[CQ-Contest] Aluminum fatigue cracks and scratches - treatment?
aa4lr at arrl.net
Mon Aug 16 22:15:26 EDT 2004
On Aug 5, 2004, at 10:01 PM, Eric Scace K3NA wrote:
> Cracks due to resonances and vibration-induced fatigue can be
> halted. Drill a small hole at the end of the crack (the end which
> is propagating into the heart of the tubing) clear through the wall of
> the aluminum. It is more difficult for a tear to continue to
> develop past the hole. (This technique is often used in cymbals,
> where a poor-quality casting can cause the outer edge of the
> cymbal to crack due to fatigue. Works like a champ.)
This technique is also used in aircraft. In light aircraft, it is not
unusual to see three or four small cracks in high-vibration areas (such
as the engine cowling) stop-drilled in this manner.
This technique is also effective with acrylic.
Bill Coleman, AA4LR, PP-ASEL Mail: aa4lr at arrl.net
Quote: "Not within a thousand years will man ever fly!"
-- Wilbur Wright, 1901
More information about the CQ-Contest