Chapter 23 Flashcards
Turning
The process of machining external cylindrical and conical surfaces.
Taper turning
Tool is fed at an angle to the axis of rotation
Facing
Tool is fed to the axis of rotation
Form turning
Using a tool with a specific form that leaves the same shape on the workpieces.
Parting or cutoff
The workpiece is cut into two
Boring
Produces internal cylindrical or conical surfaces
For turning
Do an initial cut, then a rough cut
Speed v is
Feet per minute
Feed rate
fr is inches per revolution
Depth of cut
d is in inches
Boring
The enlarging of an existing hole. Since the tool overhang will be greater, smaller deeds and depths of cuts may be selected to reduce vibration and chatter.
Facing
Facing is the producing of a flat surface as the result of the tool being fed across the end of the rotation workpiece. Should be fed at a proper uniform rate.
Parting
The operation by which one section of the workpiece is separate from the remainder, cut off. Tool is fed perpendicular.
Drilling
When drilling deep holes, remove the drill to allow chips to exit, this is peck drilling.
Bed of lathe
Base and backbone of lathe. All basic components are mounted here.
Ways of lathe
Are on top of the bed.
Headstock
Provides lowered means to rotate the work at various rpm values. It consists of a hollow spindle and a set of transmission gears.
Spindle
Carries the headstock. Has a hole in which large bar stock can be fed through. Contains means for mounting types of work holding devices.
Tail stock consists of
1 a lower casting fits in the inner ways of the bed and can slide longitudinally. 2 an upper casting fits on the lower one and can be moved transversely. 3 the quill, contains a Morse tapper.
Quill
Cutting tools or a lathe center are held here
Carriage assembly
Provides the means for mounting and moving the cutting tools
The carriage
Rides on the outer set of the ways.
Cross slide
Provides a means for moving the lathe tool in the facing direction.
Compound test
Tool post mounted here.
Apron
Had the controls for providing manual and powered motion for the carriage and powered motion for the cross slide.
Feed rod
Provides powered movement of the carriage and cross slide
Lead screw
Used for cutting threads. A split nut is closed around the lead screw
Quick change gear boxes
Driven by the spindle, connect the feed rod and lead screens
Turret lathes
Hexagon turret replaces tailstock. The turret holds six tools and can be rotated for the tool of need. The square turret on the cross slide can bring each of the four tools into operating position.
Ram type turret lathe
Tam and turret are moved up to the cutting positions by means of the capstan wheel and power feed is engaged.
Saddle type turret lathe
Main turret mounted on saddle. A pilot arm may be used for extra rigidity.
Two types of single spindle screw machines
American Brown and sharpe, other is Swiss type.
Brown and sharpe screw machines
Designed for bar stick with a main turret mounted. All motions of the turret controlled by cams. The turret cam defines the movement of the turret. These have a feature that locks up the workpiece after kt is cut, and carries it to a position for secondary work.
Swiss type automatic screw machine
Most machining done with single point cutting tools. Not good for machining small parts
Lathe cutting tools
Most lathe operations are done using single point cutting tools. Because took materials are expensive, it’s desirable to use as little as possible. Inserts may be used for higher cutting speeds.
Lathe centers
Workpieces that are relatively long are usually held between centers. Two lathe centers used, ine in the spindle hole, and the other hole in the tailstock quill.
Two types of lathe centers
Dead and alive. Dead centers are solid and they have a Norse taper on one end.
Lathe dog and dog plate
Dog is clamped to the work. The tail of the dog enters a slot in the dog plate which is attached to the lathe spindle in the same manner as the lathe chuck.
Lathe centers
Before a workpiece can be held between lathe centers a center hold must be drilled first.
Lathe chucks
Support a wide variety of workpieces.
Two types of chucks
Three jaw and four jaw
Three jaw chucks
Used for work that had a round or hexagonal cross section. Will provide automatic centering.
Four jaw chuck
Each jaw can be moved inward and outward independently through the use of chuck wrench. Support a variety of workpiece shapes, and can be used for heavy duty work.
Collets
Used to hold smooth cold roller bar stock or machines workpieces more accurately than with regular chucks. For a variety of symmetrical shapes.
Collets only used on
Drill rod cold rolled extended or previously machines stock.
