On Feb 3, 8:16*pm, "Carl Boyd" wrote:
wrote in message

...





whats better for strength? i have four fasteners to choose from:

8-32

10-24

10-32

1/4"-20

If diameter is fixed, whats stronger, more or less threads?

The load will be shear, i.e., it will try to shear the bolts off,
putting stress on them in that direction.

The material is aluminum.

The screws are stainless steel.

The load will be subject to intense vibration (its an intercooler
mounted on the front of a car) and weighs about 30lbs.

Use Helicoils of similar threded inserts.

Carl Boyd- Hide quoted text -

- Show quoted text -

let me clarify:

the fastener will go through a 1/8" thick steel bracket (unthreaded,
just a hole), and then will enter the threaded aluminum intercooler
wall, which is 3/16" thick.

the intercooler weighs 30 lbs, which makes all of this somewhat
critical i think, especially if the mounting fails, the intercooler
hits the freeway at 80mph pulling the rest of the engine with it...

is the 3/16" thickness of the aluminum too thin to do this?

i dont want to weld to the aluminum because thats just a little too
permanent, i may need to remove the bracket

what about rivets? stainless rivets can handle 1000 lbs shear...the
would be semi-permanent but could probably be drilled out if needed