I suck at math so does anybody know what size drill is scale 1/48 37mm cannon bore for p-39 cannon?
37mm / 48 = .77
Go with a #104 or #105 to be be a bit under
EDIT #69! Small order of magnitude error [:P]
Cool site - http://www.custompartnet.com/drill-size-chart
If actual 1mm is scale 48mm, and actual .5mm is scale 24mm, .75mm is 36mm in 1/48 scale…
go here: http://www.scalemodelersworld.com/online-scale-converter-tool.html
and then go here: https://drillsandcutters.com/conversion-chart/
37mm = .77mm in 1/48th scale. Closest drill bit is just under 1/32 inch.
Thanks.
I realise the question is already answered, but here is a drill size chart for small drills.
FWIW, your math is 37 / 25.4 / 48 = .0303"
I use whatever I have and if it looks correct.
[dto:]
Ernie, oh Ernie…I can see I gotta send you and Carlos to obsessive/compulsive training. I teach the Anal Retentive class, right next door.
I already have enough of those traits, in and out of the hobby… close enough is my wild side…
And speaking of being obsessive, I noticed that “Ditto” is misspelled in FSM’s emoticon:
[dto:]
[:D]
How apropos! Unbelievable (and by the way, my excuse is my screen rez is too small to read it. That’s my story and I’m sticking with it). 
Lol Greg that’s a good one. I’ll flunk that class for sure [;)]