Stainless Fasteners
Post Hex Bit (Pin Hex)
Security driver bit for Post Hex (pin-in-hex) tamper-resistant fasteners, bored down the centre to clear the pin.
About the Post Hex Bit (Pin Hex)
Pin hex security bits are hex bits with a hole down the centre to clear the pin in a pin hex security screw, for fitting and removing tamper resistant screws on public fittings. Hobson calls them post hex socket bits; they come in 2.5, 3, 4, 5 and 6mm and 3/32 to 7/32 inch, plain steel, sold individually. Choose the hex size above; the guide below shows which screw each bit drives and why the size on the label is the hex, not the thread.
Also called pin hex bits, security hex bits or tamper proof hex bits.
Features
- Post Hex security driver bit
- Central bore clears the pin
- Metric 2.5 to 6mm hex
- Imperial 3/32-7/32
- For pin-in-hex fasteners
- Plain finish
Applications
- Driving Post Hex security screws
- Installation and removal
- Maintenance
What a pin hex security bit is
A pin hex (post hex) security screw has a hex socket, like an Allen key screw, with a pin standing up in the centre. An ordinary hex key or hex bit will not go in. A pin hex security bit has a hole bored down the centre of its tip that clears the pin, so it seats in the socket and turns the screw.
Our bits are plain steel and sold individually. Hobson also makes the same drive as an L-shaped key (post hex socket key) in the same ten sizes, for turning by hand or where a driver will not reach; those keys are on the security bits page, linked below.
The size on the label is the hex, not the screw thread
Hobson labels the metric bits M2.5, M3, M4, M5 and M6, but Hobson's screw descriptions show that number is the hex size in mm, not the thread of the screw. The bit labelled M4 is a 4mm hex, and it drives M6 screws; an M4 screw takes the 2.5mm bit. The selector shows the bits by hex size (2.5mm to 6mm) to avoid that mix-up.
Which pin hex bit for which security screw
The hex size is printed in the description of every pin hex screw we carry (for example "P/HEX 4.0" on the M6 screws). Select a row to open that bit in the selector.
Each pin hex security bit we carry and the pin hex screws in our range it drives, from the hex size in Hobson's screw descriptions. All the screws are 304 stainless; self-tapping lengths in inches, machine screw lengths in mm. Bits are sold individually. Tap a number to show it in the selector above.
| Range | Hex size | Hobson label | Drives these pin hex screws |
|---|---|---|---|
| Metric | |||
| Metric | 2.5mm | M2.5 | #8 countersunk self-tapping screws (1/2 to 1-1/2 inch); M4 button machine screws (6 to 30mm); M4 countersunk machine screws (8 to 25mm) |
| Metric | 3mm | M3 | #10 countersunk self-tapping screws (1/2 to 1-1/2 inch); M5 button machine screws (10 to 30mm); M5 countersunk machine screws (10 to 30mm) |
| Metric | 4mm | M4 | M6 button machine screws (10 to 50mm); M6 countersunk machine screws (10 to 50mm) |
| Metric | 5mm | M5 | M8 button machine screws (16 to 60mm); M8 countersunk machine screws (16 to 40mm) |
| Metric | 6mm | M6 | No pin hex screw in our range; for other pin hex screws with a 6mm hex |
| Imperial | |||
| Imperial | 3/32 inch | 3/32 | No pin hex screw in our range; for other pin hex screws with a 3/32 inch hex |
| Imperial | 1/8 inch | 1/8 | No pin hex screw in our range; for other pin hex screws with a 1/8 inch hex |
| Imperial | 5/32 inch | 5/32 | No pin hex screw in our range; for other pin hex screws with a 5/32 inch hex |
| Imperial | 3/16 inch | 3/16 | No pin hex screw in our range; for other pin hex screws with a 3/16 inch hex |
| Imperial | 7/32 inch | 7/32 | No pin hex screw in our range; for other pin hex screws with a 7/32 inch hex |
Quick list by screw
- Machine screws, button or countersunk: M4 takes 2.5mm, M5 takes 3mm, M6 takes 4mm, M8 takes 5mm.
- Countersunk self-tapping screws: #8 takes 2.5mm, #10 takes 3mm.
- The 6mm and imperial bits (3/32 to 7/32 inch) suit pin hex screws from other ranges with that hex size; we have no pin hex screw that takes them, so check the hex on your screw first.
Using a pin hex bit
- Match the hex size to the screw (table above). A smaller bit will round out the socket.
- Seat the bit fully, so the pin sits inside the hole in the tip, and keep the bit in line with the screw.
- Drive at a steady, moderate speed and stop when the head is snug. Stainless screws can gall (lock up in the thread) if driven too fast or overtightened; Hobson suggests slowing the installation speed and a thread lubricant containing molybdenum disulphide.
- Keep the bits secure. Pin hex screws stop casual tampering; anyone with the matching bit can still remove them.
Pin hex or pin Torx?
Both are tamper resistant drives with a centre pin, and each needs its own bit. Pin hex screws in our range run from M4 to M8 and #8 and #10; pin Torx screws run from M3 to M12, 3/8 UNC and #6 to #14, and pin Torx barrel nuts are also made. If you are choosing a drive for a new job, the pin Torx range is the wider one; if you are maintaining existing pin hex screws, match the hex size above.
Pin hex bits in Adelaide
Allmat supplies pin hex and pin Torx bits, keys and security screws to councils, sign makers, maintenance crews and builders across Adelaide and South Australia. Add the bits to a quote with the screws, and we will price the lot.
Pin hex bits with the screws they drive
Pin hex bits, pin hex L keys and tamper proof security screws are available to order from Allmat for councils, sign makers, playground and facility maintenance crews, builders 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 pin hex security bit?
A hex bit with a hole in the centre of its tip, so it fits over the pin in a pin hex (tamper resistant hex) screw. Ours come in 2.5, 3, 4, 5 and 6mm and 3/32, 1/8, 5/32, 3/16 and 7/32 inch.
What size pin hex bit for an M6 security screw?
4mm, for our M6 button and countersunk pin hex screws. M4 screws take 2.5mm, M5 take 3mm and M8 take 5mm; #8 countersunk self-tapping screws take 2.5mm and #10 take 3mm.
Why is the 4mm bit labelled M4?
Hobson's label gives the hex size, not the screw thread. The M4 labelled bit is a 4mm hex and drives M6 pin hex screws.
Will a normal Allen key fit a pin hex screw?
No. The pin in the centre of the socket blocks a solid hex key or bit. You need a pin hex bit or key of the same hex size, which has a hole for the pin.
Is there a pin hex key instead of a bit?
Yes. Pin hex (post hex) L keys come in the same ten sizes, 2.5 to 6mm and 3/32 to 7/32 inch, for turning by hand.
How are the bits sold?
Individually, one bit per size. Add the bit to the order with the security screws.
Where can I buy pin hex bits 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.
Post Hex Bit (Pin Hex): sizes and finishes we supply
10 lines by finish. Pick one above for its product code and pack sizes.
| Finish | Sizes | Lines |
|---|---|---|
| Steel | 2.5mm, 3mm, 4mm, 5mm, 6mm | 5 |
| Steel | 3/32, 1/8, 5/32, 3/16, 7/32 | 5 |
Data sheets and documents
The documents for the product you choose are listed with the selector above. Here is every Post Hex Bit (Pin Hex) document from Hobson Engineering.
All Post Hex Bit (Pin Hex) documents (3)
Data sheets and technical data (2)
Guides and articles (1)
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 security screws