Karl Townsend fired this volley in
:

have you heard of the Devlieg microbore line?
http://tinyurl.com/79g7e25

Karl,

I can't even imagine how an adjustable boring bar would help in this
case. I have an adjustable boring head of the off-set slide type.

But insert-style (indexable carbide, and not) internal threading tools
are a LOT cheaper, and in this case, more flexible than that... those
cartridges are outrageously expensive.

The grinding of a healthy relief on the bottom is important, but more
important would be grinding the angle to less than 60-degrees to make up
for cutting on the lag and lead.

A single-point threading mill would give its best profile when as small a
cutter radius as possible, commensurate with enough stiffness and thread
depth.

LLoyd