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1,328,07
10 and 14 become broken off, the sleeve 6
will still secure the bit against detachment
from the shank 2, so that there will be no
liability of said bit becoming lost in the
s bore.
Water passageways 16, 16 are provided
down through the shank 2, and through the
head 4 and shank 9 of-the bit, through which
water flows from the interior of a drill stem
10 to the cutting points of the bit so as to flush
the bore and carry away the cuttings from
the bit.
What I claim is:-
The combination with a drill shank
15 having a mortise, of a bit, provided with a
tenon, fitted into said mortise, said bit
having opposing vertical grooves and said
shank being provided with lateral mortises
alined with said grooves, detachable blades
fitted into said grooves and whose upper 20
ends are formed into tenons which fit into
said alined mortises, and a sleeve fitted
over said shank and secured onto said bit,
said sleeve locking said tenons in their re-
spective mortises. 25
In testimony whereof I have signed my
name to this specification in the presence of
two subscribing witnesses.
GRANVILLE A. HUMASON.
Witnesses:
E.- V. HAROWAY,
E. B. BIERCE.