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double-jack
[from its use in double-jacking, q.v.]
Mining
DCHP-1 (pre-1967)
Entry from the DCHP-1 (pre-1967)
This entry may contain outdated or offensive information, terms, and examples.
n.
a heavy long-handled sledgehammer.
Quotations
1944
double jack--an 8-pound striking hammer as used in hand drilling.
1961
The mechanization of mines in 1890--the replacing of hand-steel, single-jack and double-jack, by drilling machines--had created new problems and the mine owners had attempted to lower wages on the grounds that less skill and energy was required.