Lathe Compontents And Operation Flashcards
When using a file on the lathe why is it important to use your left hand to hold the handle?
To avoid reaching over the lathe
What is the most typical lathe?
Engine lathe
General purpose machine that can do practically any machining jobs
What are the types of lathe centres?
Live centres - turns with the headstock
Solid dead centres - does not turn
Half centre - allows room for tool
Revolving dead centre - spins on bearings
What is a lathe dog for?
Transmit drive power from the spindle to a work piece.
What is more versatile 3 Jaw or 4 jaw chucks?
4 jaw chucks can hold irregular shapes and be set up more precise.
Tool holding systems must be?
Rigid
Adjustable
Repeatable
What is the purpose of a steady rest?
Provide support for long work pieces
What does a follower rest do?
Keeps work piece from
Deflecting from the cutting tool
Turning refers to?
Rotating a workpiece and reducing its diameter with a tool.
CS x 4 / D
CS x 320 / D
Formula for calculating spindle speed (RPM)
CS-cutting speed
D-diameter of material
- as work pieces get smaller the spindle speed must be increased.
How is feed rate measured?
Mm or inches per revolution
Finishing requires ______ feed rate?
Between .002 and .005 inches per revolution. Choose the highest feed rate that still produces and acceptable surface finish.
Right hand tools cut from?
Tail stock to headstock
What is the difference between direct and indirect reading dials?
Direct dials - each line on the dial represents .001” on the diameter of the work piece
Indirect dial - each line represents .001” on the radius of the work piece. So .001 actually equals .002” of material removed
When roughing a work piece it is important to leave _____” for finishing?
.030”
Feed rate should be as high as the cutting tool and machine can handle
Between .015 and .030
Use fewest roughing cuts as possible
Parting off hollow workpiece that is not true will result in?
Some tips to part off?
Broken tool
- part as close to chuck as possible
- set cutter with as little overhand as possible
- set spindle speed to half of your turning speed
- if tool chatters reduce the spindle speed
- never attempt to part between centres
How do you figure out cutting speed for drilling on a lathe?
Same as drill press
CS X 4 / DRILL SIZE
When using the lathe is it better to have long or short chips and why?
Short chips are better. Long chips can be dangrous
Lathe parts
Lead screw, feed rod and rack on a lathe?
Lead screw moves the carriage at a determined speed for threading
The feed rod moves the carriage at a slower rate suitable for turning.
Live centre
Driving between centres?
Fits in the headstock Must be used with a lathe dog to rotate
Old method before chucks were common to rotate work piece
Each jaw on a 4 jaw chuck moves independently. This allows a work piece to be adjusted until it runs true. What is the procedure?
1: set up headstock gear in neutral so it can be rotated
2: adjust each of the four jaws until they are at appropriate diameter
3: Insert piece and tight jaws lightly
4: place dial indicator against the workpiece at centre height. Plunger should be horizontal or vertical.
5: rotate chuck until # 1 jaw is inline with dial indicator. Set dial to 0
6: repeat this process using the #2 and 4 jaws. Spin the chuck
When is a spider attachment used?
Long tubular work piece requires a centre but the inside diameter is to large to run on a centre.
Why should you not use compressed air to clean the lathe?
Dangerous and can drive chips into places where they cannot get out.
Oiling of the ways, cross slide and taper attachment must be done when?
At the end of each day
Check lubrication pots everyday
Check headstock sight glass for oil level
Taper applications are :
- Cutting tool shanks
- wedges
- machine tool spindles
- tapered mandrels and arbours
- taper pins
- tapered gib keys
Metric tapers are expressed by a _____
Imperial tapers are expressed by ______
Taper ratio
Taper per foot TPF
Some key points about cutting speed are?
- spindle speed is set to the correct RPM to achieve the proper cutting speed.
- hardness of the workpiece material and the cutting tool affect the cutting speed. The harder the workpiece the lower the cutting speed, the harder the cutting tool the higher the cutting speed.
- cutting speed decreases as the workpiece gets smaller if the RPM remains constant. Spindle speed must be set higher for smaller work pieces.
- use slower cutting speeds for roughing cuts and higher speeds for finishing
- select slower speed to start and and increase as work allows
If you are setting depth of cut and you go past your mark what must you do to over come the backlash?
You must reverse wheel by at least a full turn and re attempt the correct setting. If you just back up to the mark it will not be accurate because of the backlash.
Finish cut gives a workpiece a smooth surface finish and and accurate size. Use the following technique for the finish cut:
1: rough workpiece to .030”
2: set the spindle speed for the maximum cutting speed for the material you are cutting
3: use highest feed rate that provides acceptable finish
4: use the cross feed dial to set a depth of cut to .015” and machine a diameter about 1/4” long
5: measure diameter with a micrometer
6: calculate how much material must be removed to produce the finished diameter. Set the Final Cut depth accordingly.
Proper depth for the centre drill?
Boring is when you machine an internal feature. Some key points are:
- Boring can only enlarge a hole, not start a tool
- use a drill slightly smaller than the final bore size.
- bores run perfectly true to the work piece. Drilling and reaming can only be done in nominal sizes.
Techniques to reduce chatter when boring?
- make set up as rigid as possible
- mount boring bar with the least amount of overhang
- if chatter occurs reduce the spinel speed and increase the feed rate until the chatter ceases.
- dampen the chatter by holding a piece of wood against the boring bar
- use carbide boring bits
When boring it is hard to know when to disengage the feed because you cannot see the tip of the cutter. Here are some helpful tips.
- Clamp a stop to the ways
- make a small mark on the boring bar to signify the end of its travel
- position a dial indicator on the ways of the lathe. So that the dial reads 0 when the carriage must be disengaged
When reaming holes use pre drill sizes smaller than 1/2 inch ream should be ______ smaller than reamer?
Larger 1/2 inch and larger should be ______ smaller than reamer?
1/64
1/32
Set spindle speed to half of drilling speed and twice the feed rate
Remove reamer before stoping the spindle. NEVER REVERSE ROTATION
Most dangerous operation on a lathe is?
The finishing process because your hands are so close to the rotating work piece.
- hold handle of file with left hand
- never use file without handle
- never use file on seal or bearing fits
- hold strip of emery with left hand under and right hand over
- do not hold emery in the same spot
- always be alert
- allow work piece to cool before measuring.
Two types of knurled are
Diamond knurl
Straight knurl
Knurl if should be done at?
- slow spindle speeds
- .010” feed for fine knurl .020” for medium knurl, .030” for course knurl
- knurling can increase diameter up to.030” diameter can be made slightly smaller before knurling if finish size is important.
When doing any filing or grinding on a lathe it is important to?
Protect the ways with plywood or cardboard.
Do not use rags
