Lathe Fundamentals

1
Lathe Fundamentals
2
Overview

• Safety
• Shop Etiquette
• Lathe 101
• Basic Terminology
• Calculating Feeds and Speeds
• Cutting Tools
• Before Machining
• Machining
• Maintenance
• Specific Lathe Controls

3
Safety

• Respect the machines
• Common Sense
• Wear safety glasses
• Avoid loose clothing
• Restrain long hair
• Never wear gloves
• Never wear shorts or sandals
• Stay alert

4
Shop Etiquette

• COE Student Shop
• Always leave machines cleaner
• Ask for help, if needed
• Come prepared
• Tooling list
• Plan of action
• Dimensioned drawings

5
Lathe 101 - Introduction

• The Basics
• The lathe is one of the most common machines
  found in todays modern machine shop. Used
  primarily to produce cylindrical workpieces.
• Different from a mill in that it produces a round
  diameter on a part by rotating a workpiece
  against a non-rotating single-point tool, as
  Figure 1. shows.
• The lathe, operated manually, changes the size,
  shape, and finish of a workpiece with a variety
  of cutting tools.

Fig. 1
6
Lathe 101 - Introduction

• Types Of Lathes
• The three types of lathes you may find in a
  machine shop today are
• Engine Lathe
• The original lathe is the engine lathe, shown in
  Fig. 1. This type of lathe positions and holds a
  workpiece on a desired centerline, while the
  spindle rotates the workpiece. As the workpiece
  spins, the cutting tool gradually passes along
  the surface of the workpiece, and a layer of
  material is removed.
• Engine lathes are the most frequently used manual
  lathes.

Fig. 1
7
Lathe 101 - Introduction

• Types Of Lathes
• Turret Lathe CNC Machining Centers
• The turret holds multiple cutting tools that
  rotate into position when needed. Each time the
  turret lever is activated, the turret spins or
  indexes and positions the next tool in the
  sequence. It is then ready to carry out different
  machining operations.
• Because the turret holds multiple tools, the
  machinist does not have to change tools each and
  every time a different tool is needed. There are
  automated versions of these lathes that are
  computer controlled and are called CNC Machining
  Centers.

CNC Machining Center
Turret
8
Lathe 101 - Introduction

• Types Of Lathes
• CNC Lathes
• Today, many shops use CNC lathes, like the one in
  Fig. 1.
• A CNC lathe is a type of lathe that uses computer
  numerical controls (CNC) to operate the lathe.
  These machines use single bit tooling.

Fig. 1
9
Basic Lathe Terminology
Compound Rest
Tool Post
Tailstock
Headstock
Chuck
Cross Slide
Ways
Bed
Feed Gear Box
Carriage
Lead screw
Apron
Brake Emergency (E) Stop
10
Basic Terminology

• Parts Of A Lathe
• The bed is the base and backbone of the lathe.
  The bed is a heavy, rigid frame made of cast iron
  on which all other components of the lathe are
  mounted and/or move.
• The ways are parallel, longitudinal rails located
  on the bed. There are two sets of inner and outer
  ways. The ways guide other components on the
  lathe, such as the tailstock.
• The headstock is mounted on the inner ways and
  provides the power to rotate the workpiece. It
  consists of a hollow spindle and a set of gears
  that rotate the spindle at a range of speeds that
  are operator adjustable

11
Basic Terminology

• Parts Of A Lathe
• The spindle is mounted in the headstock and
  carries the workholding devices, i.e. chuck or
  collet. The spindle has a hole extending through
  its length, through which a long bar stock can be
  fed. The size of this hole determines the maximum
  diameter of bar stock that can be machined when
  the materials must be fed through the spindle.
• The tailstock is located opposite of the
  headstock and supports the end of longer
  workpieces.The tailstock typically contains a
  center that holds the other end of the workpiece
  in place, but it can also hold a cutting tool, by
  way of a drill chuck.

12
Basic Terminology

• Parts Of A Lathe
• The carriage is the section of the lathe that
  slides along the ways and supports the
  cross-slide and cutting tool. The carriage
  contains the compound rest, which permits angular
  adjustment of the cutting tool. The compound rest
  can rotate with respect to the cross-slide, which
  permits further positioning of the tool being
  used.
• The leadscrew powers the carriage assembly. The
  leadscrew is a large, threaded rod that is
  located below and parallel to the ways.

13
Basic Terminology

• Coordinates
• With respect to the headstock

absolute
incremental
Z-Axis
X-Axis
14
Using the Digital Readout (DRO)

• Use the yellow arrow buttons to zero the DRO

15
Basic Terminology

• Indicating
• Dial indicator
• Can be attached to bed whendigital readout is
  not present
• (Z axis travel indicator)
• Used to indicate in a work piece
• when using a 4 jaw chuck a magnetic
  indicator stand can be used to hold the
  indicator.

16
Basic Terminology

• Tooling
• Collets (5C) Work Holding
• Collets run more true than a chuck
• Drill Chuck Tool Holding
• Mainly for drill bits
• Mounts on a Morse Taper
• arbor (1 thru 4 most common)
• Slides into tailstock

17
Basic Terminology

• Tooling
• Center Drill used first
• Keeps holes accurately positioned
• Twist Drill
• Reamer
• Usually pre-drill to 1/64th under
• Precise hole size
• Boring Bar Boring Holes
• Lathe Tool Bits Facing Turning Threading -
  Grooving

18
Basic Terminology

• Tool Post Holder
• Tool holders slide down onto tool post
• Twist handle to lock and release tool holders

19
Basic Terminology
Threaded Collar

• Work Holding Devices
• Chucks 3 And 4 Jaw Chuck
• The most common device used to hold and position
  parts on the lathe is the chuck. A chuck consists
  of three or four jaws that clamp down on the end
  of the workpiece.
• The most commonly used chuck has jaws that open
  and close together automatically centering the
  workpiece. Chucks are mounted to the lathe
  spindle using the two most common methods
  Spindle Nose with Long-Taper Key Drive (L-Series)
  the Cam-Lock Spindle (D-Series)

Long-Taper Key Drive - LeBlond
Long-Taper Wrench
Cam-Lock Spindle - Victor
Cam-Lock Wrench
20
Basic Terminology

• Work Holding Devices
• 3 Jaw Chuck
• The jaws open and close together automatically
  centering the workpiece. This kind of chuck
  usually has a 2 piece reversible set of jaws, or
  a complete other set, one set holds the larger
  work while the other set holds rings and small
  work.
• These 3 jaw universal chucks when in good shape
  center work accurately to within .002 to .003.

3 Jaw 2 Piece Reversible
Chuck (key) Wrench
3 Jaw Solid Jaw (2 Sets)
21
Basic Terminology

• Work Holding Devices
• 4 Jaw Chuck
• The 4 jaw independent chuck has four jaws and
  each must be moved separately with a chuck
  wrench it is used mainly to hold work that is
  not perfectly round.
• It may be used to hold work that is round,
  square, rectangular, or irregular in shape. This
  chuck is more accurate since the work can be
  centered with the use of a dial indicator.
• The jaws on this kind of chuck are solid
  reversible that is, they can be taken out and
  put on again in the opposite direction or a 2
  piece reversible jaw. They have steps so that
  different sizes of work can be held. There are
  also 4 jaw self centering chucks available.

4 Jaw Solid Reversible Jaws
4 Jaw 2 Piece Reversible Jaws
Chuck (key) Wrench
22
Basic Terminology
Victor

• Work Holding Devices 5 C Size
• Collet Chuck Split Spring Collet Type
• The collets are made to hold work which is close
  to a specific diameter. A spring collet should be
  used only for holding work which is within about
  .005 of the size of the collet. They are commonly
  used for work smaller then 1 inch in diameter.
• The most common type used is the draw-in type
  which fits in the nose of the lathe spindle with
  a hand wheel draw bar or in a collet closer
  system. The split collet with its taper is drawn
  up into a tapered sleeve of the same taper (or
  spindle). This causes a contraction of the
  gripping surfaces of the chuck and collet.
• Collets are available in sizes by 1/64 in. up to
  about 1 1/16 in. Collet chucks are very accurate,
  save time in mounting work and speed up the
  production of small work.

Round Collet
Hand Collet Closer System
Hex Collet
Quick Change Collet System
Square Collet
23
Basic Terminology
Parted
Necked

• Cutting
• Facing
• Turning
• Boring
• Taper Turning
• Center Drilling
• Parting - Grooving
• Hole Tapping
• Knurling
• Threading

Turned
Faced
Tapered
24
Basic Terminology

• Feeds and Speeds (F/S)
• Spindle Speed Speed (rpm) that the spindle
  and/or chuck rotates
• Feed Rate (feed) in/min How fast the carriage
  is moving (Z axis)

25
Calculating Feeds and Speeds

• Machinerys Handbook
• Can use formulas from here to calculate proper
  spindle speed
• Some lathes have charts on them.
• Computer Information Station
• Using the proper Feed Speed makes a big
  difference!

26
Cutting Tools
Fig. 1

• The most common cutting tools used are made from
  materials such as high-speed tool steels (HSS)
  and carbide.
• Most tools made from these steels are
  single-point tools, which means they contain a
  single cutting edge. Single-point tools, shown in
  Fig. 1 and in the next slide, are the most
  popular cutting tools used on the lathe hand
  ground HSS or the tools shown in Fig. 2 which are
  Brazed-tipped cutting tools.
• These tools are made from inexpensive material
  with a tip of more expensive cutting material
  brazed onto the cutting end. These materials
  include most commonly a C2 or C6 carbide. Carbide
  tooling can cut many materials at speeds up to
  four times faster than HSS. C2 used for
  non-ferrous metals and C6 used for tougher to
  machine ferrous metals.

Hand Ground HSS Tool Bits
Brazed Tip Carbide Tool Bits
Fig. 2
27
Cutting Tools Single Point
Cuts Left To Right
Cuts Right To Left
Cutting tip
Left-Hand Thread Cutting 60deg Right Hand
Height Adjustment Screw For Tool Holder Tool
A cutting tools tip should be set to the
centerline of the workpiece
28
Cutting Tools
Lathe Cut Off and Parting
Boring Bars
29
Carbide Insert Tooling

• Shops also use replaceable cutting inserts.
  Cutting inserts come in a variety of shapes, as
  you can see below. Inserts are secured in a
  toolholder and rotated so that there is a new
  cutting surface in the same location.

30
Before Machining

• Be familiar with the specific lathe you are
  using. Pre-View the terminology sections and the
  lathes video.
• Make sure work and tooling are tightly secured.
• Be sure you are using the proper cutting tool for
  your operation and material.
• If you need help, ASK!
• Check Our Web Site! www.coestudentshop.engr.wisc.e
  du

31
Before Machining

• Always lock axes for straight cuts
• Clear the cutting area of chips with a chip brush
  (Never Use Your Hands)
• Always know the location of the brake and
  Emergency (E)
• stop if available

32
Machining

• Changing The Chuck
• Use a chuck key (Victor) or spanner wrench
  (LeBlond 1 2) located in the lathe drawers
  Make sure the threaded collar on the LeBlonds are
  very tight by hand, then tap on the spanner
  wrench once with a rubber mallet.
• Always use a support board under the lathe
  spindle nose incase the chuck drops (protects the
  lathe bed)
• Check The Appropriate Lathe Video Also!

33
Machining - Using a Collet

• Remove the adjustable chuck
• Place collet holder in machine
• Align collet with key in holder
• Use handle to tighten collet work into place

Collet Holder
Handle
Collet
34
Machining

• Operations
• Changing the chuck collet use
• Facing
• Turning
• Center Drilling
• Boring
• Taper Turning
• Parting Grooving
• Drilling
• Hole Tapping
• Knurling
• Threading using a die and holder
• Reaming

35
Machining

• Outer Diameter Cutting Operations
• Outer-diameter operations are cutting
  operations that occur on the outer surface of the
  workpiece
• Facing - is the machining of a flat surface on
  the end, or face, of a workpiece. Facing is
  sometimes used to remove uneven, rough surfaces
  and burrs from a workpiece.
• Turning is the machining of the external surface
  of round parts. During turning, a part is held at
  one or both ends while it rotates against a
  single-point tool. The cutting edge is forced
  against the surface of the workpiece, cutting
  metal as the tool is fed along the surface.

36
Machining

• Outer Diameter Cutting Operations
• Parting - also called cutting off, involves
  separating a complete piece from stock. Parting
  is important because you can ruin the whole job
  if the part is not cleanly removed.
• OD grooving is a simple machining process during
  which a cutting tool is plunged into a workpiece
  to create a groove or channel. There are
  essentially three types of grooves square-cut
  grooves, round-cut grooves, and V-cut grooves.
• OD threading - is a special turning operation
  that uses a single-point tool to cut spiraling
  ridges (threads) down the length of a workpiece.
  These threads are found on screws, bolts, and
  other types of fasteners. The lathe has the
  ability to cut many different types of threads
  with the most common being a 60 degree thread.

37
Machining

• Inner Diameter Cutting Operations
• Lathes are also capable of performing cutting
  operations on the inner surface of a workpiece.
  Inner-diameter operations (ID) hold the workpiece
  on one end, while the cutting tool enters the
  workpiece at the other end.
• Drilling simply creates a hole in the workpiece.
  A drilled hole is the least accurate type of hole
  made.
• Boring enlarges the inner diameter of a
  preexisting hole. This process improves the
  accuracy of the hole and makes it more round. On
  the lathe, boring is essentially like internal
  turning.

38
Machining

• Inner Diameter Cutting Operations
• Reaming smoothes the internal surface of a hole.
  It uses a special multi-point tool to remove
  metal from inside a hole. Reaming only removes
  small amounts of metal. An accurate method of
  finishing a specific hole diameter.
• Tapping cuts internal threads into a drilled
  hole. This process is similar to tapping a hole
  off the lathe.
• ID grooving cuts a single circular channel or
  groove into a drilled hole.

39
Facing

• Gives the work a smooth and true
  (perpendicular) face and brings it to the
  desired length
• Use a left-hand tool and cut from the outside to
  the center as pictured
• Position tool with center of work
• Use cutting fluid as needed

40
Turning

• Gives smooth cylindrical shape or reduces the
  diameter
• Use right-hand tool and feed left Transfers
  cutting forces to the sturdy
• headstock
• Use tailstock with live center for support if
  needed (do not use a dead center does not
  rotate and needs to be constantly lubricated.
• Look up material cutting speed (SFM, surface feet
  per minute)
• Calculate spindle speed (RPM)
• Start with a lower feed speed (IPM, inches per
  minute).
• Check surface finish adjust
• feed speed as needed

41
Center Drilling

• Aligns (Centers) drill bit (spotting) if done
  before drilling
• Makes countersink hole allowing live center
  support from tailstock side
• Use cutting fluid
• as needed

42
Boring

• Enlarge or true an existing hole
• Similar to external turning
• Align tip with center of piece
• Use cutting
• fluid as needed

43
Taper Turning

• Used to make angle cuts on to work piece
• Move compound slide to correct angle
• Use left hand tool (depends on compound cutting
  direction being used)
• Align cutting tip to center of work piece
• Hand feed from outside to center (depends on tool
  cutting direction)
• Angle read from compound slide is angle from
  centerline of piece

44
Parting, Recessing, Grooving

• Purpose - Cut to length or remove center holes
• Align tip of tool with center of piece
• Use slower spindle speeds
• Use cutting fluid as needed
• Hand feed slowly but fast enough to maintain a
  chip
• Parting tool can also be used for recessing and
  grooving

45
Drilling

• Makes center holes
• Use drill chuck in tailstock
• Use tailstock feed to control depth
• Always center drill work first
• Make sure the tailstock is locked into position
• Use cutting fluid as needed
• Make sure the tailstock spindle is out 1 inch
  before inserting drill chuck

46
Using the Live Center

• Supports piece between headstock and tailstock

When to use a live center General rule of thumb
for steel, aluminum, copper and brass Use a
live center anytime a piece is sticking out of
the chuck/collet more than 3 times its diameter
Example A 1 diameter piece of cold rolled
steel would be 3.00 inches. Note Reduce this
length with softer materials such as plastics.
47
Tapping

• Use a live center or a drill chuck, dead center
  and tap handle in the tailstock spindle
• Lock the tail stock when dead center is snug with
  tap handle and work piece
• Turn tap handle andapply light pressure
• with tailstock feed
• handle simultaneously
• NOTE Do Not Turn On Lathe

48
Threading

• Use thread cutting tool bit to cut threads into
  work piece
• Not a common procedure for thestudent shop

49
Maintenance

• Clean up Main points
• Sweep up large chips and vacuum up
• the small chips.
• Empty the lathe chip pan (if it has one).
• Limit use of air hose.
• Wipe off machine along with the bed/ways with a
  shop rag.
• Make sure the tailstock and carriage are all the
  way to the back (right) of the lathe when
  finished.

50
Maintenance

• Clean up
• Return all lathe tooling to the appropriate
• drawer.
• Return items that have been checked out
• back to the toolcrib.
• Make sure there are no
• chips on the floor or lathe

Vacuum (aka R2D2)
51
Maintenance

• Oil machines
• Ways Use blue or silver oil cans to apply oil to
  the ways/bed rails after each use.
• Other oiling processes done by shop personnel.

Oil Cans are labeled Way Oil Note Follow the
online video for more details on cleaning the
lathes!
52
Final Notes

• Now, make some parts and learn to use the lathes
  in the COE shop
• Ask someone who knows, or check with the staff.
• Take some time and view the videos located on our
  web site (www.coestudentshop.engr.wisc.edu)
  before starting, and then again on each lathes
  own computer.

53
Conclusion
College Of Engineering Shops University Of
Wisconsin Madison Never be afraid to ask for
help Experience is the best way to learn!
Continue For Specific Machine Lathe Controls
54
Specific Lathe Controls

• LeBlond 1
• Hardinge 1
• Victor
• LeBlond 2

55
Lathe Controls LeBlond No. 1
Feed Control Levers
Spindle Control Handle
Power On / Off Fast or Slow Spindle Speed
Range
56
Lathe Controls LeBlond No. 1
Feed Reverse Lever
Spindle Speed Control Levers
Feed Control Lever
57
Lathe Controls LeBlond No. 1
Thread Cutting Engagement Lever
X Z Axis Auto Engagement Lever
58
Lathe Controls Hardinge No. 1
Forward / Reverse
Power On/Off
59
Lathe Controls Hardinge No. 1
Push Button Spindle Speed Control
Collet Closer
60
Lathe Controls Hardinge No.1
Gearbox Disconnect
Spindle
Use Only When Threading
Threading Direction Control Lever
Spindle Control Lever High/Low
Thread Selection Controls
61
Lathe Controls Hardinge No. 1
Cross Slide Power Feed Control Handle X - Axis
Carriage Lock Handle
Carriage Power Feed Control Handle Z - Axis
Lead Screw Nut Handle Threading Use Only
62
Lathe Controls Hardinge No. 1
Carriage Feed Direction
Carriage Feed On / Off
Carriage Speed Range
Carriage Speed Control Knob
63
Lathe Controls Victor
Compound Rest
Tool Post
Tailstock
Headstock
Chuck
Cross Slide
Bed/Ways
Carriage
Feed Gear Box
Apron
Brake E Stop
64
Lathe Controls Victor
Feed Selector Lever
Feed Threading Selector
Spindle Control Lever
Feed Selector Dial
Spindle Toggle Button
Main Power On / Off
65
Lathe Controls Victor
Spindle Speed Selector
Speed Range Selector Lever
Carriage Feed Direction Lever
66
Lathe Controls Victor
Carriage Lock
Thread Cutting Engagement Lever
X Z Axis Feed Selector
Auto Feed Engaging Lever
67
Lathe Controls LeBlond No. 2
Speed Calculator
Speed Control Lever
Feed Reverse Lever
Thread Select Lever
Spindle Speed Levers
Power On/Off
68
Lathe Controls LeBlond No. 2
Compound Handle
Carriage Hand Wheel
Cross Feed Handle
Carriage Cross Feed Select Lever