FASTENER GUIDES
Quick reference charts for site engineers, buyers and fabricators. Use them to check a grade, size or finish before you send a quote request.
The grade is stamped on the bolt head. For steel bolts, the first number times 100 is the tensile strength in MPa, and the second number tells you the yield as a share of that. Always pair a bolt with a nut of the matching class. Figures are ISO 898-1 and ISO 3506-1 minimums.
| Grade | Material | Min. tensile (MPa) | Min. yield (MPa) | Matching nut | Typical use |
|---|---|---|---|---|---|
| 4.6 | Low/medium carbon steel | 400 | 240 | Class 5 | Light fixing, timber, general non-structural work |
| 4.8 | Low/medium carbon steel | 420 | 340 | Class 5 | Light fabrication, brackets, everyday hardware |
| 5.8 | Low/medium carbon steel | 520 | 420 | Class 5 | General engineering where 4.8 is not enough |
| 8.8 | Medium carbon steel, quenched and tempered | 800 (up to M16) / 830 (above M16) | 640 / 660 | Class 8 | Structural steel, machinery, vehicles, most construction |
| 10.9 | Alloy steel, quenched and tempered | 1040 | 940 | Class 10 | Heavy machinery, high-load and vibration joints |
| 12.9 | Alloy steel, quenched and tempered | 1220 | 1100 | Class 12 | Tooling, engines, critical high-strength joints |
| A2-70 | Stainless steel (304 type) | 700 | 450 | A2-70 | Outdoor, food and water equipment, humid sites |
| A4-80 | Stainless steel (316 type) | 800 | 600 | A4-80 | Coastal, marine, chemical and salt-exposed sites |
Coarse pitch is the standard unless a drawing says otherwise. Tap drill is for coarse threads; clearance hole is a medium fit. Spanner sizes in brackets are the older DIN sizes you will still find on site.
| Size | Coarse pitch (mm) | Fine pitch (mm) | Tap drill (mm) | Clearance hole (mm) | Spanner (mm) |
|---|---|---|---|---|---|
| M5 | 0.8 | - | 4.2 | 5.5 | 8 |
| M6 | 1.0 | - | 5.0 | 6.6 | 10 |
| M8 | 1.25 | 1.0 | 6.8 | 9 | 13 |
| M10 | 1.5 | 1.25 | 8.5 | 11 | 16 (17) |
| M12 | 1.75 | 1.25 / 1.5 | 10.2 | 13.5 | 18 (19) |
| M14 | 2.0 | 1.5 | 12.0 | 15.5 | 21 (22) |
| M16 | 2.0 | 1.5 | 14.0 | 17.5 | 24 |
| M18 | 2.5 | 1.5 | 15.5 | 20 | 27 |
| M20 | 2.5 | 1.5 | 17.5 | 22 | 30 |
| M22 | 2.5 | 1.5 | 19.5 | 24 | 34 (32) |
| M24 | 3.0 | 2.0 | 21.0 | 26 | 36 |
| M27 | 3.0 | 2.0 | 24.0 | 30 | 41 |
| M30 | 3.5 | 2.0 | 26.5 | 33 | 46 |
Guide tightening values in Nm for coarse-thread steel bolts, plain or zinc plated and lightly oiled. Greased or waxed threads need less torque, and stainless bolts need lower values to avoid galling. Where a drawing or equipment manual gives a figure, use that instead.
| Size | Grade 8.8 (Nm) | Grade 10.9 (Nm) | Grade 12.9 (Nm) |
|---|---|---|---|
| M6 | 10 | 15 | 17 |
| M8 | 25 | 36 | 42 |
| M10 | 49 | 71 | 83 |
| M12 | 85 | 123 | 144 |
| M14 | 135 | 195 | 230 |
| M16 | 210 | 300 | 355 |
| M20 | 410 | 590 | 690 |
| M24 | 710 | 1010 | 1190 |
Start with what you are fixing into. Hollow block and brick need a different anchor from solid concrete. Overhead and safety-critical loads should always be signed off by your engineer.
| Anchor | Fix into | Load | Good for |
|---|---|---|---|
| Wedge anchor | Solid concrete only | Heavy | Steel columns, machinery bases, racking, handrails |
| Drop-in anchor | Solid concrete | Medium | Overhead threaded rod for pipes, ducts and cable trays; removable bolts |
| Expansion bolt (shield anchor) | Concrete, solid brick | Medium | Brackets, gates, frames and equipment on walls |
| Sleeve anchor | Concrete, brick, block | Medium | General fixing where the base material is mixed or unknown |
| Expansion shield | Brick, block, concrete | Medium | Fixing with your own bolt or coach screw |
| Hammer fixing | Brick, block, concrete | Light | Door and window frames, battens, skirting, fast repeat fixing |
| Hook and eye anchors | Concrete, solid brick | Light | Hanging chain, cable, lights and fittings |
| Wall plug | Brick, block, plaster | Light | Screw fixings for shelves, sockets, fittings and signage |
Our catalog uses three finish codes. Pick by where the fastener will live, not by habit. Rust is the most common reason joints fail early in Ghana’s humid and coastal conditions.
SS
YZP
WZP
Got an imperial size from an old drawing or imported machine? Convert it here and we will help you find the closest metric match.
Type a size to convert.
Type a size to convert.
Give us these five things and we can quote without a back-and-forth.
Type
Hex bolt, coach screw, wedge anchor...
Diameter x length
e.g. M12 x 100mm
Grade
e.g. 8.8 or A2-70, if it matters
Finish
SS, WZP or YZP
Quantity
Pieces, boxes or metres
Send a photo or a drawing and our team will identify it for you.
