Metal Exam Flashcards
When using the lathe, how much stock can be protruding from the chuck?
No more than twice the diameter.
When cutting the face off stock, where do you start and end?
You start cutting from the center to the edge
What are the main reasons for knurling a piece of work?
The main reasons are to make a hand grip, improve the appearance of the surface, and increase the diameter of a workpiece.
What is the spindle speed formula?
Pie * diameter * RPM / 12
What is the formula for calculating spindle RPM?
Cutting speed * 4 / Diameter
For lathing, what is the feed rate?
The feed rate is how far the tool bit advances with each revolution of the work piece.
When making a rough cut on the lathe it requires a ____ _____ ____.
Faster feed rate
When making a finishing cut on the lathe it requires a _____ _____ _____.
Slower feed rate
For lathing, what is the depth of cut?
How far the tool bit advances into the stock material.
What is a common use for parallels?
Parallels are used to space work above the bottom of the vice; parallels are used for precision and close tolerance when milling or drilling stock.
There are several angles ground on a lathe tool which provide the necessary shape for efficient cutting. The angles used depend on:
1) The hardness of the material being cut.
2) The rigidity of the lathe.
3) The amount of metal to be removed each cut.
4) The quality of finish required.
For a lathe bit, when the tool angle is large (NOT a knife edge), the tool:
1) has maximum strength
2) provides good heat dissipation
3) requires more power to cut
For a lathe bit, when the tool angle is smaller (sharper edge), the tool:
1) has a weaker cutting edge
2) machines a good finish
3) gives little tearing
4) cuts easily
What is the purpose of a relief angle on a lathe bit?
Relief angles ensure that only the cutting edge contacts the work. If a relief angle is not
correct, the side or end of the tool will rub, preventing the sharp edge from doing its job.
What is the purpose of rake angles on a lathe bit?
Rake angles help the material slide away from the work as it is cut off.
What is the purpose of side and end cutting angles for lathe bits?
Cutting material; Side and End cutting angles are usually not critical, but allow you to approach the work from
various orientations.
What is the angle for a center drill?
60 degrees
How is the depth measured when using a center drill?
It is measured to the shoulder.
What are all the main components of a drill bit?
Chisel point, cutting edge, flute.
What is the typical metal drill angle?
118 degrees.
What is the critical temperature when heat-treating steel? And what indicates this temp?
790-830 C is the critical temp, and it is indicated when the steel is a bright cherry color and non-magnetic.
In order for steel to be heat-treatable, how much carbon content must it have?
0.65%
Steel may be brittle after hardening, what is a method that can strengthen it after hardening?
Tempering to a particular temperature and quenching it again.
When tempering knives and chisels, what should the color and temperature be?
Dark blue; 300 C
