iBoaterer wrote:
In article , says...
On 12/31/2012 5:44 PM, Wayne.B wrote:
On Mon, 31 Dec 2012 15:23:44 -0600, Califbill
wrote:
The fix is not stronger than the base metal, but there
is more base metal involved. Therefore the fix is stronger.
===
Sounds right to me. The heli-coil is bigger than the plug so it has
more contact area (gripping surface) with the aluminum head. All
other things being equal, it should be stronger than the original.
What I have been saying all along..
You are wrong. Once again, the base metal THICKNESS has not changed. the
base metal thickness is what gives it X in tensile strength (or
compressive strength for that matter, although here we are strictly in
tension) Okay, now there is a cone of influence DIRECTLY proportionate
to the thickness of the base metal. You only WEAKEN that base metal by
enlarging the whole. The perfect cone of influence is a 45 degree angle,
conical of course. IF that cone of influence doesn't fully develop
because of a lack of thickness of base metal, then it's weaker than it
could be. I doubt you and your dummies will get it, but I'm sure Wayne
will.
OK. Use this example. You use a 10-32 screw in a sheet of metal. Does
not matter what material really. How much force to pull out that screw is
required? Now, same piece of base material. Drill and tap for a 4"-32
screw. Install screw. How much force required to pull that screw loose?
You should not make big bets without knowing the odds. Same principal if
you welded on a pad-eye and increased the size of the pad. Takes more
force to rip it loose.