Transcript Nylon Inserts 101 – Part 1 - Continental-Aero

NYLON INSERTS 101 – PART 1
by Bobby D.S. Wright of
Tramec Continental-Aero
NYLON GENERAL INFORMATION
• Continental-Aero suppliers use the DuPont 66 or Zytel 101 resin nylon for all
our nylon insert products.
• Continental-Aero products can be easily traced back by the trademarked
Royal Purple Nylon Insert.
• Other fastener manufacturers have trademarked nylon insert colors; ESNA (Red),
Aztech (Orange), Industrial Nut (Blue), SPS/Greer Technologies (Green),
Wyandotte (Gray), Automatic Screw Machine Products (Pink), Abbott Interfast
(Yellow), Generic (White/Clear).
• Per the Harvard Industries Publication FSCM 72962, page 62, the working
temperature of Dupont 66 or Zytel 101 is: -70°F and 250°F.
WHY WOULD NYLON VISUALLY
APPEAR TO FAIL?
• There are only six (6) visual symptoms on why a nylon insert will appear to
have failed:
• Brittleness – cracking, extremely soft, dust like with white edges where nylon
breaks off.
• Pig tailing – pieces of nylon are curling and/or breaking off as the mating end is
protruding through the nylon, like a pig’s tail.
• Undersized inner diameter of the nylon – nylon mushrooms or expands upward as
the mating end protrudes through the nylon.
• Melting during installation – literally melts.
• Pops out during installation – the nylon pops out of the nut.
• Off center – not centered.
WHAT ACTIONS ARE TO BE TAKEN?
• If any of the symptoms appear, a manual installation using the appropriate
sized socket, 3/8 or ½ driver or any other human powered hand tool (i.e.,
combination wrench, adjustable wrench, pipe wrench, etc.).
• Manual installation is the practice of “human power” not pneumatic
operated tooling.
• The nylon insert does not have knowledge of what type of installation
practice is used (manual or pneumatic), therefore when manually installing
and the problem does not replicate the original compliant, then the nylon is
conforming and the root cause is the application of installation by the End
User.
BRITTLENESS OF NYLON
• Physical Appearance: cracking, extremely soft, dust like with white edges
where nylon breaks off. This is very rare, therefore a picture of an example
can not be provided.
• Possibility of Root Cause: this is the rarest of the six (6), as less than 1% of
nylon issues are considered brittle, due to the lowest working temperature of
the nylon at -70°. Most likely the issue is that the mating end has a burr or
nick on the threads that are cutting into the nylon (see Pig Tailing).
PIG TAILING OF NYLON
• Physical Appearance: pieces of nylon are curling and/or breaking off as the
mating end is protruding through the nylon,
like a pig’s tail.
• Possibility of Root Cause: Approximately 1% of nylon issues are considered
pig tailing, however the most likely issue is that the mating end has a burr or
nick on the threads that are cutting into the nylon.