Green’s Dictionary of Slang

1. (orig. US) a typewriter.

1931		E. Hemingway letter c.1–12 Nov. in Baker Sel. Letters (1981) 344: This damned typer skips like a stammering flannel mouth nigger.
1939		V. Davis Gentlemen of the Broad Arrows 252: If you’ll let me use a typer [...] I will do it now.
1957		J. Blake letter 30 Aug. in Joint (1972) 105: The typer arrived a week ago.
1967–8		C. Bukowski Notes of a Dirty Old Man (1973) 12: The suitcase in the left hand, the portable steel typer in the right.
1972		C. Bukowski Erections, Ejaculations etc. 388: I sit down, stick the sheet of paper in the typer, open a beer.

2. (US Und.) a machinegun.

1931		G. Milburn ‘Convicts’ Jargon’ in AS VI:6 441: typer, n. A machine gun.
1949		Monteleone Criminal Sl. (rev. edn).