Delta 11-985 - Manual (Page 14)

14
BORING IN WOOD
Twist drills, although intended for metal drilling, may also be used for boring holes in wood. However, machine spur
bits are generally preferred for working in wood; they cut a square bottom hole and are designed for removal of wood
chips. Do not use hand bits which have a screw tip; at drill press speeds they turn into the wood so rapidly as to lift
the work off the table and whirl it.
For through boring, line up the table so that the bit will enter the center hole to avoid damage. Scribe a vertical line on
the front of the column and a matchmark on the table bracket, so that the table can be clamped in the center position
at any height.
Feed slowly when the bit is about to cut through the wood to prevent splintering the bottom face. Use a scrap piece
of wood for a base block under the work; this helps to reduce splintering and protects the point of the bit.
DRILLING METAL
Use clamps to hold the work when drilling in metal. The work should never be held in the bare hand; the lips of the drill
may seize the work at any time, especially when breaking through the stock. If the piece is whirled out of the operator's
hand, he may be injured. In any case, the drill will be broken when the work strikes the column.
The work must be clamped firmly while drilling; any tilting, twisting or shifting results not only in a rough hole, but also
increases drill breakage. For flat work, lay the piece on a wooden base and clamp it firmly down against the table to
prevent it from turning. If the piece is of irregular shape and cannot be laid flat on the table, it should be securely
blocked and clamped.