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A review of the MS hinge spec. (attached) reveals an allowable ID
tolerance of 0.005" for the hinges we are using. Given this range, no
single pin size can produce a good fit for all allowable hinge IDs. A
pin sized to just barely fit a hinge at the low end of the tolerance
range will have a lot of slop in a hinge at the high end of the
tolerance range. The standard MS hinge pin adds to the problem in that
it allows a large clearance, even for a hinge manufactured at the low
end of the tolerance range. When you stack all the tolerances you end
up with copious amounts of play. As the OD of the pin and the ID of the
hinge spread, local stresses rise, wear rates climb very rapidly and, in
a vibration environment, the hinge gets hammered by the mass of whatever
is attached to the other side. As you approach a perfect line to line
fit, loads are distributed and the relative motion between the hinge
halves vanishes, eliminating the hammering.
The MS20001, as spec'd out, is simply poorly suited for applications
where a close tolerance hinge is desired.
Chris Zavatson
N91CZ
360 std
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