Are there stronger bolts?

[monte55]

Is there a stronger bolt I can use better than a grade 8? What does"AN" desigination mean?

[KBar]

Nick, we use a Grade 9 at work. The only trouble is, the grade 9 is more brittle than the grade 8 and it will break quicker, however the grade 9 does have more holding stength.

[monte55]

KBar........thanks for the comeback. How are they stronger? Shear load or enlongation(sp)or both............Nick

[AlxJ64]

I always heard that "AN" meant Army-navy... which is a standardized style of hardware and fittings.

Also I have seen and have used Grade 9 hardware. Typically its only in a clamping situation as Grade 8 works great in shear and in tension. Keep in mind the strength and hardness of the hardware vs. the hardness of the material you are bonding. What will fail first? Is that catastophic failure? In high fatigue areas you often want your hardware to have similar properties as your clamped materials. Unless the hardware is only acting as a friction causing clamping force.

Also grade B7 has a fairly high yeild value but with more of an elastic range than that of the typical Grade 8 hardware...

Its more in the application of the hardware than in the actual strength of the hardware. You'd be amazed at what you can put Grade 5 and 8 through if you spec it properly.

[Vicegrip]

I am no ex-purt so take this with a grain of salt.

Depends on what you are doing with it iin high stress apps. 120,000 psi is about as high as it goes for Steel bolts using ASTM ratings. That is grade 8. There are bolts that have been made from certain alloys and or are subjected to treatments that are grade 8 but have better high or low temp use.

There ARE bolts that are higher that 120,000 psi but you might have to go out of the realm of steel.

I was told that AN = Airframe - Navy

[turbo38t]

Just browse through a McMaster-Carr catalog or Grainger catalog. There are some stronger bolts. Especially some of the alloy ones. Dave

Is there a stronger bolt I can use better than a grade 8? What does"AN" desigination mean?

[fabricator]

This pretty much answers most questions. http://www.unified-eng.com/scitech/bolt/boltmarks.html

[KBar]

KBar........thanks for the comeback. How are they stronger? Shear load or enlongation(sp)or both............Nick

I actually prefer the grade 8 over the grade 9 because of the shear strength, the grade 9 will snap quick with a sharp impact or sizable load against it. But because of technical & liability issues, we need to use the grade 9.

[J hall]

FWIW, if you have trouble with bulk bin grade 8 bolts, take a trip to your local CAT dealer. They are known for quality fasteners.

[walker]

I am curious to know what hte application is. Generally if a grade 8 bolt can't handle the stress you need either more of them or a bigger diameter bolt.