I have been reading other material as well, these notes are from the U.S. Army Machining Course at http://opensourcemachine.org/us-army-courses.

NOTES FROM US ARMY MACHINE COURSES

FUNDAMENTALS OF MACHINE TOOLS

CHAPTER 1
INTRODUCTION TO THE MACHINE SHOP

MACHINE SHOP WORK

SCOPE
Work in a machine shop includes all cold-metal work by an operator using hand tools or power tools for the removal of material to a specified shape or form. This does not include sheet metal work or coppersmithing.

LAYING OUT WORK
Laying out is a shop term, it means to scribe lines, circles, centers, and so forth on the surface of material that serves as a guide in making the finished work piece. These lines must be scribed out with the greatest accuracy or the part will be of no use.
SCRIBING LINES OF METAL
Layout dye is used in the scribing of lines on metal, it is blue in color, and provides excellent contrast between metal and the layout lines. Before applying the dye clean the work surface of all oil and grease or the dye will not adhere to the metal.
COMMON LAYOUT TOOLS
SCRIBER: A scriber is the layout tool used to produce lines, it is made of hardened steel and is kept clean by honing on an oilstone.
DIVIDER: A divider is used to layout circles, arcs, and radii. The legs of the divider must be kept shape, and to the same length. Use a steel rule in setting the needed dimension to be scribed on a work piece.
TRAMMEL: When circles, arc, and radii are to large to use a divider a trammel is used. The trammel is made up of three parts: a beam, two sliding heads with scriber points and an adjusting screw
HERMAPRODITE CALIPER: IS A TOOL USED TO LAY OUT LINES PARALLEL WITH THE EDGES OF A WORKPIECE. Also it can be used to locate the center of an cylindrical shaped work piece.
SURFACE GAGE: Has many uses and is most often used for layout work, it can scribe lines at any distance parallel to the work surface. A square and a surface plate are needed to set the surface gage at the desired dimension
Surface Plate; Provides a true smooth pane surface, from which dimensions are measured, usually they are made of granite.
Vernier Height Gage: The height gage is a special caliper on a special foot block for use on a surface plate. Common sizes are 10, 18, and 24 inches. It uses various attachments to scribe lines; a dial indicator can be mounted to make precision measurements.

Combination Square Set: is used in a number of layout operations. The square consists of a blade, square head, protractor and center head. Here the that parts that make up a square set.
The Blade is designed to allow different heads to slide along the blade and be clamped in any desired location.
The Square Head is designed with a 45 and 90 degree edge and can be used as a try square and miter square as well as a depth rule. With a split level in the head it can also be used as a square.
The Protractor Head has a revolving turret graduated in degrees from 0 to 180 of to 90 and can be used to lay out and measure angles to and accuracy of 1 degree.
The Center Head is used to locate and layout the center of cylindrical workplaces.


Bevel Protractor has an adjustable blade with an graduated dial, the dial is marked out in degrees through a complete circle of 360 degrees
STEPS IN MAKING A LAYOUT
o Study the shop drawing or blueprint before cutting off stock, allow enough material to square the ends if required.
o Remove all grease and oil from the work surface and apply layout dye.
o Locate and scribe a base line, all measurements are made from this line. If the work piece has one true edge that can be used as a base line.
o Using the base line as a reference line, locate and scribe all center lines for each circle, radius of arc.
o Mark the points where the center lines intersect using a sharp prick punch.
o Scribe all circles, radii and arcs using a divider or trammel.
o Using the correct type protractor, locate and scribe all straight and angular lines.
o Scribe all lines for internal openings.
o All layout lines should be clear, sharp and fine, reapply layout dye to all messy, wide, or incorrect lines and rescribe.
JIGS AND FIXTURES
Aid in the manufacturing of parts, accurate and interchangeable.
MECHANICAL DRAWINGS AND BLUEPRINTS
Mechanical drawings are made with special instruments and give a true representation of the object to be made, including size, description, material used, and method of manufacture.
WORKING FROM DRAWINGS
A detail print shows the individual part to be made, with two or more orthographic (straight-on) views of the part, and in some cases shows an isometric projection. An isometric projection shows what the part will look like when complete. Every drawing has a number, and a title box which shows the part name, the scale used, the pattern number, and the material required. Also shown is the assembly or subassembly print number to which the part belongs, the job order number the quanity and the date of the order. Along with the name of the person who drew, checked and approved the drawing. Building a part to the print depends on the following:
o Correctly reading and observing all the data on the drawing.
o Using the correct tools and instruments for laying out the job.
o Using the baseline method of locating the dimensional points during the layout.
o Observing all tolerances and allowances
o Accurate measuring of part throughout the fabricating process
o Allowing for expansion of the work piece by heat generated by cutting and machining operations
Limits of Accuracy

Properties, Identification, and Heat treatment of Metals
GENERAL
METAL CLASSIFICATION
Metals are ferrous or nonferrous, iron being the main element in a ferrous metal. A metal can contain less than 50% iron if it contains more iron than any other metal.
FERROUS
Ferrous metals include cast iron, steel and various steel alloys. The only difference between iron and steel is carbon content. Cast iron has more than 2% carbon, while steel has less than 2%.