Brief Description: Firewall trimming and rudder pulley bracket holes
I decided to make a drill jig to drill the rudder pulley bracket holes in the firewall (two sets of three holes each). I made this up from some .25 thick aluminum scraps. First I had to put my vise back on my mill drill and square it up, which takes a few minutes! I then measured the hole pattern on the plans template and transferred it to my aluminum scrap which I dye chem'd blue for marking with my calipers. Then I drilled the pattern on the mill. I actually made two jigs for some reason. All of this is completely unnessesary but it will insure that both left and right patterns are identical and I can use the jig to drill the rudder brackets at a later date and be assured a nice fit with very little fiddling. I rough trimmed the firewall so that it was more manageable. I then clamped the jig into position on the firewall and drilled the holes. I displaced the LH hole pattern up 0.6 inchers per plans change #47. I could not find my microstop to countersink the holes so I stopped there for the night. In the last picture you can see the four plus inches taller that the firewall needs to be to interface with the Melvilled cowling.
My annual is due on my flying airplane so I will have to lay off this project for a few weeks while I clear that maintenance!
Drill Jig clamped in place and two holes drilled, screws placed in drilled holes to help secure jig
RH pattern drilled (top of pic) LH layed out .6 inches above RH pattern.
Firewall rough trimmed, Upper Router pattern and two drill jig plates, all six holes drilled
