Type A Button Post Torx Screw
Class 3 Type A button head screw with a Post Torx (pin Torx) security drive, #18-9 x 65mm.
About the Type A Button Post Torx Screw
This is a tamper resistant button head screw with a pin Torx drive from Hobson's DRiLLX range, for fixings that should only come out with the matching security bit. It is a Class 3 coated Type A screw, #18-9 x 65mm, in boxes of 250 (the Dover White large wafer stitching screws are on the stitching screws page). The guide below explains the name, the bit it needs, the Class 3 coating and what Hobson does not publish for this screw.
Also called Type A button head screw or button head post Torx screw.
Features
- Type A button head, Post Torx security drive
- #18-9 x 65mm
- Class 3 coating
Applications
- Tamper resistant fixing with a pin Torx bit
What this screw is
Hobson lists it as a Type A button post Torx screw (code T9PA3BT1809065) in the multi-use section of its DRiLLX range, Class 3 coated to AS 3566. Taking the name apart:
- Button head: a low, rounded head, one of the head styles on Hobson's self-drilling screw identification sheet.
- Post Torx: a drive type that Hobson's identification sheet lists separately from plain Torx. It is a Torx (six-point star) recess with a pin in the centre, so an ordinary Torx bit will not fit. It needs a pin Torx bit, which has a hole in the tip to clear the pin.
- Type A: Hobson's name for this screw, filed under Type A point. Hobson's product photo shows a sharp point and a coarse thread, not a drill point.
- Material: Hobson lists it as hardened C1022 steel.
- #18-9 x 65: gauge 18, 9 threads per inch, 65mm long. At 9 threads per inch it is coarse thread by Hobson's definition (up to 16 TPI). Hobson's gauge chart stops at 14 gauge (6.3mm), so no diameter is published for #18.
Driving a post Torx screw
- Use a pin Torx bit (Hobson calls them post Torx socket bits) or a pin Torx socket key. We carry them in a range of T sizes.
- Hobson does not publish the T size for this screw, so we do not state one.
Size we carry
One size, sold by the box. Select the row to open it.
From our product data and Hobson's stocklist (CL3 TYPE A BUT PST TX: 18-9X 65). Size as gauge-TPI x length in mm. Tap a number to show it in the selector above.
| Screw | Code | Head | Drive | Coating | Box |
|---|---|---|---|---|---|
| #18-9 x 65 | T9PA3BT1809065 | Button | Post Torx (pin Torx) | Class 3 (AS 3566) | Boxes of 250 |
What Hobson does not publish
Hobson has no data sheet for this screw among its documents. Hobson lists the material as hardened C1022 steel but gives no application, thickness, pilot hole, Torx size or strength values. So do not use it for a structural or safety-critical fixing or anything holding people or loads: Hobson publishes no rating for it, and those jobs need a rated fixing specified by an engineer or designer.
If you came here for stitching screws: the screws that join roof and wall sheet laps, including the Dover White ones, are on our stitching screws page with Hobson's pull-out values.
Class 3 coating and corrosion
Class 3 is a corrosion class for self-drilling screws (AS 3566). Hobson's finish comparison describes its Class 3 coating as mechanically galvanised, 21 microns, moderate corrosion resistance, for external use in mild, moderate industrial or marine environments (ISO 9223 categories C2 and C3).
Hobson's corrosion warranty (effective September 2025) covers self-drilling screws, and this is a Type A sharp point screw, so we make no warranty claim for it. As a guide to the coating only: that warranty does not recommend Class 3 self-drilling screws in C4 or C5.
Post Torx screws in Adelaide
Allmat supplies Hobson DRiLLX screws, pin Torx bits, stitching screws and tek screws to builders, roofers and fabricators across Adelaide and South Australia. Add the screws and the bit to a quote and we will price the lot.
Button head post Torx screws to order
Class 3 Type A button head post Torx screws, the pin Torx bits to drive them, stitching screws and tek screws are available to order from Allmat for builders, roofers, fabricators 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 post Torx screw?
A screw with a post Torx drive: a Torx star recess with a pin in the centre. Hobson lists post Torx as its own drive type. A plain Torx bit will not fit; it needs a pin Torx bit with a hole in the tip.
What bit do I need for this screw?
A pin Torx (post Torx) bit or socket key. Hobson does not publish the T size for this screw.
Is this a stitching screw?
Hobson lists no application for it. It is not among the stitching screws in Hobson's DRiLLX guide; Hobson files it as a Type A button head post Torx screw. For roof and wall sheet laps, including Dover White, use the screws on our stitching screws page.
What does #18-9 mean?
Gauge 18 with 9 threads per inch. That is coarse thread by Hobson's definition (up to 16 TPI). Hobson's gauge chart only goes up to 14 gauge, so it publishes no diameter for #18.
Is Class 3 OK near the coast?
Hobson's finish comparison rates its Class 3 coating for C2 and C3 environments, and its self-drilling screw warranty does not recommend Class 3 in C4 or C5 (severe marine and very severe marine sites).
How many come in a box?
Boxes of 250.
Where can I buy post Torx 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.
Type A Button Post Torx Screw: sizes and finishes we supply
1 line by type and finish. Pick one above for its product code and pack sizes.
| Type | Finish | Sizes | Lengths | Lines |
|---|---|---|---|---|
| Button | Class 3 | #18-9 | 65 | 1 |
Data sheets and documents
The documents for the product you choose are listed with the selector above. Here is every Type A Button Post Torx Screw document from Hobson Engineering.
All Type A Button Post Torx Screw documents (6)
Data sheets and technical data (4)
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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