Sherline 5000 Mill Assembly Instructions

FIGURE 22—Directions of Feed and Cut showing (A)
Turning work between centers and (B) Facing off a
work piece
CUT
CUT
FEED
FEED
A
B
-17-
lever is standard on all non-CNC-ready mills and vertical
milling columns as of that date. This lever is located on the
Z-axis leadscrew behind the saddle. When turned to the
full clockwise position the saddle will move freely. A spring-
loaded ball locates in a detent in the bottom of the lever to
hold it in this position. To lock the saddle in position, move
the lever to the full counterclockwise position. This locks
the lever against the saddle nut which prevents the
leadscrew from turning. The exploded view on page 43
shows the location of the components.
Engineering compromises
I'm always at odds with myself when I write instructions
on complicated procedures like describing the alignment
procedure for this mill. By giving you this much information
I know that I am making life easier for some customers by
answering their questions. At the same time I am probably
confusing another customer who would never have asked
the question because of the type of work that the mill or
lathe is being used for. I don't want to create a customer
who spends all his time trying to achieve perfect alignment
for work that doesn't require it and ends up never using the
machine. Engineering is always a compromise. I deal with
this fact with each new product that I design. While our
machines aren't accurate enough for some customers, they
are still too expensive for others. I hope you are pleased
with the new capabilities this multi-direction mill can bring
to your shop. I think you will find the combination of features
offers a very good machining value.
USE OF CUTTING OILS AND LUBRICANTS
Much can be written about the use of lubricants, but they
may usually be dispensed with where production rates are
not very important. A small amount of any kind of oil applied
with a small brush will be sufficient. Aluminum and its alloys
may require the use of cutting oil to prevent the chips from
welding to the tool’s point. Do not use oils with a low flash
point or a bad smell. If desired, a mixture of one part soluble
oil to six parts water may be used on steel to assist in
producing a smoother finish and reduce tool chatter when
parting off. Brass and cast iron are always turned dry.
Cutting lubricants should be cleaned off the tools after use.
Cutting oils can be purchased at an industrial supply store.
In the past it was sold only in “industrial” quantities that
were too large for home shop use; however, several industrial
suppliers now sell it in quantities small enough to be practical
for the home machinist. Do not use high sulfur pipe thread
cutting oil. It is good for hard-to-machine materials, but is
so dirty to work with we do not recommend it. We also find
some of the cutting fluids used for tapping are too smelly
and unpleasant to use for general machining.
The main purpose of using lubricants is to keep the chips
from sticking to the cutting tool. When used properly, modern
high-speed tool bits are not likely to be affected by heat on
the type of work usually done on miniature machine tools.
GENERAL MACHINING TERMS
Two terms frequently used in machining are “feed” and
“cut.” Reference to the diagrams that follow will show
what is meant by these terms. Normal turning on a lathe,
when used to reduce the diameter of a work piece, involves
advancing the cutting tool perpendicular to the lathe bed by
an appropriate amount (depth of cut) and feeding the tool
along parallel to the lathe bed to remove material over the
desired length. (See Figure 22.)
CUT (Z-AXIS)
FEED (X-AXIS)
FEED (Y-AXIS)
GENERAL RULES FOR FEED RATES AND CUTTING SPEEDS
Before attempting to machine any metal, please try to
remember this simple rule about machining:
“If the tool chatters,
decrease speed and increase feed.”
Understanding this simple rule can save you many hours of
grief. When the tool “chatters,” it is not cutting in a
continuous fashion. Metal likes to be machined in a way
that allows the material to come off in a continuous strip
while the tool is in contact with the metal. If the tool is not
fed at a rate that is fast enough, the tool skips along the
surface, occasionally digging in. The surface of the tool
that is doing the most cutting will find a frequency of
vibration that is a product of all the variables involved. This
can cause anything from a high pitched whine on light, high
speed cuts to a resonating racket that can rip the work out
of the chuck on heavy cuts. If you maintain the same feed
rate and reduce the RPM, the feed will increase because
chip will be thicker. (If that sounds wrong at first, think of it
this way: At the same feed rate, if you cut the RPM in half,
twice as much metal must be removed with each rotation
FIGURE 23—Directions
of Feed and Cut when
working with a milling
machine
When using a mill, cut is
determined by the amount
of depth the cutter is set to
by the Z-axis handwheel.
Feed is supplied by either
or both the X- or Y-axis
handwheels depending on
the desired direction of the
cut. (See Figure 23.)
In normal lathe turning, the depth of cut is set by the crosslide
handwheel, and the feed is provided by the handwheel on
the end of the bed. When facing off the end of a work
piece held in a chuck or faceplate, the depth of cut is set by
the handwheel on the end of the bed, and the feed is provided
by the crosslide handwheel. (See Figure 24.)