On Feb 15, 8:23*pm, "RogerN" wrote:
I'm getting close to start cutting metal on the AR-15 receiver forging. *The
first holes will be for the pins that join the upper and lower receivers. *I
have the .251 reamer, I'm considering spotting with a 1/4" end mill, center
drill, drill 5/32, drill with 3/16 end mill, drill 15/64, then ream to
.251". *I'm thinking that drilling with the 3/16 end mill will position the
hole in line with the spindle, if a single point tool would be better, I
could grind a 3/16 end mill to a single point boring bar. *Would this
process get the hole positioned about as a good as possible without jig
boring or grinding? *Would spot drilling, drilling, and reaming be just as
good? *Any better ideas?

Thanks!

RogerN

They do make machining and drilling jigs for the AR home machiners.
You'll need something like that to get the buffer tube threads square
with the world. Some guys had them to rent, too.

Stan