Sherline 5000 Mill Assembly Instructions

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LATHE OPERATING INSTRUCTIONS
CAUTION!
READ ALL OPERATING INSTRUCTIONS CAREFULLY BEFORE
ATTEMPTING ANY MACHINING OPERATIONS.
LEVELING THE CUTTING TOOL
Each type of turning work requires the correct tool for the
job. It is important that the cutting tool be sharp and
correctly set up in the tool post. The cutting edge of the
tool should be exactly level with the center height of the
lathe. Check this by bringing the tool tip up to the point of
either the headstock center or tailstock center. (See Figure
24A.) We also manufacture a simple tool height adjustment
gage that allows you to check tool height at any time by
measuring from the table surface. (See Figure 24B.)
FIGURE 24—Leveling the tool using (A) the tip of a
head- or tailstock center or (B) Sherline’s tool height
gage P/N 3009.
NOTE: Upper position is for tools
held in extended tool post used
with riser blocks.
HEIGHT GAGE
P/N 3009
CROSSLIDE
TOOL POST
CENTER
A
B
The standard Sherline tool post is designed to hold common
1/4" square tool bits which have had a few thousandths of
an inch (.1 mm) ground off the top edge for sharpening.
Loosen the hold-down bolt and slide the tool post as close
to the center as possible. The tip of the tool bit may be
raised or lowered by sliding a shim* underneath it. The
cutting edge must be on center or just below center (0.004"
or .01 mm maximum). Ensure that the tool is fixed securely
in position by firmly tightening the socket head screws. Try
not to have the tool cutting edge protruding more than 3/8"
(10 mm) from the tool post.
*NOTE: Thin metal shim stock is available for this purpose.
If you don’t have any metal thin enough, a single thickness
of paper business card stock will usually do the job. Do not
use more than one thickness as it will compress too much.
Our optional rocker tool post (P/N 3057) allows this
adjustment to be made without shims. It comes standard
with the Model 4400/4410 long bed lathe.
INITIAL TEST CUTTING
If you have never operated a lathe before, we suggest that
you make a trial cut on a scrap of material to learn the
operation of the machine. In a 3- or 4-jaw chuck, secure a
piece of round aluminum stock approximately 3/4" (19 mm)
diameter and 1-1/2" (38 mm) long. Secure the presharpened
1/4" square cutting tool supplied with the lathe in the tool
post, making sure that it is properly positioned. First, turn
the speed control all the way counterclockwise, then turn
the motor on. Bring the speed up to approximately 1000
RPM (about 1/3 speed). To establish tool position in
relation to the work, bring the tool in slowly until it just
starts to scribe a line on the work. Crank the tool towards
the tailstock until it clears the end of the work. Advance
the tool .010" (.25 mm) using the crosslide handwheel (10
divisions on the inch handwheel scale). Using the bed
handwheel, move the tool slowly across the work toward
the headstock.
Cutting tools used on lathes are designed to remove metal
much as paper is removed from a roll. It takes a positive
feed rate to accomplish this. If the feed rate isn’t fast
enough, it would be similar to tearing an individual sheet
of paper off the roll. The results when cutting metal would
be shorter tool life, a poor finish and tool “chatter.” Chatter
is a function of rigidity, but it is controlled by speed (RPM)
and feed rate.
Since you already have a piece of aluminum chucked up,
experiment with speed and feed rate. You just took a cut of
.010" (.25 mm) and probably noticed that the machine didn’t
even slow down in the slightest. Now take a 1/2 inch long
cut .050" or 1 mm deep, which is one complete revolution
of the handwheel. If you used the sharpened cutting tool
to get to the end of the cut in the same amount of time. The
chip is twice as thick, so the feed is GREATER at lower
RPM if the feed RATE stays constant.)
When a tool chatters, it gets dull faster, because it must
keep cutting through the previously machined surface that
has been “work hardened” by machining. As you can
imagine, there are limits to how much you can increase
feed rate, so the answer lies in adjusting both speed and
feed to achieve the proper cut.
Proper cutting speed is the rate a particular material can
be machined without damaging the cutting edge of the tool
that is machining it. It is based on the surface speed of the
material in relation to the cutter. This speed is a function of
both the RPM of the spindle as well as the diameter of the
part or size of the cutter, because, as the part diameter or
cutter size increases, the surface moves a greater distance
in a single rotation. If you exceed this ideal speed, you can
damage the cutting tool. In the lathe and mill instructions,
we give some examples of suggested cutting speeds, but
what I wanted to get across here is that the damage isn’t a
slow process. A tool can be destroyed in just a few seconds.
It isn’t a case of getting only one hour of use instead of
two. The cutting edge actually melts. If you machine tough
materials like stainless steel, you will ruin more tools than
you care to buy if you don’t pay a lot of attention to cutting
speeds. Charts showing suggested cutting speeds for
various materials are included in both the lathe and mill
sections that follow.