Here is the drill jig it is 3/4 inch angle welded to a .9 x .9 inch block. The hole is centered on the angle and is .450 to center line from the edge. The hole is .5 inch and fit the drill bushings from the aviation tool store. the hole was made large enough to allow you to slide the drill bushings in. You could try to make it a bit smaller and cut threads to hold the bushing securly, but this worked beautifully. The idea is to band clamp it to the pipe I used my first drill bushing at #30 and did a few turns to make sure I was centered on my markings for hold location then locked the band clamp down. From there it is slow as you can with lots of cutting oil. I used 4 steps in the drill bushing then the last two steps were following the hole I had. The bushing holder was still a good reference when drilling free hand. I could get one 5/16 hole in before my drill got to hot to hold I now respect the hardened steel. This worked good on the nose main gear and drilling your brake flange. It dosent fit well on the front gear socket I'll have to figure that one out later. Right now I am thinking that grinding away some of the angle will provide clearance.
a band clamp is used on the "Stem" to secure it to the pipe your drilling