Most kids like to take things apart. The ones that learned to reliably
reverse the process usually go on to become engineers.

I first learned about these fasteners over 30 years ago when I was
designing and building IMSA race cars. I was visiting another car
builder, Dave Kent, in Los Angeles and he took me to an aerospace
fastener surplus store where you could buy "sweepings" from the various
aerospace facilities. You could get every kind of cool high performance
fastener and pay by the pound! If I knew then what I know now I would
have mortgaged the farm and bought the entire store. A couple of years
later there was a scandal where where people were buying up these
surplus parts, repackaging them and selling them back to the market as
new. The FAA cracked down and my "Fastener Heaven" store vaporized and
is now a tattoo parlor.  BTW, it was Dave that introduced me to WLS
coatings. Dave also had a penchant for topless bars and double Dewer's
up, but that is way off topic.

Tridair fasteners are positive retention fasteners, originally designed
for supersonic aircraft. Dzus and Camlock fasteners are "fixed force"
spring type. When you use a spring fastener you produce a fixed clamping
force at the fastening interface. This is bad news in high vibration
environments as the vibration can momentarily separate the two clamped
parts, allowing them to move laterally and cause fretting and wear. If
you examine most spring fastener installations that have been in service
for a while you will see indicia of wear proximal to the fastener.

The Tridair fasteners are different because there is no mushy spring in
the clamping system. Also the OD of the female "screw" is a close
tolerance fit to the ID of the receiver. This provides  positive
clamping without the wiggle.

HOW THEY WORK

There is a reason these things are expensive.

Refer to the pictures below. All the magic is in the receptacle. The
housing is capped by a stud that has a multi start male thread. Inside
the housing is a coaxial barrel that contains a spring that prelaods an
axial sliding plate. On the bottom of the barrel and the top of the stud
heads are radial teeth that engage each other.

During assembly, slots on the end of  the screw engage tabs on the
sliding plate. Other tabs on the perimeter of the sliding plate engage
slots in the barrel so that as the screw turns the sliding plate the
plate turns the barrel, causing the teeth to on the barrel to rotate
against the teeth on the stud. This produces a clicking noise during
assembly and removal. It also prevents the fastener from loosening in
service.

Installation and use tips:

Try to only use one grip length. I used -2s. This eliminates the
possibility of using a wrong length. You can grind down or bid up the
receiver mounting area to make the grip distance within the fastener's
range.

The retainer clip is not a requirement.  Having the screws come off of
the  cowling  eliminated the possibility of having them scratch  the
paint during reassemble.

Use a reamer (0.251") to size the holes with the cowling mated to the
fuselage. Repeat after painting and then install the receivers.

Periodically wash out the screws and receivers and relubricate with
something better than WD40 (e.g. LPS #2 spray lubricant).

Remember, paying for quality is a tough decision to make but an easy
decision to live with.

Regards
Brent Regan