Presentation on theme: "The Metalworking Lathe"— Presentation transcript:
1 The Metalworking Lathe Unit 58Metalwork Technology and Practice
2 Lathe Operation Principle Lathes operate on the principle of a cutting tool removing metal as it is being fed into a revolving work piece. (Fig 58-2 pg. 451)
3 Kinds of LathesManually Operated Lathe: Used to make single parts and small quantities of multiple parts or for repair of worn parts.Screw Machines and Turret Lathes: Used for production runs of a few hundred parts.Numerically Controlled and CNC: Used for short but rapid production runs. These are replacing the Manual Lathes.Automatic Lathes: Used for production runs of thousands identical partsVertical Turret Lathes: Used to machine parts of a large diameter.
4 Sizing Lathes Lathes come in various sizes Lathes are sized by the swing and bed length.Swing: Is the largest diameter work piece that can be turned on the machine.The swing is measured by the distance from the center point of the chuck to the bottom of the bed. Multiply this measurement times two to reach the largest diameter stock that can be turned.The bed is measured from front to the back of the machine.(See Fig pg 453)
6 Lathe Main Parts Bed: The main frame upon which the machine is built. Headstock: Always on the left hand side of the bed. This contains the drive mechanisms of the lathe (motor). This part will accept different chucks.Tailstock: Always clamped to the right side on the lathe bed. This part moves on the bed. This part will accept live centers, dead centers, drill chucks, tapered shank drills, and reamers.Both headstock and tailstock contain spindles.
8 Headstock Drive System Belt Driven: This is the most common upon older lathes. A V-belt will drive all the moving parts off the electric motor.Gear Driven: A series of gears operate the moving partsV-belt and Manual-shift systems require the operator to change speeds by changing the belts to different pulleys.Lever-shift systems and variable speed drive systems allow the operator to change speeds by the movement of a lever.
10 Carriage FeedLongitudinal Feed: When the tool is fed along the work, parallel with the bed.TurningBoringCross Feed: When the tool is fed across the end of the work piece.Facing(See Fig pg. 456)
11 Carriage Control (See Fig. 58-20 pg. 457) Apron Handwheel: Used for manual longitudinal movement.Cross-feed Knob: Used to move the cross slide in and out manually.Compound Rest: Holds the toolholder and cutting tool that is mounted on the cross- slide which is fed manually with the compound-rest knob.
14 Safety Precautions Always wear safety glasses Do not wear loose clothing or long sleevesShort sleeves are recommendedNever wear a ring or watchRings and watches can get caught in revolving work or lathe partsIf metal objects would fall on the hand this would cause the ring to bend or break. Removing a bent ring is painful!!!
15 Safety Precautions Know your lathe parts Not knowing what certain levers do and how they operate could can be dangerousKnow where your emergency shut down switches are located atDo not operate a lathe without the designed safety featuresStop the lathe then shut off the power when checking measurements and removing stock from chuck or spindle
16 Safety Precautions Do not attempt to measure revolving parts If the machine is equipped, use the emergency foot stop to stop the lathe. Never try to stop the lathe by hand!!!Never use a rag or paper towel to clean the parts while they are revolving in the latheMake sure that all parts are secured tightly in the lathe before starting. Parts could fly out if they are not.
17 Safety PrecautionsThe chuck key is always part of your hand while installing parts into the chuck. Never remove your hand from the chuck key until all parts are secured properly and the chuck key has been placed in its designated location.If the lathe is started with the chuck key in place the following could happenThe chuck key could fly out and injure someone or hit the lightsThe chuck key could become jammed against the lathe bed, damaging the wrench, lathe bed, chuck, and lathe spindle
18 Safety PrecautionsKeep the floor free from grease, oil, metal cutting tools, and work piecesNo horseplayRemove the metal chips / shavings from the lathe with a chip brush. Never use a cloth or your hands.Move the carriage out of the way or down the bed while polishing, filing, cleaning, and when making adjustments to the work.
19 Methods of Holding Workpieces in a Lathe Unit 59Metalwork Technology and Practice
20 Spindle NosesHeadstock Spindle: Where all work piece holding devices are attached to and driven by.Three types of spindle noses:Threaded Spindle Nose: Accommodates chucks and face plates.Cam-Lock Spindle Nose: Notched rods attached to the back of the chuck are aligned with holes on the spindle face.Long Taper Key-Drive Spindles: The chuck is placed so that the key on the spindle nose lines up with the keyway in the chuck.See Fig. 59-1, 59-2, and 59-3)
21 Lathe Chucks Five Kinds of Lathe Chucks: Four JawThree JawColletSpindleStep(See Fig 59-4, 59-5, 59-6, 59-7, 59-8, and 59-9 on pgs. 461, 462, and 463)To install and remove a chuck follow the instructions laid out in section 59-3 on pgs 462 and 463
22 LATHE CUTTING TOOLS, TOOLHOLDERS, CUTING SPEEDS, AND FEED SELECTION UNIT 60MetalworkTechnology and Practice
23 Tool Bits Defined: Cutting tools for lathes Types of Tool Bits Left Hand Turning ToolLeft Hand Facing ToolRight Hand Turning ToolRight Hand Facing ToolRound NoseRound Nose Turning ToolThreading ToolBoring ToolCut-Off ToolInside Turning Tool
25 Cutting Tool Terms Cutting Edge: The part that does the cutting Side Cutting EdgeEnd Cutting EdgeFace: Top Tool SurfaceFlank: Side of the tool below the side cutting edgeNose: Point of the toolNose Angle: Angle formed by the side cutting edge and the end cutting edgeNose Radius: The dimension of the arc that forms a round noseShank: Body of the tool
26 Cutting Tool Terms (cont.) Side Cutting Edge: The angle formed by the side cutting edgeEnd Cutting Edge: The angle formed by the end cutting edgeSide Relief: The angle between the tool flank and the original side of the toolEnd Relief: The angle between the end of the tool and a line drawn 90 degrees to the base of the toolholder
27 Cutting Tool Terms (cont.) Left hand cutting tool: Has cutting edge on the rightRight hand cutting tool: Has cutting edge on the left
28 ToolHoldersThe NCWHS lab uses a multiple tool post, tool holder system.The tool bit is inserted into a block where four tool bits can be utilizedLathe Tool Post Systems