Green’s Dictionary of Slang

scrammy n.

[dial. scram, withered]

(Aus.) one who has a withered or defective hand or arm.

[Aus]Port Phillip Patriot 28 Oct. 2/5: Should the bantling have a ‘scrammy’ hand, he is the property of the contracted gentleman [AND].

In phrases

chuck a scrammy (v.)

to pretend to have a withered arm (so as to shirk work).

[Aus]Bulletin (Sydney) 21 May 14/1: A traveller who ‘chucked a scrammy’ (pretended to have paralysed arms) ‘had’ the sympathising shearers to the extent of £8.