Sunday, October 19, 2014

C-1203B Angles Drilled & AP Servo Pushrods Fabricated

After verifying both C-1203B aft attach angles were bent to 90 degrees, the same procedure was used again to drill both. One angle was marked and center punched then both C-1203B aft attach angles were clamped back to back and a tiny lead holes were drilled then enlarged to #40.
Clamping both C-1203B aft attach angles back to back for simultaneous drilling.
Both the C-1203B aft attach angles were clamped back to back and drilled to #40.
Both the C-1203B aft attach angles after being drilled to #40.

Fortunately, I remembered seeing another pushrod tube in a bag of autopilot servo parts which will also need priming … so went ahead in the plans to investigate. The tube is used to fabricate two pushrods for the autopilot servos. The F-1291 roll servo pushrod is cut to 3 1/2" and the F-1292 pitch servo pushrod is cut to 4 1/2". As with the control stick pushrods, the tubes are drilled to #3 at both ends and tapped to 1/4-28 threads. Figured may as well go ahead and fabricate the autopilot servo pushrods now while the shop is set up for making pushrods so they can get airbrushed with primer as well.
The F-1291 and F-1292 autopilot roll and pitch servo push rods after being cut to the proper length.

When drilling the F-1291 and F-1292 servo push rods, the same method was used as covered in the previous post using one layer of duct tape placed over the tubing prior to clamping in the V blocks and using the drill press to drill out the tubing at both ends to #3. If you have a lathe it is the tool of choice here.

While tapping the F-1291 and F-1292 push rods … to prevent twisting in the vice, some duct tape was wrapped around the tube and a small vice grip was used to prevent the tube from twisting.
Tapping the F-1292 autopilot pitch servo pushrod to 1/4-28 threads. Duct tape under the small vice grip prevented scoring and the vice grip prevented the tube from twisting in the vice.

Now that there are a bunch of small parts to prime, am hoping the weather cooperates long enough to break out the airbrush and spray some primer. We have had rain and high winds the last couple of days plus the daily high temps here are at or slightly below the minimum recommended temperatures for the Akzo primer. To get around the temperature issue, am planning on using a large cardboard box and placing a light bulb inside to generate some heat while the primer cures.