What is GM 500 M 9.8 screw?

Answer 1

GM500M: Mechanical and Material Requirements for Metric Externally Threaded Fasteners.

This standard covers the mechanical and material requirements for six property classes of carbon and alloy steel externally threaded metric fasteners in nominal thread diameters M1.6 to M36, inclusive, suitable for use in general engineering applications. Products included are bolts, screws, studs, U-bolts and sems and hardness of HRC39 max. Tapping screws, thread rolling screws, self drilling tapping screws and set-screws are NOT included.

The term "stud" as referred to herein applies to a cylindrical rod of moderate length, threaded on either one or both ends or throughout its entire length. It does not apply to headed, collared or similar products which are more closely characterized by requirements shown herein for bolts.

For specification purposes, this standard treats U-bolts as studs. Thus, wherever, the word "studs" appears, "U-bolts" is also implied. U-bolts covered by this standard are those used primarily in the suspension and related areas of vehicles. (Designers should recognize that the "U" configuration may not sustain a load equivalent to two bolts or studs of the same size and grade; thus actual load carrying capacity of U-bolts should be determined by saddle load tests.)

Requirements for the 6 property classes, 4.6, 4.8, 5.8, 9.8, and 10.9 are essentially identical with requirements given for these classes in ISO 898/1 and ASTM F568.