 General
Design Data:
The internal mechanisms of the CM1 rubber cowling mounts are the same
as the MS245 and MS213 adjustable receptacles. The main components are
a threaded barrel, threaded insert, locking clip and anti lock
pin. The insert is the portion that the fastener stud locks into. It
has two vertical grooves machined on the outside diameter. These grooves
are where the locking clip engages to prevent the insert from rotating
after the proper depth has been acquired. For the initial adjustment
we have installed an anti-locking pin underneath the locking
clip on the outside diameter of the barrel. This pin keeps the locking
clip from engaging until the proper fit is determined. These pins should
be left in for the installation and panel fitting process but must be
removed prior to flight or return to service.
Installation
and Depth Adjustment:
After the fasteners, grommets, receptacles or shock mounts are
installed, position the cowling or panel and engage the MilSpec
C-Spec
fasteners into the receptacle. The studs should lock with the head protruding,
this is normal. To perform the initial adjustment of the receptacle,
simply turn the stud clockwise just like tightening a screw until the
head of the stud is flush with the grommet (or stud cup when using 2600/2700/2800
series). Proceed around the cowling or panel performing this operation
at all locations. Do not go beyond flush as this will over stress the
stud assembly.
Now that all locations have been fitted,
the cowling or panel can be removed and the anti-locking pins can be
removed from the receptacles. To unlock the fasteners without spinning
the insert you will need some fancy wrist action and a bit of a feel
for it. The way to do this is to push in slightly on the
stud head and with a quick motion, release pressure while giving the
stud a 1/4 turn counterclockwise. This is not hard but, may take a few
attempts to get it just right. Once the studs are unlocked and the cowling
or panel is removed, go to the receptacle and remove the anti-lock pin.
If the pins are not removed and the inserts are not properly locked,
the fasteners could potentially unlock in service.
The locking clip may not be lined up with
a locking groove in the insert. Therefore, you will need to turn the
insert with a flat blade screwdriver a half turn or so until one of
the locking grooves in the insert comes around to the position of the
locking clip. Be sure that the locking clip is engaged into the locking
groove of the insert and not the fastener access slots. When the clip
engages properly you should hear a positive snap. Verify that the pin
is completely removed and that the insert does not rotate more that
5° in either direction using reasonable force. Proceed
around the cowling or panel repeating this process at all locations.
In some instances it may be necessary to press on the O.D. of the receptacle
to help the locking clip fully engage.
In the event that
the receptacle needs to be readjusted some time in the future, you
can reuse the original anti-lock pin if it is available or use the
MilSpec pick tool (MS-PK) or any thin pick tool and insert it into the unlocking
groove of the receptacle. Properly engaged, this will lift the locking
clip away from the insert enough to allow a flat blade screwdriver to
turn the insert in the appropriate direction. Note that there are two
locking grooves in the insert 180° apart. This allows adjustment in
.015" increments. Typical C-Spec (Camloc®) studs vary in length by .030"
so, with the MilSpec adjustable receptacles you can fine tune the fit
of your cowling or panel in increments of .015" (equal to 1/2 of a typical
stud length). After readjustment be sure to engage the locking clip
into one of the locking grooves in the insert.
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