The term whitesmith often times referred to a worker that polished or sharpened Iron to a bright finish.  The Oxford English Dictionary reads

a. A worker in ‘white iron’; a tinsmith. b. One who polishes or finishes metal goods, as distinguished from one who forges them; also, more widely, a worker in metals.

1302 in Cal. Pat. Rolls 50 John son of John le Whyte~smith. 1682 Lond. Gaz. No. 1735/4 Joseph Carles of Birmingham in the County of Warwick White-Smith, having..received several Edge-Tools to be mended. a1708 T. WARD Eng. Ref. III. (1710) 2 For not a White-Smith nor a Black, Could frame such things as he would lack. 1778 Eng. Gazetteer (ed. 2), Swindon, Staff...is one of those places which have blade-mills, where scythes, axes, reaping-hooks, &c. after being prepared for it by the white-smiths, are ground to a fine edge. 1826 SCOTT Provinc. Antiq. 104 He was a white-smith, and published various lucubrations under the title of the Tinclarian Doctor. 1833 [see below]. 1866 ROGERS Agric. & Prices I. xxiii. 603 The brass was sometimes served out to the whitesmith to be manufactured. 1886 FENN Patience Wins xii, I arn't a blacksmith, I'm a whitesmith, and work in steel.

So now when we look at 18th and 19th century documents we have to ask ourselves what did they really mean