E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Knuckle-duster.
A metal instrument which is fitted to a mans fist, and may be readily used in self-defence by striking a blow. Sometimes these instruments are armed with spikes. It was an American invention, and was used in England in defence against the infamous attacks of Spring-heel Jack. We have the phrase To dust your jacket for you, meaning to beat you, as men dust carpets by beating them.