Sherline 5000 Mill General Manual

DETERMINING DEPTH OF CUT
There are no firm rules other than common sense for determining depth of cut. A .030"
cut depth with a 3/16" end mill in aluminum could be considered light, but .003" cut
depth in steel with a 1/32" diameter end mill would break to cutter. Start with very light
cuts and gradually increase the depth until satisfactory results are achieved. Try to
develop the skill of knowing how much cut is satisfactory without breaking the cutter or
damaging the work.
Note that regular end mills should not be used for drilling; however, they may be
employed to enlarge an existing hole. The cutting edges deserve more respect than those
of drills even though similar in appearance; they are designed to cut with the sides.
WORK ACCURATELY
It should be remembered that a good machinist is capable of making a part to much closer
tolerances than those of the machine with which he is working. The accuracy of the parts
you make is limited only by your skill as a craftsman and the quality of your
measurement equipment. Accuracy should be the ultimate goal of every machinist!
CUTTING SPEEDS FOR MILLING
SPEED ADJUSTMENT FORMULA
SPINDLE RPM = (3.82 x S.F.M. ) ÷ D
S.F.M. = The rated Surface Feet for Milling. For drilling, use 60% of the rated
surface feet.
RPM = The rated spindle speed in Revolutions Per Minute
D = The diameter of work in inches
FIGURE 10-Formula for adjusting spindle speed for cutting a given diameter.
NOTE: To estimate RPM, remember that the speed range of your vertical mill is from 0
to 2800 RPM. (The lowest usable speed is about 70 RPM, so we use that in our
specifications. To obtain much more torque at the lower speed ranges, the drive belt can
be switched to the smaller diameter positions on the spindle and drive pulleys.)
Therefore, in the normal belt position, half speed is approximately 1450 RPM and so on.
You can estimate these speeds by a combination of the setting on the speed control knob
and the sound of the motor itself.