I said STI, not STD. I install thousands of Screw Thread Inserts, AKA
Heli-Coils, every year. The last 4000 inserts my customer has
provided are from Re-Coil. These inserts have been really troublesome.
The tangs don't break off easily. Even with being bent 90 degrees they
don't break off and need to be bent back. On top of that the tangs are
too long so that the installation tools that are the screw in type
get caught on the end of the tang instead of in the corner. Then when
the insert is driven into the hole it catches instead, the tool, which
is made of the softest steel I've ever seen, ends up being driven
through the insert and both the insert and tool are ruined. But it
gets worse. I gauge ALL the holes now before and after the STI gets
installed because a bunch of parts were rejected for being tight. All
the tapped holes gauge fine, not a single one has been undersized. But
about 40% of the holes gauge undersize once the STI is in place. This
means driving either driving out the STI and installing another or
running a roll tap through the hole. So I have been running a tap
through. Which is slow. The tap has to be spun at a low RPM or it will
gall on the SS insert. This ruins the tap and drives the insert out. I
also have to use a high pressure type oil on the tap which then needs
to be washed off. All this fooling around has turned a good money
making job into a money losing headache. So we are looking for inserts
that can be trusted. Besides Heli-Coild brand inserts does anybody
here have any experience with STI of another brand? The Re-Coil brand
ones have just gotten so bad. By the way, it doesn't matter if I
install the inserts by hand with the RE-Coil type tool, by hand with
the thread in type tool, by hand with a pre-winder, under power with a
pre winder, or under power without a pre-winder. I have eliminated
everything else and it is the crappy inserts that are the problem.
Eric