Elevator Hinges

This blog covers modification to the elevator hinges

Overview
As mention in a previous blog don't drop the aluminum inserts supplied with the kit - I never found the one I dropped but no issue, have one machined.

As small things all take time and a new bush was eventually machined with a 3/16'' bore, however it was discovered that the bore of the factory bushes was 5 mm and checking at the hangar revealed the machinist was correct. At this point the elevator was removed and all the stab hinge points drilled out to 5 mm.

Aircraft Spruce
Part #05-2500

While all the parts were disassembled it was decided to lubricate the spherical bearings with 3 : 1 oil, then pack with grease and to protect them from dirt ingress, aluminium bush's Seal-Its were ordered from Aircraft Spruce.

Each aluminium bush's flange was step machined to create 0.63'' dia x 0.025'' deep lip with the seal fixed over that lip using Loctite Black Max ACC and set aside to cure. 

Spherical bush rotated to allow oil and grease to be added

Parts ready to reinstall

Note: Each seals lip is packed with grease at installation.

Elevator hinges installed ready to remount

Note: Bolt thread will be trimmed to match AN3 bolt

Installation
Starting at the starboard side with the elevator level the hinge with seal was inserted into the stab brackets the a M4 screw slipped through to secure the assembly. The next one was inserted by springing the stab hinge with a soft podgy and inserting the next hinge and seal. 

This was repeated until reaching the port side when the first M5 Unbrako cap head screw was fitted. This proved to be a task as it had to be done using two fingers only in a small opening.

With all the bolts installed they were secured with M5 nylock using a shortened hex key and spanner.

Comment
It would be best to use AN hardware and the factory has been notified of the issue.

If installing seals again the bushes would be machined from mild steel with the step for the seal machined in one operation. It proved to be very difficult to center the very fine step required on the existing bushes.

The lubricated bearings were noticeably smoother and the seals will help keep out grit.