Polyethylene
Hex Bolt Head Cover (Bolt Cap)
Black UV resistant bolt caps that push over hex bolt and set screw heads for a neat, protected finish on outdoor work.
About the Hex Bolt Head Cover (Bolt Cap)
Bolt caps are black plastic covers that push over a hex bolt or set screw head, to protect it from weather and rust stains and to give a neat, safer finish on decks, fences, playgrounds and outdoor steelwork. They are UV resistant polyethylene, in 11 sizes from M4 to M36 to suit AS 1110 hex bolts, in packs of 50 (M4 to M20), 20 (M24) and 10 (M30 and M36). Choose the size above; the guide below covers matching the cap to the bolt and spanner size, and cap heights.
Also called bolt caps, bolt covers or hex head covers.
Features
- UV-resistant black polyethylene
- Protects bolt head from corrosion and discolouring
- Resists acids, greases and oils
- Sizes M4 to M36
- Suits AS1110 hex bolts and set screws
- Packed 10-50 per size
Applications
- Covering exposed bolt heads on decks, fences and pergolas
- Playground and outdoor structures
- Protecting heads from weather and rust staining
What a bolt cap does
A plug head cover is a domed black cap that fits over the hex head of a bolt or set screw. Hobson makes them from polyethylene, which resists acids, greases and oils, and says the cover protects the bolt head from corrosion and discolouring.
The covers are UV resistant. Hobson defines UV resistance as a material's ability to resist ultraviolet light or sunlight, which makes non-resistant materials fade, discolour, break down and become brittle, so the black caps suit bolt heads that sit out in the sun.
People fit them to give exposed bolt heads a neat, covered finish on fences, gates, pergolas, signs, outdoor furniture frames and machinery.
Bolt cap sizes, spanner sizes and heights
Every size we carry, smallest to largest. Pick the cap with the same thread size as the bolt, then check the spanner size of the head matches. Select a row to open that size.
Thread size, spanner size (across flats, S) and cover height (H) in mm from Hobson's plug head cover sheet. Pack is the minimum order quantity. Tap a number to show it in the selector above.
| Size | Spanner size (AF) | Cover height | Pack | Code |
|---|---|---|---|---|
| M4 | 7mm | 8.8mm | Pack of 50 | PHCPEUM04 |
| M5 | 8mm | 11.0mm | Pack of 50 | PHCPEUM05 |
| M6 | 10mm | 12.8mm | Pack of 50 | PHCPEUM06 |
| M8 | 13mm | 15.8mm | Pack of 50 | PHCPEUM08 |
| M10 | 16mm | 19.0mm | Pack of 50 | PHCPEUM10 |
| M12 | 18mm | 20.0mm | Pack of 50 | PHCPEUM12 |
| M16 | 24mm | 26.5mm | Pack of 50 | PHCPEUM16 |
| M20 | 30mm | 31.5mm | Pack of 50 | PHCPEUM20 |
| M24 | 36mm | 39.0mm | Pack of 20 | PHCPEUM24 |
| M30 | 46mm | 47.5mm | Pack of 10 | PHCPEUM30 |
| M36 | 55mm | 56.0mm | Pack of 10 | PHCPEUM36 |
How to pick the right bolt cap
- Read the thread size of the bolt or set screw (M10, M12 and so on) and pick the cover of the same size.
- Check the spanner size of the head against the table. Hobson makes these covers to suit AS 1110 hex bolts and set screws; heads made to other standards (structural bolts, for example) can have a bigger spanner size, so measure the head across the flats before you order.
- Check the cover height suits what sits under the cap. The table gives the overall height of each cover.
Polyethylene, black and UV resistant
- Material: black polyethylene, UV resistant. Hobson lists the caps in its nylon range, but they are polyethylene, not nylon.
- Resists acids, greases and oils.
- Protects the bolt head from corrosion and discolouring.
- A cap does not change which bolt a job needs. Choose the bolt finish for where it is: for work exposed to the weather, such as decks and pergolas, Hobson's corrosion guide calls for stainless or hot dip galvanised fixings, and zinc plated bolts are for indoor and non-corrosive places.
Fitting bolt caps
- Install and tighten the bolt or set screw first, as the job requires.
- Check the cap size and spanner size match the head (table above).
- Fit the cap squarely over the hex head.
- To re-tighten or undo the bolt later, take the cap off first: the spanner needs the hex.
Bolt caps in Adelaide
Allmat supplies bolt caps, hex bolts, set screws, nuts and washers to builders, fencers, fabricators and maintenance crews across Adelaide and South Australia. Add the caps to a quote with the bolts they cover and we will price the lot.
Bolt caps for the job
Plug head covers, hex bolts, set screws, nuts and washers are available to order from Allmat for builders, fencers, fabricators, maintenance crews 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 are bolt caps used for?
They cover the hex head of a bolt or set screw. Hobson says the polyethylene cover protects the head from corrosion and discolouring and resists acids, greases and oils. They also give exposed bolt heads a neat finish.
What size bolt cap do I need?
The same thread size as the bolt: an M12 cap for an M12 bolt. Then check the head's spanner size matches the table: M10 suits a 16mm head, M12 an 18mm head, M16 a 24mm head and M20 a 30mm head.
Are these nut caps? Will they fit over a nut?
Hobson lists them for AS 1110 hex bolt and set screw heads only, not for nuts. A nut usually has bolt thread sticking out past it, and Hobson gives only the overall cover height, so we cannot say a cap will fit a particular nut. For a closed, rounded end over a nut, use a dome nut (cap nut).
Can bolt caps be used outside?
Yes. They are black UV resistant polyethylene. Pick the bolt itself for the exposure too: for decks, pergolas and other work open to the weather, Hobson's corrosion guide calls for stainless or hot dip galvanised fixings.
What are the caps made of?
Black UV resistant polyethylene. Hobson lists them in its nylon range, but the material is polyethylene.
Will a cap fit a structural bolt?
Hobson makes them to suit AS 1110 hex bolts and set screws. Structural bolt heads can be larger across the flats, so measure the head and compare it with the spanner sizes in the table before ordering.
How are bolt caps sold?
In packs: 50 for M4 to M20, 20 for M24 and 10 for M30 and M36.
Where can I buy bolt caps 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.
Hex Bolt Head Cover (Bolt Cap): sizes and finishes we supply
11 lines by finish. Pick one above for its product code, pack sizes and dimensions.
| Finish | Sizes | Lines |
|---|---|---|
| Polyethylene blk UV resistant | M4, M5, M6, M8, M10, M12, M16, M20, M24, M30, M36 | 11 |
Data sheets and documents
The documents for the product you choose are listed with the selector above. Here is every Hex Bolt Head Cover (Bolt Cap) document from Hobson Engineering.
All Hex Bolt Head Cover (Bolt Cap) documents (6)
Data sheets and technical data (3)
Did You Know flyers (1)
Guides and articles (2)
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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