Green’s Dictionary of Slang

1. (Aus./N.Z.) a sixpence [= zac n.].

1952		Argus (Melbourne) 13 June 4s/3: Here we have the ‘John Dillon’, and [...] ‘hammer and tack’ for ‘zac’ (6d.) and ‘Rhodes scholar’ for ‘dollar’ (5/-).
2002		Pete’s Aussie Sl. Home Page 🌐 hammer and tack: a zac, sixpence (obs.).

2. (Aus.) a road [= SE track].

1972		Dodson & Saczek Dict. of Cockney Rhy. Sl.
1984		Partridge DSUE (8th edn) 524: A track [...] since ca. 1920.

3. (Aus./US, also hammer and rack) the human back.

1935		A.J. Pollock Und. Speaks.
1943		Baker ‘Influence of American Sl. on Australia’ in AS XVIII:4 256: There’s two Jacks on me hammer.
1963		L.F. Freed Crime in S. Afr. 106: His ‘hammer and rack’ [is] his back.
1967		‘Whisper All Aussie Dict.’ in Kings Cross Whisper (Sydney) xxxv 6/2: hammer and tack: Back.
1972		J. McNeill Old Familiar Juice (1973) 75: dadda: (heaving a sigh) Whew! The screw’s right on me hammer.
1983		J. Byrell (con. 1959) Up the Cross 10: ‘[He] crept up behind Awful’s hammer and whacked Awful on the gregory’.
1983		R. Aven-Bray Ridgey-Didge Oz Jack Lang 31: Hammer and Tack Back.
1996		J. Byrell Lairs, Urgers & Coat-Tuggers 161: Gloaming sat right on Beauford’s hammer and bunged on the pressure just before the turn into the straight.
1999		E. Bunker Mr Blue 114: A ‘bottle and stopper on the hammer and tack,’ means there’s a copper on your back.
2002		D. Shaw ‘Dead Beard’ at www.asstr.org 🌐 My strife grins and nods towards Dionne’s hammer and tack, then waves me forward.
2016		N. Cummins Adventures of the Honey Badger [ebook] I knew Kurtley Beale was on my hammer.

4. (Aus.) dismissal from a job [= sack n. (2a)].

1983

R. Aven-Bray Ridgey-Didge Oz Jack Lang 31: Hammer and Tack [...] sack (fired from the job).

5. (Aus./N.Z.drugs, also hammer and jack, tack) heroin [= smack n.² (1)].

1982		G. Newbold Big Huey 217: Chris [...] was doing eight for importing coke and hammer.
1990		Tupper & Wortley Aus. Prison Sl. Gloss. 🌐 Hammer and jack. Heroin. Rhyming slang for ‘smack’. Sometimes just hammer.
1993		Smith & Noble Neddy (1998) 264: I evened the score 10 times over in the near future by leaving them out of three rip-offs that I did for more than six million dollars worth of hammer [heroin].
1996		(con. 1964-65) B. Thorpe Sex and Thugs and Rock ’n’ Roll 328: ‘They was [...] inta the hammer ’n’ tac long before’.
1997		L. Davies Candy 4: What I get from hammer is a kind of deep comfort.
2001		D. Looser Boobslang [U. Canterbury D.Phil. thesis] 83/2: hammer n. heroin [...] hammer and tack n. heroin (and the outfit that goes with it: hypodermic syringe, etc [...] 184/1: tack n. heroin.
2012		D. Whish-Wilson ‘In Savage Freedom’ in Crime Factory: Hard Labour [ebook] ‘You need water?’ ‘I need Hammer.’ ‘None left’.
2012		‘Dutch’ ? (Pronounced Que) [ebook] He and Shameeq took their hammer game to the next level.