Snarl \Snarl\, v. t. [imp. & p. p. Snarled; p. pr. & vvb. n. Snarling.]

[Etymol. uncertain.]

To form raised work upon the outer surface of (thin metal ware) by the repercussion of a snarling iron upon the inner surface.

Source: Webster's Revised Unabridged Dictionary (1913)
 

Snarling \Snarl"ing\, a. & n. from Snarl, v.

Snarling iron, a tool with a long beak, used in the process of snarling. When one end is held in a vise, and the shank is struck with a hammer, the repercussion of the other end, or beak, within the article worked upon gives the requisite blow for producing raised work. See 1st Snarl.

Source: Webster's Revised Unabridged Dictionary (1913)