Maximum loading on 36mm Thread

William,

To calculate this, you will need to provide the answers to these questions:


What is the thread form (Acme, Buttress, 60 degree)?

What is the externally threaded member material? Yield strength, tensile strength?

What is the internally threaded member material? Yield strength, tensile strength?

Is the 60 000 kg acted upon by Earth's full gravity? Are there any other forces?





Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

It depends on how strong the threaded material is. ISO 898-1 is a standard for mechanical properties of bolts, screws, and studs. For a standard M36 x 4 coarse pitch thread, the minimum proof load for a property class 10.9 fastener is 678,000 N. That is about 69000 kg after dividing by acceleration due to gravity to convert force to mass. You can increase that to 718,000 N by using a fine pitch (M36 x 3). Property class 10.9 is obtained by heat treating (quench & temper) suitable steel grades.

If you use the lowest strength, non-heat treated grade (property class 3.6), then the proof load drops to 147,000 N for coarse and 156,000 N for fine.