Technical & standards.
Fastener standards, charts and calculators for the bench: bolt finder, torque and weight calculators, grades, markings, threads, coatings and corrosion. Start with the bolt finder →

Fastener standards & calculators
Find a size and its dimensions to DIN, ISO, IS and NF E, check threads, grades and markings, work out torque and weight, choose rivet nuts and blind rivets, then check coatings and corrosion.
Bolt finder
Pick a metric size to see everything about it at once.
Fastener dimensions to DIN, ISO, IS and NF E
93 fastener types covering the standards on our DIN chart: bolts and machine screws, tapping and wood screws, studs, eye bolts, nuts, washers, pins, circlips, rivets, threaded rod and the French NF E standard fasteners (hex bolts, hex nuts, heavy flange bolts, Z / M / L / LL plain washers, CS and CL conical washers). Where DIN, ISO, IS and NF E differ, each standard has its own tab and the values that change are shaded, so you can see at a glance which sizes are not interchangeable. Click any row to update the drawing.
For information only. Values are nominal, taken from the standards as published (checked October 2026). Standards are revised: always check the current edition named on your drawing before production or inspection.
Thread, drill and clearance hole chart
Metric ISO threads. Clearance holes per ISO 273: fine for accurate location, medium for general use, coarse for site work.
| Thread | Coarse pitch | Fine pitch | Tapping drill | Clearance fine | Clearance medium | Clearance coarse | Spanner ISO (DIN) | Allen key (cap screw) |
|---|---|---|---|---|---|---|---|---|
| M3 | 0.5 | 0.35 | 2.5 | 3.2 | 3.4 | 3.6 | 5.5 | 2.5 |
| M4 | 0.7 | 0.5 | 3.3 | 4.3 | 4.5 | 4.8 | 7 | 3 |
| M5 | 0.8 | 0.5 | 4.2 | 5.3 | 5.5 | 5.8 | 8 | 4 |
| M6 | 1.0 | 0.75 | 5.0 | 6.4 | 6.6 | 7.0 | 10 | 5 |
| M8 | 1.25 | 1.0 | 6.8 | 8.4 | 9.0 | 10.0 | 13 | 6 |
| M10 | 1.5 | 1.25 / 1.0 | 8.5 | 10.5 | 11.0 | 12.0 | 16 (17) | 8 |
| M12 | 1.75 | 1.5 / 1.25 | 10.2 | 13.0 | 13.5 | 14.5 | 18 (19) | 10 |
| M14 | 2.0 | 1.5 | 12.0 | 15.0 | 15.5 | 16.5 | 21 (22) | 12 |
| M16 | 2.0 | 1.5 | 14.0 | 17.0 | 17.5 | 18.5 | 24 | 14 |
| M18 | 2.5 | 1.5 | 15.5 | 19.0 | 20.0 | 21.0 | 27 | 14 |
| M20 | 2.5 | 1.5 | 17.5 | 21.0 | 22.0 | 24.0 | 30 | 17 |
| M22 | 2.5 | 1.5 | 19.5 | 23.0 | 24.0 | 26.0 | 34 (32) | 17 |
| M24 | 3.0 | 2.0 | 21.0 | 25.0 | 26.0 | 28.0 | 36 | 19 |
| M27 | 3.0 | 2.0 | 24.0 | 28.0 | 30.0 | 32.0 | 41 | 19 |
| M30 | 3.5 | 2.0 | 26.5 | 31.0 | 33.0 | 35.0 | 46 | 22 |
| M36 | 4.0 | 3.0 | 32.0 | 37.0 | 39.0 | 42.0 | 55 | 27 |
Inch (UNC / UNF) sizes and nearest metric
For imported machinery and US drawings. Do not mix inch and metric threads: they may start but will strip.
| Size | Diameter (mm) | UNC (TPI) | UNF (TPI) | Nearest metric | Spanner (in) |
|---|---|---|---|---|---|
| #10 | 4.83 | 24 | 32 | M5 | 3/8 |
| 1/4" | 6.35 | 20 | 28 | M6 | 7/16 |
| 5/16" | 7.94 | 18 | 24 | M8 | 1/2 |
| 3/8" | 9.53 | 16 | 24 | M10 | 9/16 |
| 7/16" | 11.11 | 14 | 20 | M11 / M12 | 5/8 |
| 1/2" | 12.70 | 13 | 20 | M12 | 3/4 |
| 5/8" | 15.88 | 11 | 18 | M16 | 15/16 |
| 3/4" | 19.05 | 10 | 16 | M20 | 1-1/8 |
| 7/8" | 22.23 | 9 | 14 | M22 | 1-5/16 |
| 1" | 25.40 | 8 | 12 (14 UNS) | M24 | 1-1/2 |
Property classes: steel bolts and nuts
ISO 898-1 (IS 1367 Part 3 in India). Read the class as two numbers: the first × 100 is the minimum tensile strength in MPa, and the first × second × 10 is the minimum yield. A 10.9 bolt: 1000 MPa tensile, 90% of that as yield.
| Class | Min. tensile (MPa) | Min. yield / 0.2% proof (MPa) | Proof stress (MPa) | Core hardness | Matching nut | Typical use |
|---|---|---|---|---|---|---|
| 4.6 | 400 | 240 | 225 | 67–95 HRB | Class 5 | Light fabrication, non-critical |
| 5.6 | 500 | 300 | 280 | 74–95 HRB | Class 5 | General fabrication |
| 8.8 (≤ M16) | 800 | 640 | 580 | 22–32 HRC | Class 8 | Structural and general engineering |
| 8.8 (> M16) | 830 | 660 | 600 | 23–34 HRC | Class 8 | Structural and general engineering |
| 10.9 | 1040 | 940 | 830 | 32–39 HRC | Class 10 | Machinery, automotive, high-load joints |
| 12.9 | 1220 | 1100 | 970 | 39–44 HRC | Class 12 | Socket cap screws, dies and tooling |
Rule: always use a nut of the same or higher class than the bolt. A weaker nut strips before the bolt reaches its strength.
Reading head markings
Metric steel bolts from M5 up carry the class and the maker's mark on the head. Stainless shows the grade. Inch (SAE) bolts use radial lines instead of numbers.
Stainless steel grades
ISO 3506-1. The letter and digit give the steel group, the number after the dash × 10 gives the minimum tensile strength in MPa.
| Grade | Steel | Min. tensile (MPa) | Min. 0.2% proof (MPa) | Corrosion | Where to use |
|---|---|---|---|---|---|
| A1-70 | 303 (free machining) | 700 | 450 | Fair | Indoor, dry |
| A2-70 | 304 | 700 | 450 | Good | General outdoor, food machinery, buildings |
| A4-70 | 316 | 700 | 450 | Very good | Coastal, marine, chemical and pharma |
| A4-80 | 316 | 800 | 600 | Very good | Stronger marine and chemical joints |
| C1-70 | 410 (martensitic) | 700 | 410 | Fair | Hardened self-drilling screws |
| Duplex D4 / 2205 | 1.4462 | 800 | 600 | Excellent | Offshore, desalination, high chlorides |
Quick choice: dry indoors, A2 is enough. Near the sea, swimming pools or chemicals, use A4. Stainless threads can gall; use anti-seize on A2 / A4 nuts and bolts.
ASTM studs and nuts for pressure service
Common pairings for flanges, valves and pressure vessels.
| Stud | Material | Min. tensile | Matching nut | Service |
|---|---|---|---|---|
| A193 B7 | Cr-Mo alloy steel | 125 ksi (860 MPa), up to 2½" | A194 2H | High temperature and pressure |
| A193 B7M | Cr-Mo, hardness-limited | 100 ksi (690 MPa) | A194 2HM | Sour (H₂S) service, NACE MR0175 |
| A193 B16 | Cr-Mo-V alloy steel | 125 ksi (860 MPa), up to 2½" | A194 4 / 7 | Higher temperature than B7 |
| A193 B8 / B8M | SS 304 / SS 316 | 75 ksi (515 MPa), class 1 | A194 8 / 8M | Corrosive service |
| A320 L7 | Cr-Mo alloy steel | 125 ksi (860 MPa), up to 2½" | A194 4 / 7 | Low temperature, down to −101 °C |
| A453 660 | A286 superalloy | 130 ksi (895 MPa) | A453 660 | Very high temperature |
Hardness conversion (approximate)
Useful when a drawing and a test certificate use different scales. Values per ASTM E140 tables, rounded.
| Rockwell C (HRC) | Rockwell B (HRB) | Vickers (HV) | Brinell (HB) | Approx. tensile (MPa) |
|---|---|---|---|---|
| — | 60 | 110 | 107 | ~370 |
| — | 70 | 125 | 122 | ~420 |
| — | 80 | 150 | 145 | ~500 |
| — | 90 | 185 | 176 | ~600 |
| 20 | ~98 | 238 | 226 | ~770 |
| 25 | — | 266 | 253 | ~860 |
| 30 | — | 302 | 286 | ~960 |
| 35 | — | 345 | 327 | ~1110 |
| 40 | — | 392 | 371 | ~1250 |
| 45 | — | 446 | 421 | ~1450 |
| 50 | — | 513 | 481 | ~1700 |
Tightening torque calculator
Preload is set to 75% of the proof load (ISO 898-1 proof stress for steel, 0.2% proof stress for stainless). Torque = K × preload × diameter.
For guidance only. Follow the torque given on your drawing or by the equipment maker, and use a calibrated torque wrench.
Fastener weight calculator
Choose any DIN, ISO, IS or NF E standard, then the size, length and material, to get the weight per piece, per 100 and per 1000, and how many pieces make a kilo. Useful for quotes, dispatch and freight.
- Standard table the mass published for that standard (kg per 1000 pcs, steel 7.85 g/cm³), for 46 standards including DIN 931, 933, 912, 934, 985, 125, 9021, 127, 7991, 7985, 965, 913, 916, 7984, 6912, 603, 6921, 84, 7, 1481, 471, 472, 975, 580 and 582. Between two listed lengths the value is interpolated; beyond the longest listed length it is extended at the table’s own weight per mm.
- Table-corrected no table for this exact standard or length: calculated from its own dimensions, then corrected with the published table of the same part (for example ISO 4014 with DIN 931, ISO 4032 with DIN 934). Typically within ±2–3 %.
- Calculated no published table exists: calculated from the standard’s dimensions, with the tolerance shown.
Rivet nut (nut insert) selector
Work through the steps the way the big fastener catalogues do: application, material, head, body, end, thread and grip. Every part number, grip range and length comes from our own size tables.
Application
Rivet nut material
Head style
Body & end
Thread
Sheet thickness
Matching parts
Which type do I need?
Hole Ø equals the body Ø with tolerance +0.1 / 0; hex bodies need a hex hole across flats. Before production, set the tool stroke with a trial setting in your own sheet.
Blind rivet (pop rivet) selector
Choose the rivet type, diameter and material, then the thickness and material of your parts. You get the drill size, a suggested length, the strength per rivet, how many rivets your load needs, and a design check for the joint.
Rivet type
Diameter
Rivet material
Parts material
Total thickness (grip)
Joint load
Joint design check
Which rivet do I need?
Strengths are typical minimum values per rivet from our product data. Head and mandrel dimensions are typical for dome heads to ISO 15977. The suggested length is a rule of thumb (grip + about 1 × d); confirm against the grip chart for production.
Sheet metal fasteners: holes and sheet hardness
Self-clinching parts must be harder than the sheet. Blind rivets and rivet nuts need the right hole: too small and they will not enter, too big and they spin.
| Sheet | Typical hardness | Clinch fastener to use |
|---|---|---|
| Aluminium | HRB ≤ 50 | Aluminium, steel or stainless clinch fasteners |
| Mild steel / CRCA | HRB ≤ 70–80 | Steel or stainless clinch fasteners |
| Stainless 304 / 316 | HRB ≤ 88–92 | Hardened 400-series or A286 clinch fasteners |
| Size | Blind rivet hole | Rivet nut thread | Rivet nut hole (round) |
|---|---|---|---|
| 2.4 mm | 2.5 | M3 | 5.0 |
| 3.2 mm | 3.3 | M4 | 6.0 |
| 4.0 mm | 4.1 | M5 | 7.0 |
| 4.8 mm | 4.9 | M6 | 9.0 |
| 6.4 mm | 6.5 | M8 | 11.0 |
| — | — | M10 | 13.0 |
| — | — | M12 | 15.0 / 16.0 |
Coatings and finishes
Choose a finish by where the joint will live. Salt-spray hours are typical values to red rust and depend on the exact specification.
| Finish | Thickness | Salt spray (typical) | Best for | Watch out for |
|---|---|---|---|---|
| Zinc plated, clear / blue | 5–8 µm | 72–120 h | Indoors, dry outdoor | Rusts quickly near the sea |
| Zinc plated, yellow | 8 µm | 96–200 h | Machinery, electrical panels | Contains passivate colour |
| Zinc-nickel | 8–12 µm | 500–720 h+ | Automotive, under-bonnet | Higher cost |
| Hot-dip galvanised (HDG) | 45–85 µm | Decades outdoors | Structures, towers, outdoor steel | Nuts are tapped oversize; use HDG nuts |
| Zinc flake (Geomet, Delta-Protekt) | 8–12 µm | 480–1000 h | 10.9 / 12.9 bolts, wind, automotive | No hydrogen embrittlement risk |
| Black oxide + oil | ~1 µm | Very low | Socket cap screws indoors, tooling | Not for outdoor use |
| Phosphate + oil | 5–15 µm | Low | Lubricated assembly, paint base | Store dry |
| Stainless, passivated | — | Inherent | Food, marine, chemical | Galling; isolate from aluminium in wet areas |
Electroplating 10.9 and 12.9 bolts needs baking to avoid hydrogen embrittlement. Zinc flake coatings avoid the risk.
Galvanic corrosion: which fastener in which metal?
In wet or salty conditions, two different metals form a battery and the less noble one corrodes. The fastener should be the more noble metal, because it is small next to the large part.
| Fastener ↓ / Part → | Carbon steel | Galvanised steel | Stainless steel | Aluminium | Copper / brass |
|---|---|---|---|---|---|
| Zinc-plated steel | ✓ | ✓ | ✕ | ! | ✕ |
| Stainless A2 / A4 | ✓ | ! | ✓ | ! | ✓ |
| Aluminium | ✕ | ! | ✕ | ✓ | ✕ |
| Brass / copper | ! | ✕ | ✓ | ✕ | ✓ |
| Titanium | ✓ | ! | ✓ | ! | ✓ |
✓ Good ! Use with care or isolate (nylon washer, sealant) ✕ Avoid in wet conditions
Panel hardware selector: lock, hinge, material and seal
Pick the kind of enclosure or door. The selector suggests the lock, hinge, material, gasket and protection rating that usually suit it, with links to the matching catalogue groups.
A starting point only. Check the grip range, load rating and cut-out of each series on its catalogue page, or ask our team to match parts to your drawing.
IP and IK rating decoder (IEC 60529 / IEC 62262)
Choose the two IP digits and the IK code to see exactly what protection an enclosure, lock or gasket offers, with the nearest NEMA type.
IP ratings cover the complete, correctly closed enclosure. A lock, gland or vent fitted later must have at least the same rating, and gaskets must be compressed as designed.
Panel locks: cam, swing handle and rod control
How to choose a turning tongue (cam) lock, a swing handle lock or a multi-point rod control system, and which insert or key suits each application.
| Lock type | How it works | Best for | Catalogue |
|---|---|---|---|
| Turning tongue (cam) lock | Quarter-turn: a cam (tongue) behind the door swings over the frame. Compression versions pull the door tight onto the gasket. | Small and medium doors, covers, meter boxes, control panels | Cam locks, 174 series |
| Swing handle (plane) lock | A flush handle swings out and turns to release. Often padlockable and key-locking; many drive a rod system. | Electrical, telecom and outdoor cabinets, larger doors | Swing handle locks, 118 series |
| Rod control (multi-point) lock | The handle moves rods that latch the door at top and bottom as well as at the handle. | Tall doors where one latch point would let the door bow and the seal leak | Rod control, 60 series |
| Draw latch / toggle catch | An over-centre lever pulls two parts together under tension. | Covers, cases, lids and machine panels | Hasps & latches, 42 series |
Choosing a cam lock
- Grip range: the door (panel) thickness the lock body clamps. Choose a series whose grip covers your sheet thickness, including any powder coat.
- Cam length and offset: the cam must reach past the frame lip. Straight cams suit flush frames; cranked (offset) cams step forward or back to meet a recessed frame.
- Rotation: 90° (quarter-turn) is standard; 180° and stop-free versions are available for special frames.
- Compression: a compression cam moves the door inwards by a few millimetres as it turns, which is what keeps an IP54–IP66 gasket sealed.
- Cut-out: most locks fit a D-cut or double-D cut-out, which stops the body turning. Take the exact size from the series page.
Insert and key types
| Insert | Typical sizes | Where it is used |
|---|---|---|
| Square | 7 mm, 8 mm | Electrical panels, distribution boards, machine cabinets |
| Triangle | 7 mm, 8 mm, 9 mm | Utility, railway and street cabinets |
| Double-bit | 3 mm, 5 mm | Switchgear and control cabinets, common in Europe |
| Slot / screwdriver | – | Low-security covers and service hatches |
| Hexagon | various | Machine guards where a tool is required by safety rules |
| Key cylinder | keyed alike, keyed different, master key | Restricted access, outdoor and public areas |
| Knob, wing or lever | – | Frequent access without a tool |
| Padlockable handle | shackle hole | Lock-out / tag-out and site security |
Lock cylinders, keys, cams, rods, guides and dust caps are listed under Accessories.
Hinges: types, opening angle and how many to fit
Concealed, flat-mount, lift-off, detachable and damping hinges compared, with a rule of thumb for how many hinges a door needs.
| Hinge type | Features | Use it when |
|---|---|---|
| Concealed (internal) | Hidden when the door is closed; cannot be removed from outside | Security and a clean exterior matter: electrical and outdoor cabinets |
| Flat-mount / surface | Bolts or rivets onto the face of door and frame | Simple doors, retrofits, machine covers |
| Lift-off | Door lifts off its pin when open | Doors need to come off for wiring or maintenance |
| Detachable / clip-pin | Pin or clip releases without tools | Fast door removal and fitting on assembly lines |
| Damping / friction | Controls closing speed or holds the door at any angle | Lids, HMI covers, heavy or overhead doors |
| 120° / 180° opening | Wide opening for full access | Cabinets in rows, or where equipment slides out |
| Stainless steel | SS 304 / 316, no coating to chip | Outdoor, coastal, food and pharma equipment |
| Door height | Usual number of hinges |
|---|---|
| Up to about 1,000 mm | 2 |
| About 1,000 to 2,000 mm | 3 |
| Over about 2,000 mm, or heavy doors | 4 or more |
A rule of thumb used in the panel industry. Check the door weight against the load rating of the hinge series, and place hinges near the top and bottom of the door. See all 159 hinge series.
Materials and finishes for locks, hinges and handles
Zinc alloy, stainless steel, polyamide and steel compared: strength, corrosion resistance and where each belongs.
| Material | Typical finishes | Properties | Best for |
|---|---|---|---|
| Zinc alloy (die-cast) | Chrome plated, black powder coated or painted | Strong, precise castings for complex shapes; good indoor corrosion resistance | Most locks, handles and hinges indoors and in sheltered outdoor use |
| Stainless steel 304 | Natural, satin or brushed | No coating to wear off; good corrosion resistance | Outdoor cabinets, general industry |
| Stainless steel 316 | Natural, satin or brushed | Molybdenum adds resistance to salt and chemicals | Coastal, marine, chemical, food and wash-down |
| Polyamide (PA6 / PA66, often glass-filled) | Black, grey, UV-stabilised | Light, insulating, does not corrode; check the flame rating (UL 94) where required | Plastic enclosures, telecom, low-weight doors |
| Steel, zinc plated | Clear or black zinc | Strong and economical | Internal parts: cams, rods, brackets |
| Aluminium | Anodised or powder coated | Light and corrosion resistant | Handles and profiles |
For enclosures near the sea or in chemical plants, choose stainless 316 hardware and avoid mixing metals; see galvanic corrosion.
Gaskets and sealing strips
Which gasket material to use for the temperature and environment, and how much to compress it to keep the IP rating.
| Material | Typical service temperature | Strengths | Typical use |
|---|---|---|---|
| EPDM (solid or sponge) | about −40 to +120 °C | Excellent weather, ozone and UV resistance | Outdoor enclosures, doors and windows |
| Silicone | about −60 to +200 °C | Wide temperature range; food-grade versions | Hot equipment, food and pharma |
| Neoprene (CR) | about −30 to +100 °C | Moderate oil resistance, flame retardant grades | Industrial and transport panels |
| Polyurethane, foamed in place (PU) | about −40 to +80 °C | Applied by machine as a continuous bead | Series-produced enclosures, IP54–IP66 |
| PVC | about −20 to +60 °C | Economical | Indoor cabinets, dust seals |
- Compression: sponge gaskets usually seal at about 25–40% compression. Too little leaks; too much takes a permanent set.
- Continuous ring: joins and corners are the usual leak points; fit the strip in one length with a sealed joint at the bottom.
- Compression locks: use compression cam or swing handle locks, and enough latch points, so the gasket is pressed evenly all round.
Self-adhesive sponge gaskets, edge protection with steel core and window rubber are listed under Sealing strips & gaskets.
Enclosure standards quick reference
The standards that apply to electrical enclosures and their hardware, with the IP to NEMA comparison buyers ask for most.
| Standard | Covers |
|---|---|
| IEC 60529 | IP code: protection against solids and water |
| IEC 62262 | IK code: protection against mechanical impact |
| IEC 62208 | Empty enclosures for low-voltage switchgear and controlgear |
| IEC 61439 | Low-voltage switchgear and controlgear assemblies (panel builders) |
| NEMA 250 / UL 50, UL 50E | North American enclosure types and tests |
| IEC 60715 | DIN mounting rails: 35 × 7.5 mm and 35 × 15 mm top-hat rail |
| IEC 60297 / EIA-310 | 19-inch racks: 1U = 44.45 mm |
| EN 62444 | Cable glands; metric threads M12 to M63 (PG threads are the older standard) |
| RAL 7035 | The usual light grey colour for electrical enclosures |
| NEMA type | Nearest IP | Typical location |
|---|---|---|
| 1 | IP10 | Indoor, general purpose |
| 2 | IP11 | Indoor, dripping water |
| 3R | IP14 | Outdoor, rain |
| 3 / 3S | IP54 | Outdoor, rain, sleet and windblown dust |
| 4 / 4X | IP56 (IP66 often specified) | Hose-down; 4X also corrosion resistant |
| 5 | IP52 | Indoor, settling dust |
| 6 / 6P | IP67 | Temporary / prolonged submersion |
| 12 / 12K | IP52 | Indoor, dust and dripping oil |
| 13 | IP54 | Indoor, dust, oil and coolant spray |
NEMA types include tests that IP codes do not (corrosion, icing, oil), so a NEMA type can be converted to an IP code but not the other way round.
This page is a quick guide. For design and inspection, always check the current edition of the standard named on your drawing. Ask our team if you are unsure which grade, finish or size you need.
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