304 (A2) · 316 (A4) · A4-80 · Brass · Mild Steel · Nylon
Machine Screw
Machine screws with a uniform metric thread for tapped holes and nuts, pan, countersunk, cheese, round and mushroom heads in Phillips, slotted, Pozi and Torx drive.
About the Machine Screw
Machine screws have a fine, even thread for tapped holes, nuts and inserts, for fixing switchgear, electrical fittings, hinges, brackets, panels and vehicle accessories. They come with pan, countersunk, cheese, round, mushroom and fillister heads and Phillips, Pozi, slotted or Torx drives, in zinc plated or black steel, 304 and 316 stainless, brass and nylon, from M2 to M12 and in BSW, UNC and UNF. Choose the head, material, size and length above; the guide below covers head and drive types, materials and thread rolling screws.
Also called metal thread screws or machine thread screws.
Features
- Uniform metric machine thread
- Pan, countersunk, cheese, round, mushroom and fillister heads
- Phillips, slotted, Pozi, Torx and combi drives
- Thread-rolling and Taptite options
- Zinc-plated and stainless finishes
Applications
- Tapped holes and threaded inserts
- Electronics and electrical components
- Machinery and vehicle accessories
- General assembly
What machine screws are
A machine screw (also called a metal thread screw) has a uniform machine thread and a blunt end. It does not cut its own thread: it screws into a tapped hole, a nut, a rivet nut or another threaded insert, so it can be undone and refitted. Machine screws are made for metal-to-metal fixing, often in pre-tapped holes in electronics and machinery, and can be used with a nut anywhere else.
Compared with a bolt, a machine screw is a smaller, more precise thread with tighter tolerances, and it takes a screwdriver or bit instead of a spanner. Need a screw that cuts its own thread in sheet metal or plastic instead? That is a self tapping screw.
Pan head screws, countersunk and other heads
- Pan head: a raised, flat-topped head with a rounded edge that sits on the surface. The everyday machine screw head, in zinc, black, stainless and brass.
- Countersunk: a flat top that sits flush in a countersunk hole, for a smooth finish. Zinc, stainless, brass and nylon.
- Cheese head: a tall, straight-sided slotted head (DIN 84), in 304 and 316 stainless and nylon.
- Round head: a domed slotted head, in 304 and 316 stainless BSW and in nylon UNC.
- Mushroom head: a low, wide dome, in 304 stainless, metric and BSW.
- Fillister and binder heads: in nylon only (fillister in UNC, binder in M5).
- Thread rolling pan head: a zinc plated Torx drive screw that forms its own thread in a pre-drilled hole in metal (see below).
Phillips, Pozi, slotted or Torx?
- Phillips: the most common drive across our zinc, black and stainless ranges.
- Pozi: gives better torque control and better contact with the bit, so it is less likely to slip or round out. Our zinc plated Pozi pan heads take PZ0 (M2), PZ1 (M2.5 and M3), PZ2 (M4 and M5) and PZ3 (M6).
- Slotted: a straight slot for a flat blade. Near the sea, a slot lets saltwater drain out, where Phillips and hex recesses can hold water and lead to tea staining on stainless.
- Torx: the six-point star on our thread rolling screws: T10 (M3), T20 (M4), T25 (M5) and T30 (M6).
- Phillips/slot combi: zinc plated pan heads in M6 and M8 x 25 that take either a Phillips or a flat blade.
Machine screw sizes: M3, M4, M5, M6 screws and more
A metric machine screw is named by its thread diameter in millimetres and its length: an M4 x 20 is a 4mm thread, 20mm long. Length is measured overall, including the head, on a countersunk screw, and from under the head on pan, cheese, round and mushroom heads. Each metric size has one standard coarse pitch in our range: M2 0.4mm, M2.5 0.45mm, M3 0.5mm, M4 0.7mm, M5 0.8mm, M6 1.0mm, M8 1.25mm, M10 1.5mm and M12 1.75mm. Imperial screws are named by gauge or fraction and threads per inch: a #10-24 UNC has 24 threads per inch.
Match the thread system of the hole or nut you are screwing into: metric, BSW (British Standard Whitworth), UNC (Unified coarse) or UNF (Unified fine). If you are replacing a screw, take one along or measure its diameter and count the threads. The tables list every machine screw we carry, smallest to largest within each range.
Zinc plated and black machine screws
Every zinc plated and zinc black passivate machine screw we carry, all metric coarse thread (size x pitch in mm). Lengths in mm (countersunk overall, other heads from under the head). Sold in packs of 100 to 1,000 depending on the size; the pack shows when you pick a length. Tap a number to show it in the selector above.
| Size | Range | Lengths (mm) |
|---|---|---|
| Zinc plated pan head, Phillips | ||
| M2 x 0.4 | Zinc plated pan head, Phillips | 4, 5, 6, 8, 10, 12, 16, 20 |
| M2.5 x 0.45 | Zinc plated pan head, Phillips | 4, 5, 6, 8, 10, 12, 16, 20, 25 |
| M3 x 0.5 | Zinc plated pan head, Phillips | 4, 6, 8, 10, 12, 16, 20, 25, 30, 35, 40, 50 |
| M4 x 0.7 | Zinc plated pan head, Phillips | 6, 8, 10, 12, 16, 20, 25, 30, 35, 40, 45, 50, 60, 65, 70, 75, 100 |
| M5 x 0.8 | Zinc plated pan head, Phillips | 6, 8, 10, 12, 16, 20, 25, 30, 35, 40, 45, 50, 65, 75, 100 |
| M6 x 1 | Zinc plated pan head, Phillips | 8, 10, 12, 16, 20, 25, 30, 35, 40, 45, 50, 60, 65, 75, 100 |
| M8 x 1.25 | Zinc plated pan head, Phillips | 20, 25, 30, 40, 50 |
| Zinc plated pan head, Pozi | ||
| M2 x 0.4 | Zinc plated pan head, Pozi | 4, 6, 8, 12, 16 |
| M2.5 x 0.45 | Zinc plated pan head, Pozi | 5, 6, 8, 12 |
| M3 x 0.5 | Zinc plated pan head, Pozi | 4, 5, 6, 8, 10, 12, 16 |
| M4 x 0.7 | Zinc plated pan head, Pozi | 4, 5, 6, 8, 10, 12, 16, 20, 25, 30, 35, 40, 60, 65 |
| M5 x 0.8 | Zinc plated pan head, Pozi | 12, 16, 20, 30 |
| M6 x 1 | Zinc plated pan head, Pozi | 8, 16, 20, 25, 35 |
| Zinc plated pan head, Phillips/slot combi | ||
| M6 x 1 | Zinc plated pan head, Phillips/slot combi | 25 |
| M8 x 1.25 | Zinc plated pan head, Phillips/slot combi | 25 |
| Zinc black passivate pan head, Phillips | ||
| M3 x 0.5 | Zinc black passivate pan head, Phillips | 6, 8, 10, 12 |
| M4 x 0.7 | Zinc black passivate pan head, Phillips | 6, 8, 10, 12, 16, 20, 25 |
| M5 x 0.8 | Zinc black passivate pan head, Phillips | 12, 16, 20, 25 |
| M6 x 1 | Zinc black passivate pan head, Phillips | 12, 16, 20, 25, 30 |
| Zinc plated countersunk, Phillips | ||
| M2 x 0.4 | Zinc plated countersunk, Phillips | 5, 6, 8, 10, 12, 16 |
| M2.5 x 0.45 | Zinc plated countersunk, Phillips | 4, 5, 6, 8, 10, 12, 16, 20, 25 |
| M3 x 0.5 | Zinc plated countersunk, Phillips | 4, 5, 6, 8, 10, 12, 16, 20, 25, 30, 35, 40, 45, 50 |
| M4 x 0.7 | Zinc plated countersunk, Phillips | 6, 8, 10, 12, 16, 20, 25, 30, 35, 40, 45, 50, 65, 75, 100 |
| M5 x 0.8 | Zinc plated countersunk, Phillips | 6, 8, 10, 12, 16, 20, 25, 30, 35, 40, 45, 50, 65, 75 |
| M6 x 1 | Zinc plated countersunk, Phillips | 8, 10, 12, 16, 20, 25, 30, 35, 40, 45, 50, 60, 65, 75 |
| M8 x 1.25 | Zinc plated countersunk, Phillips | 16, 20, 25, 30, 40, 50, 100 |
| Zinc plated thread rolling pan head, Torx (DIN 7500) | ||
| M3 x 0.5 | Zinc plated thread rolling pan head, Torx (DIN 7500) | 6, 8, 10, 12, 14 |
| M4 x 0.7 | Zinc plated thread rolling pan head, Torx (DIN 7500) | 8, 10, 12, 16, 20 |
| M5 x 0.8 | Zinc plated thread rolling pan head, Torx (DIN 7500) | 10, 12, 16, 20 |
| M6 x 1 | Zinc plated thread rolling pan head, Torx (DIN 7500) | 10, 12, 16, 20, 30 |
Stainless steel machine screws (metric)
Every metric 304 and 316 stainless machine screw we carry, plus one BUMAX 88 Taptite screw (BUMAX 88 is a stainless grade Hobson lists as equivalent to class 8.8 tensile strength), metric coarse thread (size x pitch in mm), with the head standard in brackets. Lengths in mm (countersunk overall, other heads from under the head). Sold in packs of 50 to 200 depending on the size; the pack shows when you pick a length. Tap a number to show it in the selector above.
| Size | Range | Lengths (mm) |
|---|---|---|
| 304 stainless pan head, Phillips (DIN 7985) | ||
| M2.5 x 0.45 | 304 stainless pan head, Phillips (DIN 7985) | 5, 6, 8, 10, 12, 16, 20, 25 |
| M3 x 0.5 | 304 stainless pan head, Phillips (DIN 7985) | 6, 8, 10, 12, 16, 20, 25, 30, 35, 40, 50 |
| M4 x 0.7 | 304 stainless pan head, Phillips (DIN 7985) | 6, 8, 10, 12, 16, 20, 25, 30, 35, 40, 50, 60 |
| M5 x 0.8 | 304 stainless pan head, Phillips (DIN 7985) | 8, 10, 12, 16, 20, 25, 30, 35, 40, 50, 65, 75 |
| M6 x 1 | 304 stainless pan head, Phillips (DIN 7985) | 8, 10, 12, 16, 20, 25, 30, 35, 40, 50, 60, 65, 75 |
| M8 x 1.25 | 304 stainless pan head, Phillips (DIN 7985) | 20, 25, 30, 40, 50 |
| 316 stainless pan head, Phillips (DIN 7985) | ||
| M2.5 x 0.45 | 316 stainless pan head, Phillips (DIN 7985) | 12 |
| M3 x 0.5 | 316 stainless pan head, Phillips (DIN 7985) | 6, 8, 10, 12, 16, 20, 25 |
| M4 x 0.7 | 316 stainless pan head, Phillips (DIN 7985) | 6, 8, 10, 12, 16, 20, 25, 30, 50 |
| M5 x 0.8 | 316 stainless pan head, Phillips (DIN 7985) | 10, 12, 16, 20, 25, 30, 40, 50 |
| M6 x 1 | 316 stainless pan head, Phillips (DIN 7985) | 12, 16, 20, 25, 30, 40, 50 |
| 304 stainless countersunk, Phillips (DIN 965) | ||
| M2.5 x 0.45 | 304 stainless countersunk, Phillips (DIN 965) | 5, 6, 8, 10, 12, 16, 20 |
| M3 x 0.5 | 304 stainless countersunk, Phillips (DIN 965) | 5, 6, 8, 10, 12, 16, 20, 25, 30, 40, 50 |
| M4 x 0.7 | 304 stainless countersunk, Phillips (DIN 965) | 6, 8, 10, 12, 16, 20, 25, 30, 35, 40, 50 |
| M5 x 0.8 | 304 stainless countersunk, Phillips (DIN 965) | 8, 10, 12, 16, 20, 25, 30, 35, 40, 50, 65, 75 |
| M6 x 1 | 304 stainless countersunk, Phillips (DIN 965) | 10, 12, 16, 20, 25, 30, 35, 40, 45, 50, 60, 65, 75 |
| M8 x 1.25 | 304 stainless countersunk, Phillips (DIN 965) | 16, 20, 25, 30, 40, 50 |
| 316 stainless countersunk, Phillips (DIN 965) | ||
| M2 x 0.4 | 316 stainless countersunk, Phillips (DIN 965) | 5, 6, 8, 10, 12, 16, 20 |
| M2.5 x 0.45 | 316 stainless countersunk, Phillips (DIN 965) | 4, 5, 6, 8, 10, 12, 16, 20 |
| M3 x 0.5 | 316 stainless countersunk, Phillips (DIN 965) | 6, 8, 10, 12, 16, 20, 25 |
| M4 x 0.7 | 316 stainless countersunk, Phillips (DIN 965) | 8, 10, 12, 16, 20, 25, 30, 40 |
| M5 x 0.8 | 316 stainless countersunk, Phillips (DIN 965) | 10, 12, 16, 20, 25, 30, 40, 50 |
| M6 x 1 | 316 stainless countersunk, Phillips (DIN 965) | 12, 16, 20, 25, 30, 35, 40, 50 |
| M8 x 1.25 | 316 stainless countersunk, Phillips (DIN 965) | 16, 20, 25, 30, 40, 50, 60 |
| M10 x 1.5 | 316 stainless countersunk, Phillips (DIN 965) | 25, 30 |
| 304 stainless countersunk, slotted (DIN 963) | ||
| M3 x 0.5 | 304 stainless countersunk, slotted (DIN 963) | 8, 10, 12, 16, 20, 25, 30, 40 |
| M4 x 0.7 | 304 stainless countersunk, slotted (DIN 963) | 8, 10, 12, 16, 20, 25, 30, 40, 50 |
| M5 x 0.8 | 304 stainless countersunk, slotted (DIN 963) | 10, 12, 16, 20, 25, 30, 35, 40, 45, 50, 60, 65, 70 |
| M6 x 1 | 304 stainless countersunk, slotted (DIN 963) | 10, 12, 16, 20, 25, 30, 35, 40, 45, 50, 60, 65, 70 |
| 316 stainless countersunk, slotted (DIN 963) | ||
| M3 x 0.5 | 316 stainless countersunk, slotted (DIN 963) | 8, 10, 12, 16, 20, 25 |
| M4 x 0.7 | 316 stainless countersunk, slotted (DIN 963) | 8, 10, 12, 16, 20, 25, 30, 40, 50 |
| M5 x 0.8 | 316 stainless countersunk, slotted (DIN 963) | 10, 12, 16, 20, 25, 30, 40, 45, 50, 60, 65, 70 |
| M6 x 1 | 316 stainless countersunk, slotted (DIN 963) | 10, 12, 16, 20, 25, 30, 35, 40, 45, 50, 60, 65, 70 |
| M8 x 1.25 | 316 stainless countersunk, slotted (DIN 963) | 12, 16, 20, 25, 30, 40, 50, 60 |
| 304 stainless cheese head, slotted (DIN 84) | ||
| M3 x 0.5 | 304 stainless cheese head, slotted (DIN 84) | 6, 8, 10, 12, 20, 25, 30, 40, 50 |
| M4 x 0.7 | 304 stainless cheese head, slotted (DIN 84) | 6, 8, 10, 12, 16, 20, 25, 30, 40, 50 |
| M5 x 0.8 | 304 stainless cheese head, slotted (DIN 84) | 6, 8, 10, 12, 16, 20, 25, 30, 35, 40, 50, 60, 70 |
| M6 x 1 | 304 stainless cheese head, slotted (DIN 84) | 10, 12, 16, 20, 25, 30, 35, 40, 50, 60, 70 |
| 316 stainless cheese head, slotted (DIN 84) | ||
| M3 x 0.5 | 316 stainless cheese head, slotted (DIN 84) | 6, 8, 10, 12, 16, 20, 25, 35 |
| M4 x 0.7 | 316 stainless cheese head, slotted (DIN 84) | 6, 8, 10, 12, 16, 20, 25, 30, 40, 50 |
| M5 x 0.8 | 316 stainless cheese head, slotted (DIN 84) | 10, 12, 16, 20, 25, 30, 40, 50, 60, 70 |
| M6 x 1 | 316 stainless cheese head, slotted (DIN 84) | 10, 12, 16, 20, 25, 30, 35, 40, 50, 60, 70 |
| 304 stainless mushroom head, Phillips (AS 1427) | ||
| M5 x 0.8 | 304 stainless mushroom head, Phillips (AS 1427) | 20, 25 |
| M6 x 1 | 304 stainless mushroom head, Phillips (AS 1427) | 25, 30, 40 |
| BUMAX 88 stainless Taptite pan head, Torx (ISO 14583) | ||
| M8 x 1.25 | BUMAX 88 stainless Taptite pan head, Torx (ISO 14583) | 40 |
Brass and nylon machine screws (metric)
Every metric brass and nylon machine screw we carry, metric coarse thread (size x pitch in mm). Lengths in mm (countersunk overall, other heads from under the head). Sold in packs of 25 to 200 depending on the size; the pack shows when you pick a length. Tap a number to show it in the selector above.
| Size | Range | Lengths (mm) |
|---|---|---|
| Brass pan head, slotted (AS 1427) | ||
| M4 x 0.7 | Brass pan head, slotted (AS 1427) | 10, 12, 16, 20, 25, 30, 40, 50, 65 |
| M5 x 0.8 | Brass pan head, slotted (AS 1427) | 6, 8, 10, 12, 16, 20, 25, 30, 40, 50 |
| Brass countersunk, slotted (AS 1427) | ||
| M4 x 0.7 | Brass countersunk, slotted (AS 1427) | 6, 8, 10, 12, 16, 20, 25, 30, 40, 50 |
| M5 x 0.8 | Brass countersunk, slotted (AS 1427) | 10, 12, 16, 20, 25, 30, 40, 50 |
| M6 x 1 | Brass countersunk, slotted (AS 1427) | 10, 12, 16, 20, 25, 30, 40, 50 |
| Nylon cheese head, slotted (DIN 84) | ||
| M2.5 x 0.45 | Nylon cheese head, slotted (DIN 84) | 5, 8, 10, 12, 16, 20, 25 |
| M3 x 0.5 | Nylon cheese head, slotted (DIN 84) | 6, 8, 10, 12, 16, 20, 25, 35 |
| M4 x 0.7 | Nylon cheese head, slotted (DIN 84) | 6, 8, 10, 12, 16, 20, 25, 30, 40, 50 |
| M5 x 0.8 | Nylon cheese head, slotted (DIN 84) | 10, 12, 16, 20, 25, 30, 40, 50, 60, 70 |
| M6 x 1 | Nylon cheese head, slotted (DIN 84) | 10, 12, 16, 20, 25, 30, 35, 40, 50, 60, 70 |
| M8 x 1.25 | Nylon cheese head, slotted (DIN 84) | 12, 16, 20, 25, 30, 35, 40, 50, 60, 70, 80 |
| M10 x 1.5 | Nylon cheese head, slotted (DIN 84) | 30, 35 |
| Nylon countersunk, slotted (DIN 963) | ||
| M3 x 0.5 | Nylon countersunk, slotted (DIN 963) | 6, 8, 10, 12, 16, 20, 25, 30 |
| M4 x 0.7 | Nylon countersunk, slotted (DIN 963) | 6, 8, 10, 12, 16, 20, 25, 30, 40 |
| M5 x 0.8 | Nylon countersunk, slotted (DIN 963) | 10, 12, 16, 20, 25, 30, 35, 40, 45, 50, 65 |
| M6 x 1 | Nylon countersunk, slotted (DIN 963) | 10, 12, 15, 20, 25, 30, 35, 40, 45, 50, 65 |
| M8 x 1.25 | Nylon countersunk, slotted (DIN 963) | 10, 12, 15, 20, 25, 30, 35, 40, 45, 50, 65 |
| M10 x 1.5 | Nylon countersunk, slotted (DIN 963) | 25, 30, 35, 40, 45, 50 |
| M12 x 1.75 | Nylon countersunk, slotted (DIN 963) | 65 |
| Nylon binder head, Phillips (DIN 7985) | ||
| M5 x 0.8 | Nylon binder head, Phillips (DIN 7985) | 40 |
Imperial machine screws: BSW, UNC and UNF
Every imperial machine screw we carry, shown as size and threads per inch. Lengths in inches. Sold in packs of 50, 100 or 200 depending on the size; the pack shows when you pick a length. Tap a number to show it in the selector above.
| Size | Range | Lengths (inch) |
|---|---|---|
| 304 stainless pan head, Phillips | ||
| 1/8-40 BSW | 304 stainless pan head, Phillips | 1/2, 3/4, 1 |
| 3/16-24 BSW | 304 stainless pan head, Phillips | 1/4, 3/8, 1/2, 5/8, 3/4, 1, 1-1/4, 1-1/2, 2, 2-1/2, 3 |
| 1/4-20 BSW | 304 stainless pan head, Phillips | 3/8, 1/2, 5/8, 3/4, 1, 1-1/4, 1-1/2, 2, 2-1/2, 3, 3-1/2, 4 |
| 5/16-18 BSW | 304 stainless pan head, Phillips | 3/4, 1, 1-1/2, 1-3/4, 2, 2-1/2, 3 |
| #4-40 UNC | 304 stainless pan head, Phillips | 3/16, 1/4, 5/16, 3/8, 1/2, 5/8, 3/4, 1 |
| #6-32 UNC | 304 stainless pan head, Phillips | 1/4, 5/16, 3/8, 1/2, 5/8, 3/4, 1, 1-1/4, 1-1/2, 2 |
| #8-32 UNC | 304 stainless pan head, Phillips | 1/4, 3/8, 1/2, 5/8, 3/4, 1, 1-1/4, 1-1/2, 1-3/4, 2 |
| #10-32 UNF | 304 stainless pan head, Phillips | 3/8, 1/2, 3/4, 1, 1-1/4, 1-1/2, 2 |
| 316 stainless pan head, Phillips | ||
| 3/16-24 BSW | 316 stainless pan head, Phillips | 1/2, 3/4, 1, 1-1/4, 1-1/2, 2, 2-1/2, 3 |
| 1/4-20 BSW | 316 stainless pan head, Phillips | 3/4, 1, 1-1/4, 1-1/2, 2, 3 |
| 304 stainless countersunk, Phillips | ||
| 1/8-40 BSW | 304 stainless countersunk, Phillips | 1/4 |
| 5/32-32 BSW | 304 stainless countersunk, Phillips | 1/4, 3/8, 1/2, 1 |
| 3/16-24 BSW | 304 stainless countersunk, Phillips | 1/4, 3/8, 1/2, 5/8, 3/4, 1, 1-1/4, 1-1/2, 1-3/4, 2, 2-1/2, 3 |
| 1/4-20 BSW | 304 stainless countersunk, Phillips | 1/2, 5/8, 3/4, 1, 1-1/4, 1-1/2, 1-3/4, 2, 2-1/2, 3, 4 |
| 5/16-18 BSW | 304 stainless countersunk, Phillips | 3/4, 1, 1-1/4, 1-1/2, 2, 2-1/2, 3 |
| #2-56 UNC | 304 stainless countersunk, Phillips | 1/4, 3/8, 1/2 |
| #4-40 UNC | 304 stainless countersunk, Phillips | 1/4, 5/16, 3/8, 1/2, 5/8, 3/4, 1 |
| #6-32 UNC | 304 stainless countersunk, Phillips | 1/4, 5/16, 3/8, 1/2, 5/8, 3/4, 1, 1-1/4, 1-1/2, 2 |
| #8-32 UNC | 304 stainless countersunk, Phillips | 1/4, 3/8, 1/2, 5/8, 3/4, 1, 1-1/4, 1-1/2, 2 |
| #12-24 UNC | 304 stainless countersunk, Phillips | 1/2 |
| #10-32 UNF | 304 stainless countersunk, Phillips | 3/8, 1/2, 5/8, 3/4, 1, 1-1/4, 1-1/2, 2 |
| 316 stainless countersunk, Phillips | ||
| 3/16-24 BSW | 316 stainless countersunk, Phillips | 3/8, 1/2, 3/4, 1, 1-1/4, 1-1/2, 2, 2-1/2, 3 |
| 1/4-20 BSW | 316 stainless countersunk, Phillips | 3/4, 1, 1-1/4, 1-1/2, 2 |
| 304 stainless round head, slotted | ||
| 1/8-40 BSW | 304 stainless round head, slotted | 1/4, 3/8, 1/2, 5/8, 3/4, 1, 1-1/4, 1-1/2, 2 |
| 5/32-32 BSW | 304 stainless round head, slotted | 1/4, 3/8, 1/2, 5/8, 3/4, 1, 1-1/4, 1-1/2, 2 |
| 3/16-24 BSW | 304 stainless round head, slotted | 1/4, 3/8, 1/2, 5/8, 3/4, 1, 1-1/4, 1-1/2, 1-3/4, 2, 2-1/2, 3 |
| 1/4-20 BSW | 304 stainless round head, slotted | 3/8, 1/2, 5/8, 3/4, 1, 1-1/4, 1-1/2, 1-3/4, 2, 2-1/4, 2-1/2, 3 |
| 316 stainless round head, slotted | ||
| 3/16-24 BSW | 316 stainless round head, slotted | 1/4, 3/8, 1/2, 5/8, 3/4, 1, 1-1/4, 1-3/4, 2, 2-1/2, 3 |
| 1/4-20 BSW | 316 stainless round head, slotted | 1/2, 5/8, 3/4, 1, 1-1/4, 1-1/2, 2, 2-1/2, 3 |
| 304 stainless mushroom head, Phillips | ||
| 3/16-24 BSW | 304 stainless mushroom head, Phillips | 1/2, 5/8, 3/4, 1, 1-1/4, 1-1/2 |
| 1/4-20 BSW | 304 stainless mushroom head, Phillips | 1/2, 3/4, 1 |
| Nylon countersunk, slotted | ||
| #10-24 UNC | Nylon countersunk, slotted | 1/2, 3/4, 1 |
| 1/4-20 UNC | Nylon countersunk, slotted | 1/2, 5/8, 3/4, 1, 1-1/4, 1-1/2, 1-3/4, 2, 2-1/2 |
| Nylon fillister head, slotted | ||
| #10-24 UNC | Nylon fillister head, slotted | 3/8, 1/2, 5/8, 3/4, 1, 1-1/4, 1-1/2, 2 |
| 1/4-20 UNC | Nylon fillister head, slotted | 1/2, 5/8, 3/4, 1, 1-1/2, 2 |
| Nylon round head, slotted | ||
| #10-24 UNC | Nylon round head, slotted | 3/8, 1/2, 5/8, 3/4, 1 |
| 1/4-20 UNC | Nylon round head, slotted | 1/2, 3/4, 1 |
Zinc, stainless, brass or nylon screws?
- Zinc plated steel: electroplated with zinc (about 5 microns) and passivated. Low corrosion resistance: for indoor and non-corrosive conditions.
- Zinc black passivate: zinc plated pan head screws with a black finish, M3 to M6.
- 304 (A2) and 316 (A4) stainless: corrosion resistant right through, with no coating to wear off. 316 adds 2 to 3% molybdenum, the change that was made so stainless would hold up by the sea. Neither is made for sitting in seawater: seawater has about 20 times the chloride that 316 can withstand.
- Brass: an alloy of copper and zinc, valued for its workability, corrosion resistance, conductivity and appearance. Non-magnetic and low friction. Used in electrical and plumbing fittings, hinges, furniture and marine work.
- Nylon (polyamide): absorbs shock and vibration, protects surfaces and gives good electrical insulation. Used where a metal screw would mark a surface or conduct.
Thread rolling screws for metal
Our zinc plated thread rolling screws (DIN 7500, Torx drive, M3 to M6) have a trilobular thread that forms its own thread in a pre-drilled hole in metal. They do away with tapping, and with the washers, nuts and locking compounds a normal machine screw would need. The formed thread gives deep engagement and prevailing torque that resists loosening from vibration. Used in metal framing, automotive work and punched and cast parts. Sold in packs of 1,000.
Recommended hole sizes from the maker's data sheet: M4 3.65 to 3.7mm in steel, 3.7mm in aluminium; M5 4.6 to 4.65mm in steel, 4.65mm in aluminium; M6 5.5 to 5.55mm in steel, 5.65mm in aluminium. For M3, Hobson lists 2.75mm in aluminium.
Fitting machine screws
- Match the thread: metric, BSW, UNC or UNF, and the size of the tapped hole, nut or insert.
- Choose a length that engages the full thread of the nut or tapped hole without bottoming out.
- Pick the head for the finish you want: countersunk for flush, pan or cheese to sit on the surface.
- Use the right bit size so the drive does not cam out or round.
- For stainless screws, drive at a slower speed and lubricate the thread with a molybdenum disulphide based lubricant, so the thread does not gall (seize). Mixing grades (a 316 screw in a 304 nut) also helps.
- Tighten until snug. Small screws strip easily, so do not overtighten.
Machine screws in Adelaide
Allmat supplies machine screws, nuts and washers to fabricators, electricians, maintenance fitters and trade across Adelaide and South Australia. Add the screws to a quote with the rest of your list, and we will price the lot.
Machine screws for fabrication, electrical and repairs
Metric and imperial machine screws in zinc, stainless, brass and nylon are available to order from Allmat for fabricators, electricians, maintenance fitters, cabinet makers and trade across Adelaide and South Australia. Order through Allmat, we pick and pack it, then click and collect from the Allmat yard or have it delivered to site.
Goes with
Questions
What is a machine screw?
A screw with a uniform machine thread and a blunt end that screws into a tapped hole, a nut or a threaded insert. It does not cut its own thread, so it can be undone and refitted.
What is the difference between a machine screw and a bolt?
Machine screws are smaller, with a more precise thread and tighter tolerances, and are driven with a screwdriver or bit. Bolts are larger and usually tightened with a spanner on a hex head.
What does M4 mean on a screw?
M4 is a metric thread 4mm in diameter. Our M4 screws have the standard 0.7mm pitch. The number after it is the length in mm, so M4 x 20 is 20mm long. In the same way, M3 screws have a 3mm thread and M5 screws a 5mm thread. M3 bolts and M4 bolts are these same parts: at sizes this small, what people call a bolt is a machine screw, used with a nut or in a tapped hole.
What are pan head screws used for?
Pan heads sit on the surface with a low, rounded head, so they suit fixing metal parts, electrical components, machinery, and vehicle accessories such as licence plates and lights. Use countersunk screws where the head must sit flush.
Do you have stainless machine screws?
Yes. 304 and 316 stainless in pan, countersunk, cheese and mushroom heads, metric M2 to M10, plus 304 in UNC and UNF and 304 and 316 in BSW.
Do you have nylon screws?
Yes. Nylon cheese head and countersunk machine screws from M2.5 to M12, a binder head in M5, and UNC countersunk, fillister and round heads in #10 and 1/4 inch.
Phillips or slotted stainless screws near the sea?
Slotted drives let saltwater drain out. Phillips and hex recesses can hold water, which leads to tea staining on stainless. Wash salt off stainless fittings regularly either way.
Where can I buy machine screws in Adelaide?
Order through Allmat. Order ahead by phone on 1300 03 03 63 or send your list for a quote, then click and collect from 25 Kapara Road, Gillman, or have them delivered to site.
Machine Screw: sizes and finishes we supply
1,063 lines by type and finish. Pick one above for its product code and pack sizes.
| Head | Finish | Sizes | Lengths | Lines |
|---|---|---|---|---|
| Pan | Zinc Plated | M2, M2.5, M3, M4, M5, M6, M8 | 4 to 100 (20 lengths) | 141 |
| Countersunk | 304 Stainless | M2.5, M3, M4, M5, M6, M8 | 5 to 75 (17 lengths) | 103 |
| Countersunk | 316 Stainless | M2, M2.5, M3, M4, M5, M6, M8, M10 | 4 to 70 (17 lengths) | 103 |
| Countersunk | Zinc Plated | M2, M2.5, M3, M4, M5, M6, M8 | 4 to 100 (18 lengths) | 79 |
| Countersunk | 304 Stainless | 1/8, 5/32, 3/16, 1/4, 5/16, #2, #4, #6, #8, #10, #12 | 1/4 to 4 inch (14 lengths) | 73 |
| Pan | 304 Stainless | 1/8, 3/16, 1/4, 5/16, #4, #6, #8, #10 | 3/16 to 4 inch (16 lengths) | 68 |
| Pan | 304 Stainless | M2.5, M3, M4, M5, M6, M8 | 5 to 75 (15 lengths) | 61 |
| Cheese | Nylon Natural | M2.5, M3, M4, M5, M6, M8, M10 | 5 to 80 (15 lengths) | 59 |
| Countersunk | Nylon Natural | M3, M4, M5, M6, M8, M10, M12 | 6 to 65 (14 lengths) | 57 |
| Cheese | 304 Stainless | M3, M4, M5, M6 | 6 to 70 (13 lengths) | 43 |
| Round | 304 Stainless | 1/8, 5/32, 3/16, 1/4 | 1/4 to 3 inch (13 lengths) | 42 |
| Cheese | 316 Stainless | M3, M4, M5, M6 | 6 to 70 (13 lengths) | 39 |
| Pan | 316 Stainless | M2.5, M3, M4, M5, M6 | 6 to 50 (10 lengths) | 32 |
| Countersunk | Brass | M4, M5, M6 | 6 to 50 (10 lengths) | 26 |
| Pan | Zinc Black Passivate | M3, M4, M5, M6 | 6, 8, 10, 12, 16, 20, 25, 30 | 20 |
| Round | 316 Stainless | 3/16, 1/4 | 1/4 to 3 inch (12 lengths) | 20 |
| Pan | Brass | M4, M5 | 6 to 65 (11 lengths) | 19 |
| Countersunk | 316 Stainless | 3/16, 1/4 | 3/8 to 3 inch (9 lengths) | 14 |
| Pan | 316 Stainless | 3/16, 1/4 | 1/2, 3/4, 1, 1-1/4, 1-1/2, 2, 2-1/2, 3 inch | 14 |
| Fillister | Nylon Natural | 1/4, #10 | 3/8, 1/2, 5/8, 3/4, 1, 1-1/4, 1-1/2, 2 inch | 14 |
| Countersunk | Nylon Natural | 1/4, #10 | 1/2 to 2-1/2 inch (9 lengths) | 12 |
| Mushroom | 304 Stainless | 3/16, 1/4 | 1/2, 5/8, 3/4, 1, 1-1/4, 1-1/2 inch | 9 |
| Round | Nylon Natural | 1/4, #10 | 3/8, 1/2, 5/8, 3/4, 1 inch | 8 |
| Mushroom | 304 Stainless | M5, M6 | 20, 25, 30, 40 | 5 |
| Fillister | Nylon Natural | M5 | 40 | 1 |
| Pan | BUMAX 88 | M8 | 40 | 1 |
Data sheets and documents
The documents for the product you choose are listed with the selector above. Here is every Machine Screw document from Hobson Engineering.
All Machine Screw documents (22)
Data sheets and technical data (8)
Did You Know flyers (6)
Need them in bulk?
Add the sizes you need to your quote, or send us your list and we’ll price the lot and supply it with the rest of your order.
Browse all machine screws