WinterDeere
Super Member
- Joined
- Sep 6, 2011
- Messages
- 5,332
- Location
- Philadelphia
- Tractor
- John Deere 3033R, 855 MFWD, 757 ZTrak; IH Cub Cadet 123
Oh, yeah... there is definitely a huge range of "stainless" out there, especially now with Asian vendors flooding the market through Amazon.com and the like.
Even among legitimately-graded stainless, there's 18-8 (ANSI 304) versus 306 and others. You might use 306 underwater in a marine environment, giving up some strength, but 18-8 (304) for mounting a patio umbrella. Probably 99% of the hardware I stock is 18-8, made to ANSI 304 standard.
18-8 stainless is pretty close to grade 2 common hardware, in terms of ultimate tensile strength. Yeah, not the strongest stuff available, but you can usually up-size the bolt as needed to achieve the required tensile strength. The point was only that thread failures should not happen, the bolt should fail way before the thread, in a matched-materials situation with nearly any UN fastener system.
This was actually one of the design criteria 100 years ago for the "Unified National" fastener system we use today, that minimum thread pull out stregnth be something like 4x the corresponding fastener tensile strength. Their reasoning was that it is usually much easier and cheaper to extract the remnant of a broken bolt or stud, than to re-thread a female thread. So when properly used, the system almost gaurantees the fastener will fail before the female thread.
Things like galling between stainless fasteners can frustrate this system, but antisieze on the threads will almost always fix that problem.
Even among legitimately-graded stainless, there's 18-8 (ANSI 304) versus 306 and others. You might use 306 underwater in a marine environment, giving up some strength, but 18-8 (304) for mounting a patio umbrella. Probably 99% of the hardware I stock is 18-8, made to ANSI 304 standard.
18-8 stainless is pretty close to grade 2 common hardware, in terms of ultimate tensile strength. Yeah, not the strongest stuff available, but you can usually up-size the bolt as needed to achieve the required tensile strength. The point was only that thread failures should not happen, the bolt should fail way before the thread, in a matched-materials situation with nearly any UN fastener system.
This was actually one of the design criteria 100 years ago for the "Unified National" fastener system we use today, that minimum thread pull out stregnth be something like 4x the corresponding fastener tensile strength. Their reasoning was that it is usually much easier and cheaper to extract the remnant of a broken bolt or stud, than to re-thread a female thread. So when properly used, the system almost gaurantees the fastener will fail before the female thread.
Things like galling between stainless fasteners can frustrate this system, but antisieze on the threads will almost always fix that problem.