knobble

[nob-uh l] /ˈnɒb əl/
verb (used with object), knobbled, knobbling.
1.
to knob (excess stone).
2.
Metallurgy. to treat (semirefined puddled iron) on a hearth before shingling to produce wrought iron.
Origin
1835-45; knob + -le
Related forms
knobbler
[nob-ler] /ˈnɒb lər/ (Show IPA),
noun