Green’s Dictionary of Slang

(Aus.) to shear incompetently; thus tomahawking n.

1859		H. Kingsley Recollections of G. Hamlyn (1891) 159: Shearers were very scarce, and the poor sheep got fearfully ‘tomahawked’ by the new hands, who had been a very short time from the barracks.
1872		E. Eden My Wife and I in Queensland 96: Some men never get the better of this habit, but ‘tomahawk’ as badly after years of practice as when they first began.
1895		‘Banjo’ Paterson ‘Those Names’ in Man from Snowy River (1902) 162: The ‘ringer’ that shore a hundred, as they never were shorn before, / And the novice who toiling bravely, had tommyhawked half a score.
1897		Worker (Brisbane) 4 Sept. 8/3: He ‘shaves’ his sheep, or ‘pinks ’em’ when he shears them nice and clean, / But mostly ‘roughs’ and ‘tomahawks,’ with ‘second-cuts’ between.
1900–10		Stephens & O’Brien Materials for a Dict. of Aus. Sl. [unpub. ms.] 159: A bad shearer will tomahawk his sheep, i.e. cut them irregularly, leaving steps and ridges of wool on the sheep, appearing as if the fleece had been chopped off.
1911		E.S. Sorenson ‘Shearer and Rouseabout’ in Life in the Aus. Backblocks 241: In most sheds where pinking is desirable the ringer, no matter how good or fast he may be, is restricted to a certain limit, and no one is allowed to go beyond him. This prevents tomahawkings.
1945		Baker Aus. Lang. 63: Tomahawk, to shear roughly and gash a sheep.