PS Magazine - TB 43-PS-614
PS, The Preventative Maintenance Monthly
ISSUE 614
JANUARY 2004
Dear SGT Chamorro,
This smart idea adds another tool to a mechanic’s arsenal of
tools. Keep the ideas coming in.
PS 614
JAN 04
36
UH-60A/L…
Here are the plans a tool shop can use to make the tool.
The cost is around $22.
SGT Andres Chamorro, Jr
MA Army National Guard
Dear SFC Blade,
The Black Hawk’s bifilar expandable pins, NSN 5315-01-112-2991, are
tougher than nails to remove.
The procedure in paragraph 5-4-27 of TM 1-1520-237-23-3 makes
good sense. It tells you to hold the pin with a hex wrench to remove the
expandable nut, NSN 5310-00-923-4219.
However, when we try to remove the bifilar expandable pin with a crow’s-
foot wrench and a breaker bar or an open-end wrench, there’s only limited
space inside the bifilar to get a turn on the nut.
And when reinstalling the nut, we have trouble torquing the nuts to the
required 1,090 to 1,205 in-lbs using a crow’s-foot.
We solved the bifilar space problem by using a 1 1/16-in, 1/2-in drive hex
head deep well socket, NSN 5120-01-431-3859. We weld a piece of
0.375-in flat stock on top of the socket and drill a hole through the cen-
ter for the hex wrench. We also cut a 1/2-in square hole into the stock
for a breaker bar or a torque wrench.
Using this method brings the wrench out of the bifilar into the open area
to make it easier to remove and install the pin and properly torque the nut.
When torquing the nut, be sure the tool is at a right angle to the wrench.
That way, you don’t have to refigure the torque valve.
0.375
3.225
Ø1.435
01.063
0.500
2.938
2.000
1.500
0.500
0.500
0.500
0.500
Ø0.375
R0.938
Welded together;
socket centered on
3/8 diameter hole
in extension plate
Flatstock
Continuous
weld bead
Deep well
socket
Tool should look like this
after fabrication
Use breaker bar
and hex wrench
to remove pin
are you
ready to
try again?
yeah,
how ‘bout
gettin’ me
a hammer…
…this
expandable
pin is one
tough cookie
to get on
and off!
no need
for a
hammer.
use this
tool!
hold
on!
614. 36-37 (C)
11/24/03
2:44 PM
Page 1
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