With the soldering on the APM2 complete (I think) it was time to move on with the stack up plates for the quad. For those who have not put their hand on an APM2, the Xacto knife with #11 blade provides some scale.
I am using aircraft plywood (it is on hand and paid for) rather than the FRP/G10 that is popular. Using ancient methods of razor saw and ruler, three stack up plates were cut and the process of making a home for the APM2 was initiated.
Some tolerance creep has set in but that is normal with a mixture of hand and machine tools. I wanted the wiring to pass up through some of the boards rather than outside the stack. This may provide a neater harness and offer some protection against impact damage.
Having a Mini Mill comes in handy on a project like this. The cable slot was a cinch to cut after penciling an outline. I used a 1/8 4 flute end mill to do the cutting. Sandpaper was used to finish the edges.
I marked the APM2 holes, drilled them, and then counter drilled with a 1/4 end mill to sink the nylon standoffs into the plywood. This reduced the length of the mounting screw needed to hold the board in place.
After turning down (with my 7 x 12 lathe) some aluminum threaded hex standoffs to clear the electrical parts on the board, I cut a plexiglass plate to cover the APM2, drilled it, and found appropriate screws to hold the lid on. The 4/40 screw heads are on the bottom of the plywood plate. They pass up through the nylon spacers, through the APM2 with the pcb held down by the turned end of the aluminum standoffs. I colored the hex end 'knobs' black with a Sharpie to add some style to the mount.
Here is a idea: Perhaps using plywood will dampen vibrations in the system? I can also employ some RTV/Silicone washers if vibration is more suspect. Frankly a proper balancing of propellors would go a long way to reducing vibration on a quadrotor.
Next task: The stack plate for the Spektrum RC gear (main and remote). I actually cut/drilled three plates prior to the APM2 final machining. I've got two blanks to go.