Countersunk Phillips Machine Screws can be used to fasten components together by means of through holes and securing with a nut at the other end or they are screwed into a tapped hole with the matching thread Machine screws are fully threaded and have uniformly threads, meaning they maintain the exact same diameter throughout the entire length of the threaded section of the fastener, unlike self tapping or chipboard screws which have tapered threads. As the name suggests, these screws can be used to fasten components in machines, tools, appliances and electronic devices. A thin layer of Zinc is applied by either electroplating or mechanically. It is intended to be used internally, whilst some people use it externally it isnt recommended if corrosion may be a concern, instead search our Stainless steel range 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.