Wen 4212 Manual page 19

OPERATION
ASSEMBLY & ADJUSTMENTS
ADJUST THE DRILLING DEPTH (FIG. 19)
1. Loosen the depth scale knob and turn the depth scale ring to
the desired depth.
2. Lock the scale ring in place by tightening the depth knob.
This will stop the bit once it reaches a certain depth.
Fig. 20
DRILLING SPEEDS
NOTE: View Drill Bit Size Recommendations on page 20 for
general guidelines.
There are a few important factors to keep in mind when
determining the best drilling speed:
• Material type
• Hole size
• Drill bit or cutter type
• Quality desired
Smaller drill bits require greater speed than larger drill bits. Softer materials require greater speed than
harder materials. See page 19 for recommended speeds for particular materials.
DRILLING METAL
• Use metal-piercing twist drill bits.
• It is always necessary to lubricate the tip of the drill with oil to prevent overheating of the drill bit.
• All metal workpieces should be clamped down securely. Any tilting, twisting, or shifting causes a rough
drill hole, and increases the potential of drill bit breakage.
• Never hold a metal workpiece with your bare hands. The cutting edge of the drill bit may seize the
workpiece and throw it, causing serious injury.
• If the metal is flat, clamp a piece of wood under it to prevent turning. If it cannot be laid flat on the table,
then it should be blocked and clamped.
DRILLING WOOD
• Brad point bits are preferred. Metal piercing twist bits may be used on wood.
• Do not use auger bits. Auger bits turn so rapidly that they can lift the workpiece off of the table and whirl
it around.
• Always protect the drill bit by positioning the table so that the drill bit will enter the center hole when
drilling through the workpiece.
• To prevent splintering, feed the drill bit slowly right as the bit is about to cut through to the backside of
the workpiece.
• To reduce splintering and protect the point of the bit, use scrap wood as a backing or a base block under
the workpiece.
19