uAvionix AV-30-E Installation Manual page 37

the surface. If the screw protrudes past the depth gauge the
screw is too long. Select a shorter screw or use standard
hardware shims/washers installed under the head of the screw
(not provided) to adjust the screw depth.
b. Perform step a. again, measuring the top right screw hole.
c. Hold the depth gauge behind the bottom left screw hole,
aligning the "B" hole on the depth gauge with the panel screw
hole. Again, if the screw protrudes past the depth gauge the
screw is too long. Select a shorter screw or use standard
hardware shims/washers installed under the head of the screw
(not provided) to adjust the screw depth.
d. Perform step c. again, measuring the bottom right screw hole.
Note that the lower two holes accommodate slightly longer
screws than the upper two holes, but the same process should
be used to achieve the greatest thread engagement.
2) Measurement: The permissible thread engagement in the top
mounting holes is 3.2mm. The permissible thread engagement in the
bottom mounting holes is 4.2mm. You can use digital calipers or
other accurate means to measure the length of the screw (every
screw is manufactured different), then measure your panel thickness.
Subtract the panel thickness from your screw length. If this length is
greater than 3.2 or 4.2 for each respective Top or Bottom location,
you will need to add washers when installing the screws. Repeat this
measurement of exposed threads with shims/washers on the screws
until you are under and within 0.5mm (0.020in) of the listed depths.
a. Screw thread length measured = 6.35mm (0.250in screw)
b. Panel thickness measured = 2.29mm (0.090in panel)
c. Thread engagement = 6.35 – 2.29 = 4.06mm
i. This screw may be used in the Bottom Mounting holes
UAV-1004234-001, AV-30-E Installation Manual
Rev H
since 4.06mm < 4.2mm, but NOT in the top mounting
holes as it is too long.
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