304 (A2) · Alloy Steel · Nylon
Grub Screws (Socket Set Screws)
Grub screws for locking collars, gears, pulleys and knobs onto shafts, with cup, flat and dog points.
About the Grub Screws (Socket Set Screws)
Grub screws, or socket set screws, have no head and lock collars, gears, pulleys, knobs and handles onto a shaft. They come with knurled cup, cup, flat and dog points and a hex socket or slotted drive, in high tensile alloy steel, 304 stainless or nylon, from M2.5 and in UNC and UNF, plus BSP pressure plugs. Choose the point, material and size above; the guide below covers which point to use.
Also called socket set screws or headless screws.
Features
- Cup, knurled cup, dog and flat points
- Hex-key and slotted drive
- High-tensile and stainless
Applications
- Locking gears, pulleys and collars on shafts
- Setting and locating
- Sealing pressure plugs
What grub screws are for
A grub screw (called a set screw in the US) is a fully threaded screw with no head. It screws into a threaded hole in a collar, pulley, gear, knob or handle and presses its point against the shaft inside, locking the part in place. Because it sits flush or below the surface, nothing sticks out to catch.
Which point: cup, knurled cup, flat or dog?
| Point | Standard | Use it for |
|---|---|---|
| Cup | ISO 4029 / DIN 916 | The general purpose point. The cup edge bites into the shaft for a firm hold. |
| Knurled cup | ISO 4029 (metric), ANSI B18.3 (imperial) | A cup point with serrations that resist loosening under vibration. |
| Flat (plain) | DIN 913 (nylon) | Minimal marking, for parts that are adjusted often or that seat on a flat ground on the shaft. |
| Dog | DIN 915 | A plain pin end that locates in a hole or slot drilled in the shaft, for positive location. |
| Slotted, flat point | DIN 551 | Driven with a flat screwdriver, common in nylon. |
Alloy steel, stainless or nylon?
- High tensile alloy steel: the strongest, for machinery, gears and pulleys. Plain black finish, so keep it dry or oiled.
- 304 stainless: corrosion resistant for wet, outdoor and food areas, but not as strong as alloy steel.
- Nylon: will not mark or scratch the shaft, does not rust and does not conduct electricity. For light holding loads.
Fitting grub screws
- Match the thread to the hole: metric (M2.5, M3, M4 and up) or imperial UNC and UNF.
- Choose a length that sits flush or just below the surface when tight.
- Drive hex socket grub screws with the right size hex (Allen) key and slotted ones with a flat screwdriver.
- Where there is vibration, use a knurled cup point, two grub screws, or a thread locking compound.
Grub screws in Adelaide
Allmat supplies grub screws, socket cap screws and machine fasteners to fitters, fabricators and trade across Adelaide and South Australia. Add them to a quote with the rest of your list, and we will price the lot.
Grub screws for maintenance and fabrication
Grub screws and socket screws in metric and imperial sizes are available to order from Allmat for maintenance fitters, fabricators, farmers 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 grub screw called in the US?
A set screw, or socket set screw. In Australia a set screw usually means a hex head screw threaded almost to the head, which is on our hex bolts page; a grub screw is the headless screw on this page.
Which grub screw point should I use?
A cup point for general use, a knurled cup where there is vibration, a flat point where the shaft must not be marked or the part is adjusted often, and a dog point to locate in a drilled hole.
What tool do I need for a grub screw?
A hex (Allen) key that fits the socket for hex socket grub screws, or a flat screwdriver for slotted ones.
How do I stop a grub screw coming loose?
Use a knurled cup point, fit a second grub screw on top of the first, or use a thread locking compound.
Do you have imperial grub screws?
Yes. As well as metric sizes we have UNC and UNF grub screws from #4 up to 1-1/2 inch.
Where can I buy grub 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.
Grub Screws (Socket Set Screws): sizes and finishes we supply
504 lines by type and finish. Pick one above for its product code and pack sizes.
| Head | Finish | Sizes | Lengths | Lines |
|---|---|---|---|---|
| Set / grub | Steel | 3/16, 1/4, 5/16, 3/8, 7/16, 1/2, 5/8, 3/4, 7/8, 1, #4, #5, #6, #8, #10 | 1/8 to 3 inch (17 lengths) | 194 |
| Set / grub | Steel | M1.6, M2, M2.5, M3, M4, M5, M6, M8, M10, M12, M16, M20, M24 | 3 to 60 (16 lengths) | 141 |
| Set / grub | Nylon Natural | M3, M4, M5, M6, M8, M10 | 6 to 70 (14 lengths) | 70 |
| Set / grub | 304 Stainless | M3, M4, M5, M6, M8, M10, M12, M16 | 3 to 50 (14 lengths) | 58 |
| Set / grub | 304 Stainless | 1/4, 5/16, 3/8, 1/2, #4, #5, #6, #8, #10 | 1/8 to 1-1/4 inch (10 lengths) | 28 |
| Pressure plug (BSP) | Alloy Steel | 1/8, 1/4, 3/8, 1/2, 5/8, 3/4, 1, 1-1/4, 1-1/2 | - | 9 |
| Set / grub | Zinc Flake Silver | M8, M16 | 8, 35 | 2 |
| Set / grub | Zinc Plated | M12 | 12 | 1 |
| Set / grub | Nylon Natural | 3/8 | 1 inch | 1 |
Data sheets and documents
The documents for the product you choose are listed with the selector above. Here is every Grub Screws (Socket Set Screws) document from Hobson Engineering.
All Grub Screws (Socket Set Screws) documents (13)
Data sheets and technical data (8)
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.
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