The importance of correct torque application cannot be overemphasized.
Undertorque can result in unnecessary wear of nuts and bolts, as well as the parts they secure. Overtorque can
cause failure of a bolt or nut from over-stressing the threaded areas. Uneven or additional loads that are
applied to the assembly may result in wear or premature failure. The following are a few simple, but
important procedures, that should be followed to ensure that correct torque is applied.
Be sure that the torque applied is for the size of the bolt shank not the wrench size.
Use a calibrated torque wrench.
Be sure the bolt and nut threads are clean and dry.
Apply a smooth even pull when applying torque pressure.
Whenever possible torque the nut, not the bolt.
When applying torque to a bolt be sure to have a washer under the bolt head and lubricate the bolt shank.
The chart below is for most of the fasteners used on RV’s. Note that on the smaller bolts the torque
is quite low and is in inch pounds. Do not try and use a foot pound torque wrench on these bolts.
Get one calibrated in inch pounds.
The propeller manufacturer and the engine manufacturer have specific torque requirements for their equipment.
Consult the appropriate manual for that information.
| AN Bolt size
|
Bolt size - Threads per inch
|
Standard nuts AN3IO, AN315,AN365
|
|
|
|
INCH Pounds
|
FOOT Pounds
|
| AN3
|
#10-32
|
20-25
|
1.6-2.0
|
| AN4
|
1/4-28
|
50-70
|
4.2-5.8
|
| AN5
|
5/16-24
|
100-140
|
8.3-11.6
|
| AN6
|
3/8-24
|
160-190
|
13.3-15.8
|
| AN7
|
7/16-20
|
450-500
|
37.5-41.7
|
| AN8
|
1/2-20
|
480-690
|
40.0-57.5
|
| AN9
|
9/16-18
|
800-1000
|
66.6-83.3
|
| AN1O
|
5/8-18
|
1100-1500
|
91.6-125.0
|
|
|
|
|
