5mm x 25mm Alpha Post Hex Insert Security Standard Driver Bit HEXSE525

About Post Hex Security Bits

Post Hex security driver bits are the tamper-resistant version of standard hex bits. The bit tip has a centre hole drilled into it that clears the central pin found in Post Hex security socket cap screws. A standard hex bit will NOT engage a Post Hex screw - the centre pin blocks the bit from seating.

Frequently Asked Questions

How to Measure

Sizing Post Hex security bits are sized by hex AF (across flats) dimension identical to standard hex bits - 1.5mm to 10mm metric, 1/16" to 3/8" imperial. The centre hole in the bit tip clears the central security pin in the fastener. A standard hex bit will NOT engage a Post Hex screw.

How to measure a driver bit Pick the bit by the AF (across flats) dimension of the hex tip (1.5mm to 10mm metric or 1/16" to 3/8" imperial). The shank is the bit's clamping end - 1/4" hex is the universal standard across cordless drivers, impact drivers and bit holders. The overall length determines reach: 25mm insert for general use, 50mm to 90mm power bits with a torsion zone for impact drivers, 116mm for Hilti autofeed, long-shank Allen keys for recessed socket cap screws. Cross-check the tip dimension against the screw head before driving - an undersized bit cams out and strips the recess.

Measurements Accurate to the relevant standard and should be used as a guide only. They are either hand-measured or taken from suppliers' catalogues. We only stock Alpha for this product; substituting another brand is rare and would always be confirmed with you first.

Magnetism

This product is magnetised. The tip / cup retains a fastener through alignment and engagement, which speeds work in overhead, awkward or one-handed install scenarios. Across the wider Driving range, magnetised bits, holders and nutsetters speed install by holding the fastener on the tip through alignment; non-magnetised tools are preferred for electronics, magnetic-sensor proximity and any work where stray magnetism on the fastener would cause downstream issues. Check the specification table above for the per-SKU value before ordering for magnetism-sensitive applications.

Resources

About the Brand

Alpha · Sheffield Group · Australian

Alpha is the Sheffield Group's premium drilling, cutting and fastening brand. Australian-owned, Sheffield has supplied industrial and trade markets since 1957 and is one of the country's largest distributors of cutting tools and accessories.

Range: The Alpha range covers Gold Series HSS jobber drill bits, HSS Cobalt drill bits, Bi-Metal Cobalt holesaws, TurboBORE spade bits, heavy-duty timber augers, SDS Plus masonry bits, countersinks, ONSITE+ impact-rated step-tip drill bits, and the ThunderMax range of impact-driven accessories.

Positioning: Premium-quality, production-grade tools at trade pricing. Same-day dispatch from BNA Brisbane.

Pricing & Delivery

Includes GST, a Tax Invoice and Free Standard Delivery anywhere in Australia.

Buy with Confidence

15+ years selling online · 25,000+ stock lines · 200 million pieces ex-stock in Brisbane QLD.

Disclaimer

Technical data Researched and compiled from numerous industry sources for the sole purpose of providing basic information. All material is advisory only and its use by anyone is entirely voluntary. Reliance on it for any purpose by anyone is at the sole risk of that person, and Bolt and Nut Australia is not responsible for any loss, claim or damages arising therefrom. In developing this information, Bolt and Nut Australia has made a determined effort to present it accurately.

Product Photos & PDF Data Sheets Represent the product type, not exact size. PDFs are a reference guide only. Specifications may change without notice.

If you see any problems with any of our specifications or you require additional information please contact us.