Hi Gang, FWIW
Solid carbide drill bits are available in the US in English sizes from
1/64 to 1/4" in 1/64" increments. They’re generally refered to as
circut board drills They’re primarily used in the electronics industry
to drill small holes in printed circut boards. Many boards are made
with a high fiber glass content. The fiber glass wears out high speed
steel drills very fast, carbide lasts a little longer.
Metric siszes are available in .05 mm increments from .35 mm - 3.15
mm. Other’s amy be available on special order. Prices vary according
to size, but generally run about $5.00/ bit in quantities of 1.
Ordereing 10 or more usually results in about a 10% discount.
Some times tool companies like Harbor Freight have 'resharpened’
carbide bits at considerable savings. These are ones the electronics
folks have used & then sold as scrap; they don’t like to resharpen
them for their application.