Now I used the 3/16" bit at an angle and moved it around the radius while turning the drill bit to remove a little more material.
Then I used the small 13/64" bit and turned it by hand about 6 times from each side to square off the edges of the hole.
Then I used a round KS needle file to take out the little bit left in the center.
Take your time until the 13/64" drill bit turns with just a little resistance in the hole. Then hit it with the round file just a little to get that micro little bit past 13/64" to get to 5.2mm.
I sure wish there was a 12" long 5.2mm drill bit.