American Slang (The Times, Friday, 8 May, 1931, page 12, col. E):
“A ukulele, besides its musical meaning, may be a drum of bullets to be fitted to a “typewriter” — the Thompson Machine Gun (the “Typewriter” link is not for the faint-hearted).
[For a real ukulele and typewriter combo, see this].
According to The Times, Friday, 30 October, 1970, page 15, col. A, the driver of London Cab 3899 might have given you a
‘quick burst of “Please don’t talk about me when you’re gone” on his ukulele while you wait at the traffic lights.’