Countersunk Post Torx Security Machine Screws have a flat head and countersunk that sits flush with the surface of the material rather than protruding above like other types of heads and a tamper resistant Post Torx drive which is extremely difficult to install and remove without the matching tool. The ideal security screw to protect and prevent unauthorised removal Post Torx Drive is a six (6) lobe design with a solid post (pin) in the centre of the recess to provide increased resistance to tampering. The head is flat with a countersunk which is commonly used in fixtures where the screw must be partially or fully concealed. Designed for medium torque applications. Can be used to fasten components together by means of through holes and securing with a nut at the other end or screwed into a tapped hole with the matching thread Also known as: Tamper Resistance Screws Post Pin Screws Dome Head Torx Screws Pin Head Machine Screw Material / Coating: Stainless Steel A2-70 G304 is the most popular grade of stainless steel. It is aesthetically pleasing to the eye and very practical because of its excellent corrosion protection in most environments. Most products can be identified by the following markings: A2 A2-70 304 or G304. Stainless steels are largely non-magnetic but it is common for stainless steel fasteners to show a small degree of magnetism which is a result of work-hardening during the manufacturing process Can Stainless corrode?: Stainless steel is corrosion-resistant but not corrosion-proof and corrosion can occur if the material is installed or handled incorrectly. The use of tools and drills made from conventional steel during the installation of stainless steel fasteners may also lead to problems. Even the hardest of tools can produce debris that leaves minute steel particles on the stainless steel fastener surfaces or in pre-drilled holes. It is these particles that often rust when exposed to moisture or oxygen and can result in a stained or tarnished finish to the stainless steel material Thread Pitch (Metric): Pitch means the distance between the peaks of two threads along a screw bolt or fastener expressed in millimetres (mm). Used when referring to Metric parts. For example a thread pitch of 1.50mm means that the distance between one thread and the next is 1.50mm Fastener length: is generally measured from the point where the surface of the material will be when the fastener is installed to the end of the fastener. 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.