ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL
Rev.
6
MM-2-19
Apr
7/15
Table 2-10. Pipe Plugs
NOTE
When threading bolts into engine housings, refer to the applicable engine
manual for standard torque limits.
Thread Size
(inches)
Torque Limits (inch-pounds)
Min Max
1/16-27 NPT
30
40
1/8-27 NPT
30
40
1/4-18 NPT
70
85
3/8-18 NPT
95
110
1/2-14 NPT
140
160
3/4-14 NPT
210
230
1 NPT
285
315
1-1/4 NPT
355
385
Table 2-11. Crush Type Gaskets
NOTE
Turn the part until the sealing surfaces are in contact and then tighten to the
angle of turn listed for the appropriate thread size.
Thread Pitch On
Part to be
Tightened
(Threads per Inch)
Angle of Turn
Aluminum
Copper
8 135°
67°
10 135°
67°
12 180°
90°
14 180°
90°
16 270°
135°
18 270°
135°
20 270°
135°
24 360°
180°
28 360°
180°
Table 2-12. Minimum Prevailing Torque Values for Re-used Self-Locking Nuts
FINE THREAD SERIES
COARSE THREAD SERIES
Thread Size
(inches)
Minimum Prevailing Torque
(in-lbs)
Thread Size
(inches)
Minimum Prevailing Torque
(in-lbs)
7/16-20 8 7/16-14 8
1/2-20
10 1/2-13 10
9/16-18
13 9/16-12 14
5/8-18
18 5/8-11 20
3/4-16
27 3/4-10 27
7/8-14
40 7/8-9 40
1-14 55 1-8 51
1-1/8-12 73 1-1/8-8 68
1-1/4-12 94 1-1/4-8 88
UNCONTROLLED COPY WHEN DOWNLOADED OR PRINTED
Visit www.enstromhelicopter.com for instructions to order an original manual and to register for email notification of updates.