Having match drilled the horns for the pushrod initially with a #40 drill, I needed to decide in what order to final drill the holes. ie either …
- Final drill one horn, then use the hardwood block again to match drill the other horn with the final drill size.
- Just final drill both horns individually
I decided on option *1, and it worked very well. I used a length of timber on top to check everything was parallel to the rear spar in all planes. Once again this required several attempts at drilling a hole through the little hardwood block at the required angle.
As previously discussed, I had decided to final drill to 4.7mm, then use a 3/16″ reamer for the final size. This worked well too, with the AN3 bolts being an exact fit.
Proof of the pudding!
Of course the moment of truth was to trial fit the pushrod connector, nip it up, then peep at the mass balances to see if they were perfectly parallel. Happy days, all was well!