Drill Jigs Principles of Design Machinery ... - Evenfall Studios

EXAMPLES OF DRILL JIGS
the jig, the piece B, taking the thrust, would also turn, and being
threaded left-hand would thereby tighten the collar in the jig. Piece
H is a channel iron the function of which is to hold the jigs while re-
one of the jigs is placed upon the drill press
filling. In operation, .
table under each spindle between flat strips 7, which keep the jigs
from turning, at the same time leaving them free to be removed for
refilling. It will be seen that by having four jigs, and a three-spindle
machine, by timing them so that they will finish the holes one after
the other, it will give plenty of time to refill the fourth jig, and there-
by, with an extra drill or two kept sharpened by the tool grinder, the
Fig. 43. Jig for Drilling Collars
Machinery, N.r.
machine may be kept in constant operation. This machine is equipped
with a pump keeping a constant flow of cutting fluid on the drills. As
this machine is also handled by comparatively cheap labor, a saving
of almost 75 per cent was shown by actual test over methods previ-
ously employed in producing these collars on a turret lathe.
If ft were not possible to use four jigs at a time of the kind just de-
scribed, three being in operation, while one is in the hands of the
operator for removing the drilled piece and inserting a new one, there
would be one serious objection to the design of the jig shown. The
time required for unscrewing, and again tightening, the clamping col-
lar B, being threaded for its full length into body A, would be too long
to permit rapid work. Therefore, in a case where but one jig could
be used, the clamping device should be arranged so that the drilled
piece can be removed, and a new one clamped in place instantly. This
can be accomplished by some kind of a hinged or swinging cover, provided
with a threaded binder; one half turn of the binder would be
sufficient to clamp the work. In the case in hand, however, the sys-
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