ok, guys, thanks one and all.

more info: tightwad here hoping to drill a .177 or .178 sized hole
without reaming to size, centered in end of a .250 OD piece of cold
rolled mild steel round, in my lathe (this will result in sort of
'thin wall pipe' of sorts) withOUT 'springing for' a reamer. mid-term
goal being to silver solder into this (drilled) hole the 'head' end of
a (for all practical purposes) round brass pilot jet, OD of jet .177
inch, or maybe two ten-thou's over that. final intent being, to place
a 'hex head' on other end of this same very short steel jet
'extension', to make it 'real world adjustable' (using a small
quarter-inch drive socket) WITHOUT having to 'spring for' the special
"single D" tool required, ordinarily, to turn (adjust) these same two
jets (one per carb). that tool's a 50-buck item...

note the existing 'head' of the 2 pilot jets are each 'recessed into'
a sort of 'bucket shaped depression' in their respective carbs (& said
'bucket' wall is approx .260 in diameter), making gripping the jets
with vicegrips (or anything similar, eg: needlenoses, pin vise, etc)
impossible. also tried cutting a 'straight slot' into one jet 'top'
for a normal screwdriver, but, due to dimensions _and_ tightness of
jets in carb body screwthreads, this was a 'poor choice'; reason being
it removed (broke off) half the 'existing tiny head' area. so I then
had to spend some nerve-wracking painful _hours_ of drilling jet
center out while it was 'in situ' IN the carb, using easy-outs,
penetrants, torch heat applications to carb body, etc....

truth be known, rather than silver solder, I'd prefer to taper the
shaft of the brass pilot jets slightly (quarter inch per foot), then
ream the 2 drilled holes (in the steel 'short hex head extensions')
with the 'correct' section of a (shortened) #2 taper pin reamer,
freeze the pilot, heat the 'new' steel pieces, and "shrink fit 'em"
on/over the brass pilot ends, but, alas, the tightwad factor still
applies & I got no correct-sized taper pin reamer here :-(

so, what's a poor boy ta'do?