Sherline 5000 Mill Assembly Instructions

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BORING TOOLS
The use of this tool requires the existence of a drilled or
cored hole, or it may be used to enlarge the bore of a tube.
The work must be mounted in a chuck or on a faceplate
and the boring tool set as shown in Figure 34. Note the
clearance behind the cutting point as shown in Figure 38
below.
FIGURE 38—Boring
tool clearance
A slow rate of feed should
be used, as the turnings
are not able to escape
freely from the hole and
can jam the tool. Frequent
withdrawal of the tool to
allow turnings to escape may be necessary. Care should
be taken not to feed the tool beyond the depth required or
to feed so deeply as to damage the chuck or faceplate.
Where a hole must be bored right through the work, it should
be shimmed out from the faceplate to provide clearance
for the tool to feed through. The leadscrew handwheel
graduations can be used to indicate the correct depth at
which to stop the feed. Notice that, with boring, the depth
of cut is increased by moving the tool and crosslide towards
the operator and not away as with normal turning.
The boring of holes often necessitates greater than normal
overhang of the tool from the tool post, so the depth of cut
and rate of feed should be reduced from normal.
INSERTED TIP CARBIDE CUTTING TOOLS
Sherline brings the home shop machinist into the space age
with cutting tools that add a new dimension to small lathes.
When working with tough metals, high-speed steel tools
need constant sharpening and have a relatively short life.
Brazed carbide tools cut great but chip easily. Inserted
carbide cutting tools are the answer and have replaced
those other tools in the modern machine shop. Carbide
inserts have the ability to consistently give good finishes
and long tool life at a much higher cutting speed. This is
especially important with small lathes, because they do not
have excessive power at low RPM. With inserted carbide
tools you can cut stainless steel at the same RPM you
were formerly using to cut aluminum with high-speed steel
tools without any sacrifice in quality in surface finish.
These tools are more expensive than high-speed steel;
however, they are worth every penny if you have problems
grinding your own steel tools or are cutting exotic materials
like stainless steel. Sherline offers a tool post (P/N 7600)
that holds the larger 3/8" square tool shanks used to hold
carbide or diamond inserted tips. It also has a 3/8" round
hole for boring tools.
A good starting point for an inserted tip tool is the P/N 2256
right-hand holder with a 35° offset. This holder uses the
P/N 7605 carbide insert, which is a 55° insert good for
turning, facing and profiling. A left-hand tool is also available
as P/N 2257, or a set of both left- and right-hand tools is
CLEARANCE
P/N 2258. Tools are also available to hold 80° inserts, which
are slightly less versatile but offer longer tool life because
of their stronger, more square shape. These tools should
not be used to cut hardened steels or piano wire. Materials
such as those should be ground to shape, not cut. Abrasive
materials such as glass-reinforced plastics can be easily
cut with these tools.
Another tool available to
Sherline machinists that holds
carbide inserts is the 3/8" IC
55° negative rake insert tool
holder (P/N 7610). The
indexable carbide insert sits on
the tool holder at a 5° negative
angle. This gives the sides of
the cutter clearance even
though the insert has square
sides. By having square sides,
both top and bottom of the insert can be used as cutting
edges, giving a total of four cutting edges on each insert.
Because of its design, it cuts like a positive rake cutter,
which requires less rigidity than a negative rake cutter. It
gives you the best of both worlds—the four cutting edges
of a negative rake tool along with the lower stress loading
of a positive rake cutter, which is appropriate for a lathe of
this type.
When searching for a mirrorlike finish on copper or
aluminum, a four-sided diamond insert (P/N 7609) and a
tool holder (P/N 7619) are also available. Though expensive,
the four cutting edges of the diamond insert mean you are
really getting four tools in one, making it a better deal than
it may first appear.
NOTE: Never attempt to cut steel with a diamond
cutter.
While inserted tip carbide and diamond cutting tools will
improve the performance of the Sherline lathe, they will
not correct poor machining technique. Rigid setups are a
must for tools such as these.
TURNING SPEEDS
The following chart in Figure 41 provides a guide to speeds
at which work of differing materials should be rotated. Note
that the turning speed is inversely proportional to the
diameter of the work; that is, the larger the diameter, the
slower the turning speed. Material often differs in hardness,
so these figures may have to be adjusted. The harder the
material, the slower the turning speed should be.
FIGURE 40—Negative
rake insert tool holder
(P/N 7610)
FIGURE 39—Carbide insert tool and tool post. The
tool post holds both 3/8" square and round tools.
P/N 2256 TOOL HOLDER
CARBIDE INSERT
P/N 7600 TOOL POST
FOR 3/8” INSERT
HOLDERS AND 3/8”
ROUND BORING
TOOLS
A SPECIAL TORX DRIVER
FOR TIGHTENING THE
INSERT HOLD-DOWN
SCREW IS INCLUDED
WHEN CARBIDE TIPS
ARE PURCHASED