Hangar 9 Alpha.60 ARF Assembly Manual page 16

Section 6: Tail Installation
Step 5
Slide a #4 washer onto a 4-40 x 3/4" screw. Apply a
drop of threadlock to the screw. Prepare two screws
using this method.
16
Step 6
Secure the stabilizer using the two screws prepared
in the previous step.