Green’s Dictionary of Slang

1. (US) the teeth; thus modifed as pie-crunchers, potato-crunchers, etc.

1887		Springfield Dly Republic (OH) 8 Oct. 7/3: De good Lo’d want him fo’ to hab teef, an [...] he dun gib him de good ole crunchers.
1901		Bryan Morn. Eagle (TX) 17 Dec. 4/1: Roosevelt evidently intends to stand pat by Pat Garrett [...] to let the plsce-seelers of his own party howl until their pie-crunchers are flecked with the foam of impotent rage.
1901		Paducah Sun (KY) 17 Oct. 2/5: One gentleman [...] went off the other day in a hurry and left his false teeth on the bureau and we mailed the forgotten ‘crunchers’ to his address.
1914		Ogden Standard (UT) 15 Aug. 14/1: ‘They won’t gimmeachance’ piped love, inserting a smoked herring between his potato crunchers.
1916		Richmond Times Dispatch (VA) 2 July 48/5: [of a crocodile] Anything less than steel would be readily crushed by the animal’s powerful crunchers.
1925		G.H. Mullin Adventures of a Scholar Tramp 80: Afore he [a dog] kin snap ’is crunchers on ye, ye kin kick ’is hull jawr off.

2. (US) the feet.

1946

Mezzrow & Wolfe Really the Blues 100: Gee, you feel it way down to your crunchers.