nuts-and-bolts, adj.¹ — Green’s Dictionary of Slang

nuts-and-bolts adj.¹

also bolts-and-nuts

(US) crazy, insane.

1931–4		D. Clemmer Prison Community (1940) 334/1: nuts and bolts, adj. Looney, feebleminded.
1949		Monteleone Criminal Sl. (rev. edn).
1960		J. Franklyn Dict. of Rhy. Sl. 40/2: bolts and nuts Silly, mentally deficient, or lunatic [...] generally cut to bolts only. ‘He’s bolts!’ means he’s nuts (c. 1920).