised Countersunk Head Self Tapping Screw B Hexagon Head Self Tapping Screw AB Hexagon Head Self Tapping Screw B Pozi Countersunk Head Self Tapping Screw AB Pozi Countersunk Head Self Tapping Screw B Pozi Pan Head Self Tapping Screw AB Pozi Pan Head Self Tapping Screw B Slotted Pan Head Self Tapping Screw AB Slotted Pan Head Self Tapping Screw B |
Inch |
Case Hardened Steel |
|
BS 4174 |
Round Hammer Drive Screw 'U' |
Inch |
Steel Stainless-Steel-A2 Brass Copper |
|
BS 4183 |
Hexagon Machine Screw Nut |
Metric Coarse |
Steel |
|
BS 4278 |
Lifting Eye Bolt Forged with Shoulder Collar |
UNC |
Steel |
|
BS 4320 |
Form B Flat Washer Form C Flat Washer Form D Flat Washer Form E Flat Washer Form F Flat Washer Form G Flat Washer Table 6 Washer Greater Than M68 |
Metric |
Steel |
|
BS 4320 |
Form B Flat Washer Form C Flat Washer Form D Flat Washer Form E Flat Washer Form F Flat Washer Form G Flat Washer |
Metric |
Stainless-Steel |
|
BS 4320 |
Form B Flat Washer Form C Flat Washer |
Metric |
Brass Nylon-66 |
|
BS 4320 |
Form B Flat Washer |
Metric |
Aluminium Polypropylene Titanium |
|
BS 4439 |
Engineers Stud Metal End =1.1/2 D 4H |
Metric Coarse |
Grade-8.8 Grade-10.9 Grade-12.9 Grade-4.6 Stainless-Steel |
|
BS 4463 |
Double Dished (Wave) Crinkle Washer |
Metric |
Beryllium Copper |
|
BS 4929 |
Nylon Insert Self Locking P-Type Thick Nut |
UNC UNF |
Class-8 |
|
BS 4929 |
Nylon Insert Self Locking T Type Thin Nut |
UNC UNF |
Class-8 |
|
BS 4933 |
Cup Square Neck Carriage Bolt with Nut |
Metric Coarse |
Steel |
|
BS 7419 |
Square Square Holding Down Bolts |
Metric Coarse |
Grade-4.6 Grade-8.8 |
|
BS 1802A |
Single Coil Square Section Spring Washer |
Inch |
Spring-Steel Stainless-Steel |
|
BS 1802A |
Single Coil Square Section Spring Washer |
BA |
Spring-Steel |
|
BS 1802B |
Rectangular Section Spring Washer |
Inch |
Spring-Steel Stainless-Steel |
|
BS 1802B |
Rectangular Section Spring Washer |
BA |
Spring-Steel |
|
BS 1802D |
Double Coil Rectangular Section Spring Washer |
Inch |
Spring-Steel |
|
BS 3032T1 |
D Shackles Small with A Pin |
Inch |
Steel |
|
BS 3032T2 |
D Shackles Large with A Pin |
Inch |
Steel |
|
BS 3032T3 |
D Shackles Large Bow with A Pin |
Inch |
Steel |
|
BS 3032T4 |
D Shackles Small Bow with A Pin |
Inch |
Steel |
|
BS 3974G |
U' Bolt Round Bend To Grip |
Metric Coarse |
Steel Stainless-Steel |
|
BS 3974NG |
'U' Bolt Round Bend Not To Grip |
Metric Coarse |
Steel Stainless-Steel |
|
BS 4278T1 |
Lifting Eye Bolt Forged with Shoulder Collar |
Metric Coarse |
Steel |
|
BS 4278T2 |
Link Eye Bolt Forged with Shoulder Collar |
Metric Coarse |
Steel |
|
BS 4278T3 |
Dynamo Eye Bolt Forged with Shoulder Collar |
Metric Coarse |
Steel |
|
BS 4278T4 |
Lifting Eye Bolt Forged with Shoulder Collar |
BSW Whitworth |
Steel |
|
BS 4278T5 |
Link Eye Bolt Forged with Shoulder Collar |
BSW Whitworth UNC |
Steel |
|
BS 4278T6 |
Dynamo Eye Bolt Forged with Shoulder Collar |
BSW Whitworth UNC |
Steel |
|
BS 7670T3 |
Weld Screw 3 Nibs Under Head |
Metric |
Steel |
|
BS 7670T4 |
Hexagon Weld Nut Standard Collar |
Metric Coarse |
Steel |
|
BSP |
Hexagon Pipe Lock Nut |
Metric Coarse |
Steel |
Comparing DIN, ISO and British Standards
ISO 4762 vs DIN 912 – or are they the same? Is there a British equivalent for DIN 931? What’s DIN 934 or ISO 2340 equivalent to? What’s the din 6914 ISO equivalent? The chart below should help you answer these and other questions.
|
DIN Standard |
ISO Standard |
British Standard |
Product |
|
DIN 1 |
ISO 2339 |
Cone Pins, untempered |
|
|
DIN 125 |
ISO 7089 |
Washers; medium type, primarily for hexagon bolts |
|
|
DIN 125 |
ISO 7090 |
Washers; medium type, primarily for hexagon bolts |
|
|
DIN 126 |
ISO 7091 |
Product grade C washers - designed for use with hexagon head bolts and nut |
|
|
DIN 127 |
BS4464B |
Spring lock washers with square ends or tang ends |
|
|
DIN 128 |
Curved and wave spring lock washers |
||
|
DIN 137 |
Spring washers, curved or wave |
||
|
DIN 1440 |
ISO 8738 |
Medium type washers for pins |
|
|
DIN 1443 |
ISO 2340 |
Clevis pins without head |
|
|
DIN 1444 |
ISO 2341 |
Clevis pins with head |
|
|
DIN 1470 |
ISO 8739 |
Grooved Pins, Full Length Parallel-grooved with Pilot |
|
|
DIN 1471 |
ISO 8744 |
Grooved Pins, Full Length Taper-grooved |
|
|
DIN 1472 |
ISO 8745 |
Grooved Pins, Half Length Taper-grooved |
|
|
DIN 1473 |
ISO 8740 |
Grooved Pins, Full Length Parallel-grooved with Chamfer |
|
|
DIN 1474 |
ISO 8741 |
Grooved Pins, Half Length Reverse-grooved |
|
|
DIN 1475 |
ISO 8742 |
Grooved Pins, Third Length Centre-grooved |
|
|
DIN 1476 |
ISO 8746 |
Round Head Grooved Pins |
|
|
DIN 1477 |
ISO 8747 |
Countersunk Head Grooved Pins |
|
|
DIN 1481 |
ISO 8752 |
Spring-Type Straight Pins (Roll Pins) - Heavy Type |
|
|
DIN 1587 |
Hexagon domed cap nuts |
||
|
DIN 1816 |
Round Nut with Set Pin Holes Inside; ISO Metric Fine Thread |
||
|
DIN 315 |
Wing nuts with rounded wings |
||
|
DIN 316 |
Wing screws with rounded wings |
||
|
DIN 404 |
Slotted capstan screws |
||
|
DIN 417 |
ISO 7435 |
Slotted set screws with long dog point |
|
|
DIN 427 |
ISO 2342 |
Slotted headless screws with chamfered end |
|
|
DIN 428 |
ISO 4034 |
Hexagon nuts, Grade C |
|
|
DIN 433 |
ISO 7092 |
Washers for use with cheese head screws |
|
|
DIN 433-1 |
ISO 7092 |
Product grade A washers - with a hardness up to 250 HV designed for use with cheese head screws |
|
|
DIN 433-2 |
ISO 7092 |
Product grade A washers - with a hardness up to 300 HV designed for use with cheese head screws |
|
|
DIN 438 |
ISO 7436 |
Slotted set screws with cup point |
|
|
DIN 439 |
ISO 4035 |
BS3692 |
Hexagon thin nuts |
|
DIN 439 |
ISO 4036 |
BS3692 |
Hexagon thin nuts |
|
DIN 439 |
ISO 8675 |
BS3692 |
Hexagon thin nuts |
|
DIN 439-1 |
ISO 4036 |
Unchamfered hexagon thin nuts - Product grade B |
|
|
DIN 439-2 |
ISO 4035 |
Chamfered hexagon thin nuts - Product grades A and B |
|
|
DIN 439-2 |
ISO 8675 |
Chamfered hexagon thin nuts - Product grades A and B |
|
|
DIN 440 |
ISO 7094 |
Washers for use in timber constructions |
|
|
DIN 444 |
Eyebolts |
||
|
DIN 462 |
Machine Tools; Internal Tab Washers for Slotted Round Nuts for Hook Spanner according to DIN 1804 |
||
|
DIN 464 |
Knurled thumb screws, high type |
||
|
DIN 466 |
Knurled nuts, high type |
||
|
DIN 467 |
Knurled nuts, low type |
||
|
DIN 471 |
Circlips (retaining rings) for shafts; Normal type and heavy type |
||
|
DIN 479 |
Square head bolts with short dog point |
||
|
DIN 5406 |
Lockwashers and locking plates for use with rolling bearings |
||
|
DIN 548 |
Round nuts with set pin holes in side |
||
|
DIN 551 |
ISO 4766 |
Slotted set screws with flat point |
|
|
DIN 553 |
ISO 7434 |
Slotted set screws with cone point |
|
|
DIN 555 |
ISO 4034 |
M5 to M100x6 hexagon nuts - Product grade C |
|
|
DIN 558 |
ISO 4018 |
Hexagon head screws |
|
|
DIN 580 |
Collar eyebolts for lifting purposes |
||
|
DIN 601 |
ISO 4016 |
M5 to M52 hexagon head bolts; product grade C |
|
|
DIN 603 |
Mushroom head square neck bolts |
||
|
DIN 609 |
Hexagon fits bolts with long thread |
||
|
DIN 6319 |
Spherical washers and conical seats |
||
|
DIN 6325 |
ISO 8734 |
Parallel Pins, Hardened; Tolerance Zone m6 |
|
|
DIN 6340 |
Washers for clamping devices |
||
|
DIN 653 |
Knurled thumb screws, low type |
||
|
DIN 6797 |
Toothed lock washers |
||
|
DIN 6798 |
Serrated lock washers |
||
|
DIN 6799 |
Lock washers (retaining washers) for shafts |
||
|
DIN 6900 |
ISO 10644 |
Screw and Washer Assemblies |
|
|
DIN 6901 |
ISO 10510 |
Tapping screw and washer assemblies |
|
|
DIN 6902 |
ISO 10673 |
Plain washers for screw and washer assemblies |
|
|
DIN 6903 |
ISO 10669 |
Plain washers for tapping screw and washer assemblies |
|
|
DIN 6912 |
Hexagon socket thin head cap screws with pilot recess |
||
|
DIN 6914 |
ISO 14399-4 |
High-strength hexagon head bolts with large widths across flats for structural steel bolting |
|
|
DIN 6916 |
Round washers for high-strength structural steel bolting |
||
|
DIN 6921 |
ISO 1665 |
Hexagon flange bolts |
|
|
DIN 6922 |
ISO 1665 |
Hexagon flange bolts with reduced shank |
|
|
DIN 6923 |
ISO 1661 |
Hexagon nuts with flange |
|
|
DIN 6924 |
ISO 7040 |
Prevailing torque type hexagon nuts with non-metallic insert |
|
|
DIN 6924 |
ISO 10512 |
Prevailing torque type hexagon nuts with non-metallic insert |
|
|
DIN 6925 |
ISO 7042 |
Prevailing torque type all-metal hexagon nuts |
|
|
DIN 6925 |
ISO 10513 |
Prevailing torque type all-metal hexagon nuts |
|
|
DIN 6926 |
ISO 7043 |
Prevailing torque type hexagon nuts with flange and with non-metallic insert |
|
|
DIN 6926 |
ISO 12125 |
Prevailing torque type hexagon nuts with flange and with non-metallic insert |
|
|
DIN 6927 |
ISO 7044 |
Prevailing torque type all-metal nuts with flange |
|
|
DIN 6927 |
ISO 12126 |
Prevailing torque type all-metal nuts with flange |
|
|
DIN 7045 |
Pan head screws with type H or type Z cross recess - product grade A |
||
|
DIN 7337 |
ISO 14589 |
Break mandrel blind rivets |
|
|
DIN 7337 |
ISO 15977 to ISO 15984 |
Break mandrel blind rivets |
|
|
DIN 7337 |
ISO 16582 to ISO 16584 |
Break mandrel blind rivets |
|
|
DIN 7343 |
ISO 8750 |
Spiral Pins; Normal Type |
|
|
DIN 7344 |
ISO 8748 |
Spiral Pins; Heavy Duty Type |
|
|
DIN 7346 |
ISO 13337 |
Spring-Type Straight Pins; (Roll Pins) Light-weight Type |
|
|
DIN 7349 |
Plain Washers for Bolts with Heavy Clamping Sleeves |
||
|
DIN 7500-1 |
ISO 7085 |
Thread rolling screws for metric ISO thread - Part 1: Types, designation, requirements |
|
|
DIN 7500-2 |
Thread rolling screws for ISO metric thread; guideline values for hole diameters |
||
|
DIN 7504 |
Self-drilling screws with tapping screw thread - Dimensions, requirements and testing |
||
|
DIN 7513 |
Hexagon head and slotted head thread cutting screws - Dimensions, requirements and testing |
||
|
DIN 7516 |
Cross recessed head thread cutting screws - Dimensions, requirements and testing |
||
|
DIN 7603 |
Ring seals and gaskets |
||
|
DIN 7970 |
ISO 1478 |
Threads and thread ends for tapping screws (modified version of ISO 1478) |
|
|
DIN 7971 |
ISO 1481 |
BS4174 |
Slotted pan head tapping screws |
|
DIN 7972 |
ISO 1482 |
Slotted countersunk head tapping screws |
|
|
DIN 7973 |
ISO 1483 |
Slotted raised countersunk head tapping screws |
|
|
DIN 7977 |
ISO 8737 |
Taper Pins with Thread Ends and Constant Point Lengths |
|
|
DIN 7978 |
ISO 8736 |
Taper Pins with Internal Thread |
|
|
DIN 7979 |
ISO 8733 |
Parallel Pins with Internal Thread |
|
|
DIN 7979 |
ISO 8735 |
Parallel Pins with Internal Thread |
|
|
DIN 7980 |
BS4464A |
Spring lock washers with square ends for cheese head screws |
|
|
DIN 7981 |
ISO 7049 |
Cross recessed pan head tapping screws |
|
|
DIN 7982 |
ISO 7050 |
Cross recessed countersunk head tapping screws |
|
|
DIN 7983 |
ISO 7051 |
Countersunk (Flat) Head Tapping Screws with Cross Recess |
|
|
DIN 7984 |
Hexagon socket thin head cap screws |
||
|
DIN 7985 |
ISO 7045 |
BS4183 |
Cross recessed raised Phillips Pan head screws |
|
DIN 7989-1 |
Washers for steel structures - Product grade C |
||
|
DIN 7989-2 |
Washers for steel structures - Product grade A |
||
|
DIN 7991 |
ISO 10642 |
BS4168 |
Hexagon socket countersunk head cap screws |
|
DIN 84 |
ISO 1207 |
BS4183 |
Product grade A slotted cheese head screws |
|
DIN 85 |
ISO 1580 |
BS4183 |
Product grade A slotted pan head screws |
|
DIN 9021 |
ISO 7093 |
Plain washers with large outside diameter |
|
|
DIN 908 |
Hexagon socket screw plugs with parallel screw thread |
||
|
DIN 910 |
Hexagon-duty hexagon head screw plugs |
||
|
DIN 911 |
ISO 2936 |
Hexagon Socket Screw Keys |
|
|
DIN 912 |
ISO 4762 |
BS4168 |
Hexagon socket head cap screws (modified version of ISO 4762) |
|
DIN 912 |
ISO 21268 |
BS4168 |
Hexagon socket head cap screws (modified version of ISO 4762) |
|
DIN 913 |
ISO 4026 |
Hexagon socket set screws with flat point (ISO 4026 modified) |
|
|
DIN 914 |
ISO 4027 |
Hexagon socket set screws with cone point (ISO 4029 modified) |
|
|
DIN 915 |
ISO 4028 |
Hexagon socket set screws with full dog point |
|
|
DIN 916 |
ISO 4029 |
Hexagon socket set screws with cup point (ISO 4029 modified) |
|
|
DIN 918-3 |
Overview of European Standards for fasteners |
||
|
DIN 921 |
Slotted pan head screws with large head |
||
|
DIN 923 |
Slotted pan head screws with shoulder |
||
|
DIN 929 |
Hexagon weld nuts |
||
|
DIN 93 |
Tab washers with long tab |
||
|
DIN 930 |
Fine thread pitch partially threaded screws |
||
|
DIN 931-1 |
ISO 4014 |
BS3692 |
M1,6 to M39 Hexagon Cap Screws Partially Threaded - Product grades A and B |
|
DIN 931-2 |
ISO 4014 |
BS3692 |
M42 to M160x6 Hexagon Cap Screws Partially Threaded - Product grade B |
|
DIN 933 |
ISO 4017 |
BS3692 |
M1,6 to M52 Hexagon Cap Screws Fully Threaded - Product grades 8.8 |
|
DIN 934 |
ISO 4032 |
Hexagon nuts with metric coarse and fine pitch thread - Product classes A and B |
|
|
DIN 934 |
ISO 8673 |
Hexagon nuts with metric coarse and fine pitch thread - Product classes A and B |
|
|
DIN 935-1 |
Hexagon slotted nuts and castle nuts with metric coarse and fine pitch thread - Product grades A and B |
||
|
DIN 935-2 |
M42 to M160x6 hexagon head bolts; product grade B |
||
|
DIN 935-3 |
Hexagon slotted nuts with metric coarse pitch thread - Product grade C |
||
|
DIN 936 |
BS3692 |
M8 to M52 and M8x1 to M52x3 hexagon thin nuts; product grades A and B |
|
|
DIN 937 |
Hexagon thin castle nuts |
||
|
DIN 938 |
Studs with a length of engagement equal to about 1 d |
||
|
DIN 939 |
Studs with a length of engagement equal to about 1,25 d |
||
|
DIN 94 |
ISO 1234 |
Split pins |
|
|
DIN 95 |
Slotted Raised Countersunk (Oval) Head Wood Screws |
||
|
DIN 96 |
Slotted Round Head Wood Screws |
||
|
DIN 960 |
ISO 8765 |
M8x1 to M100x4 hexagon head bolts with fine pitch thread - Product grades A and B |
|
|
DIN 960 |
ISO 8676 |
M8x1 to M100x4 hexagon head bolts with fine pitch thread - Product grades A and B |
|
|
DIN 961 |
ISO 8676 |
M8x1 to M52x3 hexagon head bolts with fine pitch thread - Product grades A and B |
|
|
DIN 962 |
Designation system for fasteners |
||
|
DIN 963 |
ISO 2009 |
BS3692 |
Slotted countersunk head screws (with countersunk heads as specified in ISO 2009-1972) |
|
DIN 964 |
ISO 2010 |
BS3692 |
Slotted raised countersunk oval head screws |
|
DIN 965 |
ISO 7046 |
BS3692 |
Cross recessed countersunk flat head screws |
|
DIN 966 |
ISO 7047 |
Cross recessed raised countersunk head screws |
|
|
DIN 970 |
ISO 4032 |
Hexagon nuts; Style 1; Metric coarse thread, Product grades A and B; ISO 4032 modified |
|
|
DIN 971-1 |
ISO 8673 |
Style 1 hexagon nuts with metric fine pitch thread; property classes 6 and 8 |
|
|
DIN 971-2 |
ISO 8674 |
Style 2 hexagon nuts with metric fine pitch thread; property classes 10 and 12 |
|
|
DIN 972 |
ISO 4034 |
M5 to M39 hexagon nuts; style 1; product grade C (modified version of ISO 4034) |
|
|
DIN 975 |
Threaded rods |
||
|
DIN 976-1 |
Metric thread stud bolts |
||
|
DIN 976-2 |
Metric interference-fit thread stud bolts |
||
|
DIN 977 |
ISO 21670 |
Hexagon weld nuts with flange |
|
|
DIN 979 |
Hexagon thin slotted nuts and castle nuts with metric coarse and fine pitch thread - Product grades A and B |
||
|
DIN 980 |
ISO 7042 |
All-metal prevailing torque type hexagon nuts |
|
|
DIN 980 |
ISO 10513 |
All-metal prevailing torque type hexagon nuts |
|
|
DIN 981 |
Locknuts for use with rolling bearings |
||
|
DIN 982 |
ISO 7040 |
Prevailing torque type hexagon nuts with non-metallic insert |
|
|
DIN 982 |
ISO 10512 |
Prevailing torque type hexagon nuts with non-metallic insert |
|
|
DIN 983 |
Retaining rings with lugs for use on shafts (external circlips) |
||
|
DIN 985 |
ISO 10511 |
Prevailing torque type hexagon thin nuts with non-metallic insert |
|
|
DIN 986 |
Prevailing torque type hexagon domed cap nuts with non-metallic insert |
||
|
DIN 988 |
Shim rings and supporting rings |
Note: this is a rough guide and you should always carry out your own trials to ensure you have the right fastener for your application.
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