Sat. Apr 20th, 2024

Screws come in many shapes, sizes and types to suit an endless number of construction tasks. Choosing the wrong kind can split wood or affect the structural integrity of a building. But, just like nails and wires, screws are rated by a combination of three essential measurements: diameter, thread spacing (or “twist”) and length.

Screw diameter, also called a gauge, measures the size of the screw’s cylinder and is expressed in inches. A common gauge is #2 through #8, although heavier materials such as thicker metals might require a higher gauge. The thickness of the material into which a screw will be installed is another factor in selecting a screw, as the screws must be strong enough to penetrate the substrate without bending or breaking.

The screw’s thread spacing, also known as the thread pitch, expresses the distance between one thread and the next. The screw may be labeled with this value in inches or metric mm. It is not uncommon for multiple pitch values to be available for a given diameter, but the number most commonly used in US sizes is 35 or 40 threads per inch.

Finally, the screw’s length relates to how far into the substrate the screw should extend, not including the head (unless it is a countersunk head). Screw heads can be flat, oval or countersunk and drive type can range from square to Phillips or to a variety of hex or torsion drive systems. 3/4 to mm

By Admin

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