User Manual

16
CUTTING SPEEDS
The type of material to be drilled, its hardness and thickness will all greatly affect the recommended cutting
speed. See the chart below for general guidelines for cutting speeds. Use the formula to determine the
recommended RPM for the diameter of annular cutter being used:
RECOMMENDED SURFACE SPEEDS
Note: work materials which have been flame cut will be heat treated in the affected area. These areas
will require much slower cutting speeds.
Work Material Surface Speed MPM (m/min)
Aluminum 60-90
Brass 40-50
Soft Cast Iron 30-50
Hard Cast Iron 15-21
Mild Steel 24-30
High Tensile Steel 6~13
Stainless Steel 3~5
RPM = 318.5 x MPM / cutter diameter (in mm)
For example: if you are drilling mild steel with a 50mm cutter, the recommended MPM would be about 30 m/
min, so the ideal RPM would be:
318.5 x 30/50 =191/min
But if you were drilling high tensile steel, the MPM would be about 6 m/min, so the ideal RPM would be: 318.5 x
6/50 =38/min
REVERSING SWITCH
Select desired direction of rotation. This switch has 3 positions:
up is forward, middle is neutral, and down is reverse rotation.
WARNING: If the motor is switched on with the direction switch in the
neutral position, the machine will not turn but will be “live”, as soon as either
forward or reverse is selected, the arbor will begin turning! Take due care to
avoid surprises. This in NOT the proper order of operations. Proper order of
operations for normal drilling (not tapping) is as follows: magnet: on.
direction: forward. motor: on. motor: off. magnet: off.