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2-Hole Countersunk Self Tapping Security Screw

2 Hole Countersunk Head Security Self Tapping Screws

2-Hole Security Screws have two holes drilled into their head, requiring a special insert bit to insert and remove. These two holes can be drilled at different distances between centres. It is therefore advisable to always purchase the screws and corresponding bits from the same supplier.

The two pin drive is designed to offer security whilst presenting an aesthetically pleasing finish, but is more prone to cam-out than other security screws such as the Pin Hex range.

The security drive design of the countersunk 2-hole security screw makes it suitable for low to medium torque applications and is a two-way re-usable fixing, making it an ideal medium-security fastener for applications where maintenance is required.

Generally used in areas where the aesthetic appearance is more important than security, these screws can often be found on trains or in public lifts.

They are also known as Snake Eye Screws, Pig Nose Security Screws, Two Pin and Spanner Drive Screws.

When tightening the screw, the drive bits can be prone to bending or breaking after prolonged use, so we recommend purchasing additional drive bits for back-up purposes.

Available as standard in stainless steel, with a range of sizes and materials available to order.

Gauge / Length (mm) 1/4″ (6.5) 3/8″ (9.5) 1/2″ (13) 5/8″ (16) 3/4″ (19) 1″ (25) 1 1/4″ (32) 1 1/2″ (38) 1 3/4″ (45) 2″ (50) 2 1/2″ (63)
No.4 (2.9mm)
No.6  (3.5mm)
No.8  (4.2mm)
No.10  (4.8mm)
No.12  (5.5mm)
No.14  (6.3mm)

2 Hole countersunk self tapper technical drawing

No.4 No.6 No.8 No.10 No.12 No.14
DK (mm) 5.5 6.6 7.8 8.9 10.1 12.3
K (mm) 1.7 2.1 2.5 3.0 3.4 3.9
TOOL SIZE No.4 No.6 No.8 No.10 No.12 No.14

*For guidance purposes only

2 Hole Countersunk Self Tapping Security Screw