Baileigh Industrial DP-1375VS-110, Operator'S Manual

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DRILLING RECOMMENDATIONS
Drilling Speeds
The speed of a drill is usually measured in terms of the rate at which the outer periphery of the
tool moves in relation to the work being drilled. The common term for this is Surface Feet per
Minute (SFM).
The relationship of SFM is expressed in the following formulas:
•
SFM = 0.26 X rpm X Drill Diameter (in inches)
•
RPM = 3.8 x SFM
÷
Drill diameter (in inches)
In general, the higher the speed the shorter the drill life. Operating at the low end of the speed
range for a particular material will result in longer life.
The most efficient speed for drill operation depends upon many variables:
•
Composition and hardness of material.
•
Depth of hole.
•
Efficiency of cutting fluid.
•
Type and condition of drilling machine.
•
Desired quality of hole.
•
Difficulty of set-up.
Drilling Feed
The feed of a drill is governed by size of tool and the material drilled. Because feed rate partially
determines rate of production and also is a factor in tool life, it should be chosen carefully for
each job. In general, the most effective feeds will be found in the following ranges:
Diameter of Drill (inches) Feed per Revolution (inches)
Under 1/8 0.001 to 0.002
1/8 to 1/4 0.002 to 0.004
1/4 to 1/2 0.004 to 0.007
1/2 to 5/8 0.007 to 0.015
Excessive Speed/Feed Indicators
•
A drill that splits up the web is evidence of too much feed or insufficient tip clearance at the
center because of improper grinding.
•
The rapid wearing away of the extreme outer corners of cutting edges indicates that speed is
too high.
•
A drill chipping or breaking out at the cutting edges indicates that either feed is too heavy, or
drill has been ground with too much tip clearance.