Dave's Sonex Builders Log

Today I spent some time completing the countersinks for the motor mount fasteners. I was careful to clamp each set of holes and left the shims and motor mount in place. The shims and the clamps helped keep things from moving so I could get nice countersinks. After completing the countersinks I up drilled the holes to 1/4 inch for the fasteners. I had sized the fasteners to get the correct grip but I discovered that the fasteners for the two bottom holes were actually too long and interfered with the tubes for the gear legs. I’ll have to pick a new fastener length for these.

I started to counter sink the motor mount angles on the fuselage but I damaged the first one I drilled. So, I made a new left hand upper motor mount bracket today. I guess this is why they bolt in.

Today I worked on up drilling the holes for the motor mount to 3/16 inch. I intend to use my 3/16 inch pilot 100 degree countersink in my microstop to countersink the holes then I’ll up drill to 1/4"

I worked on making engine mount shims today. I started with 0.060 inch shims but these proved to be too thin. I probably should have measured first. Next I made up two 0.090 inch shims. These seem to work fairly well at the bottom and it looks like I need the same for the top.