Acetal Machine Screw, Pan Head, Phillips Drive, #4-40, 1-3/8" Le

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Product Description

Product Description

Machine Screws, also referred to as Machine Bolts, are often used with nuts or driven into tapped holes. They come in a variety of head types and drive styles, but are generally available in smaller sizes.

Acetal resins are characterized by their strength, stiffness, and hardness, and are stable over a wide range of temperatures, humidity, environments, and stress. Acetal has a low coefficient of friction, and absorbs little water, minimizing the effect of moisture on its physical properties. Acetal resists neutral oils, grease, petroleum-based fuels, many organic solvents, alkalis, oxidizing agents and acids, both organic and inorganic. Compared to Nylon 6/6, Acetal is harder and has better water resistance, but lower impact strength and abrasion resistance. Acetal is translucent off white in color.

Pan head fasteners have a low, large cylindrical head with a high rounded top edge for higher tightening torques - these fasteners are often recommended to replace older head styles such as round, binding, or truss-head where possible. The Phillips drive style was originally designed so that the driver would slip out under extreme torque, preventing over-tightening and damage to the fastener or the material.

A threaded fastener's size name includes information about the major external diameter, followed by the threads per inch, which indicates if it is coarse or fine. Coarse threads are better when working with brittle materials; they are sturdier and are easier to thread and unthread compared to fine. Coarse threading also allows for thicker coatings and platings.