Introduction
If you are new to metalworking lathes and lathe work, this
page will help you understand some of the basic concepts, terminology and
capabilities. In essence, a lathe, whether for woodworking or metalworking,
rotates a cylindrical work piece along its axis and removes material from the work
piece to form it into a specific shape.
On a woodworking lathe, the cutting tools are usually
hand-held against a support and are moved in and out and back and forth along
the surface of the work by hand to form a shape such as a table leg.
On metalworking lathes, the cutting tools are held rigidly
in a tool holder that is mounted on a movable platform called the carriage. The
tool is moved in and out by means of hand cranks and back and forth either by
hand cranking or under power from the lathe. The result is that material can be
removed from the work piece under very precise control to produce shapes that
are truly precision made. Dimensional accuracies of one-one-thousandth of an
inch (.001") are typical. However, because of the inherent rotational
nature of a lathe, the vast majority of the work produced on it is basically
cylindrical in form. In spite of this, the lathe is an extremely versatile
machine capable of producing a surprising variety of objects.
History
The lathe is
an ancient tool, dating at least to the Egyptians and known and used in
Assyria, Greece, the Roman and Byzantine Empires.
The origin of
turning dates to around 1300 BC when the Egyptians
first developed a two-person lathe. One person would turn the wood work piece
with a rope while the other used a sharp tool to cut shapes in the wood. The Romans
improved the Egyptian design with the addition of a turning bow. Early bow
lathes were also developed and used in Germany, France and Britain. In the Middle Ages
a pedal replaced hand-operated turning, freeing both the craftsman's hands to
hold the woodturning tools. The pedal was usually connected to a pole, often a
straight-grained sapling. The system today is called the "spring
pole" lathe (see Pole lathe). Spring pole lathes were in common use into the
early 20th century. A two-person lathe, called a "great lathe",
allowed a piece to turn continuously (like today's power lathes). A master
would cut the wood while an apprentice turned the crank.[1]
During the Industrial Revolution, mechanized power
generated by water wheels or steam engines was transmitted to the lathe via line shafting,
allowing faster and easier work. The design of lathes diverged between
woodworking and metalworking to a greater extent than in previous centuries. Metalworking
lathes evolved into heavier machines with thicker, more rigid parts. The
application of lead screws, slide rests, and gearing produced
commercially practical screw-cutting lathes. Between the late 19th and
mid-20th centuries, individual electric motors at each lathe replaced line
shafting as the power source. Beginning in the 1950s, servomechanisms
were applied to the control of lathes and other machine tools via numerical
control (NC), which often was coupled with computers to yield computerized
numerical control (CNC). Today manually controlled and CNC lathes coexist in
the manufacturing industries.
What is
Lathe?
A lathe is a machine
tool which spins a block of material to perform various operations such as cutting, sanding, knurling, drilling, or deformation with tools that are applied
to the work piece to create an object which has symmetry about an axis
of rotation.
Lathes are
used in woodturning,
metalworking,
metal
spinning, and glass working. Lathes can be used to shape pottery, the
best-known design being the potter's
wheel. Most suitably equipped metalworking lathes can also be used to
produce most solids of revolution, plane surfaces and screw
threads or helices. Ornamental lathes can produce three-dimensional solids of
incredible complexity. The material can be held in place by either one or two centers,
at least one of which can be moved horizontally to accommodate varying material
lengths. Other work holding methods include clamping the work about the axis of
rotation using a chuck or cullet, or to a faceplate, using clamps or dogs.
Examples of
objects that can be produced on a lathe include candlestick
holders, cue
sticks, table legs, bowls,
baseball
bats, musical instruments (especially woodwind instruments),
crankshafts
and camshafts.
Glossary of Lathe Terms
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Front part of
the carriage assembly on which the carriage hand wheel is mounted
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Main
supporting casting running the length of the lathe
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Assembly that
moves the tool post and cutting tool along the ways
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A wheel with a
handle used to move the carriage by hand by means of a rack and pinion drive
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A clamping
device for holding work in the lathe or for holding
drills in the tailstock. Drill chucks are sometimes referred
to as Jacobs Chucks, a brand name that popularized that style of chuck.
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Movable
platform on which the tool post is mounted; can be set at an angle to the work
piece. Also known as the compound slide and compound rest.
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A wheel with a
handle used to move the compound slide in and out. Also known as the compound
feed.
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A hand wheel
or crank that moves the cross-slide by turning a screw. Also the action of
moving the cross slid using the cross feed hand wheel.
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Platform that
moves perpendicular to the lathe axis under control of the cross-slide hand
wheel
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Lever to
engage the carriage with the lead screw to move the carriage under power
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The main
casting mounted on the left end of the bed, in which the spindle is mounted.
Houses the spindle speed change gears.
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Precision
screw that runs the length of the bed. Used to drive the carriage under power
for turning and thread cutting operations. Smaller lead screws are used
within the cross-slide and compound to move those parts by precise amounts.
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Main rotating
shaft on which the chuck or other work holding device is mounted. It is
mounted in precision bearings and passes through the headstock.
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Cast iron
assembly that can slide along the ways and be locked in place. Used to hold
long work in place or to mount a drill chuck for drilling into the end of the
work.
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A wheel with a
handle used to move the tailstock ram in and out of the tailstock casting.
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A holding
device mounted on the compound into which the cutting tool is clamped
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Precision
ground surfaces along the top of the bed on which the saddle rides. The ways
are precisely aligned with the centerline of the lathe.
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Types of Lathe Machines
Wood
Lathes
The simplest lathe type is the wood lathe. As the
name suggests, it is designed for turning wood. Wood lathes are small machines
consisting of a bed, headstock, tailstock and tool rest. There are no precision
ways as are found on a metal-working machine, since the cutting tools are moved
by hand and not by machine power. Great skill is needed to control the cutting
tool to accurately turn smooth curves and complex contours on the work piece.
The spindle is usually driven by a belt connected to a motor, and speed changes are made by manually moving the belt to one of several pulleys mounted to the back of the spindle.
Lathe tools are held manually against the work, with the support of the tool rest. The tool rest is adjustable and is clamped to the bed at a position convenient for the operation at hand.
The spindle is usually driven by a belt connected to a motor, and speed changes are made by manually moving the belt to one of several pulleys mounted to the back of the spindle.
Lathe tools are held manually against the work, with the support of the tool rest. The tool rest is adjustable and is clamped to the bed at a position convenient for the operation at hand.
Engine
Lathes
Engine
lathes are the classic metal turning workhorses of the production machine shop.
They come in many sizes and are adaptable to working virtually any material.
These machines have a longitudinal bed to which is mounted a headstock and
tailstock.
As in the wood lathe, the headstock contains the spindle. However, the spindle drive is more complex, including variable speed capability or selectable gearing to provide a much wider range of speeds.
A carriage moves back forth on bed ways for longitudinal turning. A cross-slide and compound rest are mounted to the top of the carriage to provide cross and angular cutting capability.
The lathe cutting tools are moved against the work manually using hand wheels or automatically under the power of a lead screw that is driven by gears in the headstock.
As in the wood lathe, the headstock contains the spindle. However, the spindle drive is more complex, including variable speed capability or selectable gearing to provide a much wider range of speeds.
A carriage moves back forth on bed ways for longitudinal turning. A cross-slide and compound rest are mounted to the top of the carriage to provide cross and angular cutting capability.
The lathe cutting tools are moved against the work manually using hand wheels or automatically under the power of a lead screw that is driven by gears in the headstock.
Tool room Lathe
The tool room lathe is a small- to
medium-sized engine lathe specially designed for high-precision work. These
machines find use in tool and die shops, where custom parts and precision
fixtures are produced, often in support of production machining operations.
Tool room lathes are manufactured with special attention to spindle accuracy, smooth operation and precise alignment of the carriage and cross slide. A tool room lathe is capable of better accuracy and precision than a standard engine lathe.
Tool room lathes are manufactured with special attention to spindle accuracy, smooth operation and precise alignment of the carriage and cross slide. A tool room lathe is capable of better accuracy and precision than a standard engine lathe.
Turret
Lathe
Turret lathes are used in
production machine shops where several sequential operations are needed on
single work piece. It is costly and time consuming to remove a work piece from
one machine and hold it in another. Removing and beholding a work piece also
introduces errors in work alignment and machining accuracy.
The turret lathe has a rotating
turret mounted to the carriage so that as soon as an operation with one tool is
completed, the turret is indexed to bring another tool into working position.
The part is then machined again without having to remove it from the chuck or collect.
Eight (or more) different operations can be performed on a work piece using
this type of machine.
CNC
Lathe
Computer numerically controlled
lathes have largely supplanted engine lathes in production machining
environments. CNC lathes offer the advantages of greater powered axis drives,
feedback control to monitor and maintain tool positioning and high-speed repeatability
of complex machine motions. Once a program is verified, an operation can be
quickly set up again without the need for tedious manual adjustments.
CNC lathes excel at cutting curved
contours without the need for specially shaped tools. This is done by
programmed variation of the speed of two motion axes and the spindle
simultaneously---an operation that is impossible with an engine lathe.
Lathe Specifications
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FEATURE
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4000(4100)
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4400(4410)
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Swing over bed
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3.50" (90 mm)
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3.50" (90 mm)
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Swing over carriage
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1.75" (45 mm)
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1.75" (45 mm)
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Distance between centers
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8.00" (200
mm)
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17.00" (430
mm)
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Hole through spindle
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.405" (10 mm)
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.405" (10 mm)
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Spindle nose thread
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3/4"-16 T.P.I.
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3/4"-16 T.P.I
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Spindle nose taper
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#1 Morse
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#1 Morse
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Travel of crosstie
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4.25" (110
mm)
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4.25" (110
mm)
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Taper of tailstock spindle
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#0 Morse
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#0 Morse.
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Protractor graduations
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0° to 45° by 5°
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0° to 45° by 5°
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Hand wheel graduations
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.001" (.01
mm)
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.001" (.01
mm)
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Length overall
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24" (610 mm)
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32.25" (820
mm)
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Width overall
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7.5" (190 mm)
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8.75" (220
mm)
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Height overall
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6" (150 mm)
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8" (200 mm)
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Shipping weight
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24 lb. (10.9 kg)
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30 lb. (13.6 kg)
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Motor/Speed
Control
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90
Volts DC with electronic speed control that accepts any incoming current from
100VAC to 240 VAC, 50 Hz or 60 Hz. Click here for more detailed motor and
other machine specifications.
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Spindle speed range
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70-2800 RPM
continuously variable by electronic speed control
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Lathe Safety
1. YOU are responsible for your own
safety and proper machine operation.
2. As
small as it is, the mini lathe, like any power tool, can be dangerous if used
improperly. If you are new to metal working, get in the habit right from the
start of rigorously following good safety practices. Here are some tips:
3. Always
wear eye protection - preferably industrial quality safety glasses with
side-shields. The lathe can throw off sharp, hot metal chips at considerable
speed as well as spin off spirals of metal that can be quite hazardous. Don't
take chances with your eyes.
4. Wear
short sleeve shirts, if possible, or shirts with snugly fitting cuffs if long
sleeve. Loose sleeves can catch on rotating work and quickly pull your hand or
arm into harm's way.
5. Wear
shoes - preferably leather work shoes - to protect your feet from sharp metal
chips on the shop floor and from tools and chunks of metal that may get
dropped.
6. Remove
wrist watches, necklaces, chains and other jewelry. It's a good idea even to
remove your wedding ring since it can catch on rotating work and severely
damage your ring finger and hand.
7. Tie
back long hair so it can't get caught in the rotating work. Think about what
happens to your face if your hair gets entangled.
8. Always
double check to make sure your work is securely clamped in the chuck or between
centers before starting the lathe. Start the lathe at low speed and increase
the speed gradually.
9. Get
in the habit of removing the chuck key immediately after use. Some users recommend
never removing your hand from the chuck key when it is in the chuck. The chuck
key can be a lethal projectile if the lathe is started with the chuck key in
the chuck.
10. Keep
your fingers clear of the rotating work and cutting tools. This sounds obvious,
but I am often tempted to break away metal spirals as they form at the cutting
tool.
11. Avoid
reaching over the spinning chuck. For filing operations, hold the tang end of
the file in your left hand so that your hand and arm are not above the spinning
chuck.
Never use a file
with a bare tang - the tang could be forced back into your wrist or palm.
Application
Ø A CNC lathe is a machine tool
designed to remove material from a rotating work piece, using a cutting tool.
Some lathes can form hollow parts by a process called metal spinning. These
parts have circular cross-sections. Metal and other materials can be turned on
a lathe, including wood and plastics. CNC controlled lathes use a computer to
control the process of making each part with repeated
Ø A
metal lathe usually spins the work piece along a horizontal axis. A mandrel or
chuck is mounted to the Headstock of the lathe. A follower block or tail block
is mounted to the tailstock. A blank piece is clamped to the
Ø Lathe
and pressure is applied to the blank via a cutting tool. Material is cut away
on each pass across the blank.
Ø After
each pass, the lever arm is moved closer to the final position. Eventually,
when the proper amount of material has been removed, the part is completed.
Ø Yukawa
AC drives can be interlocked with the CNC control systems so the operation of
the CNC controller and the AC drive are synchronized.
Ø In
addition, the Energy Saving Mode in Yukawa AC drives automatically detect
changes to the amount of torque required during shaping and finishing phases.
This feedback enables the drive to quickly detect changes as the cutting tool
becomes dull.