Macadam
Paving surface material for driveways and roads, comprised of small compacted pieces of stone. It was invented by John McAdam who combined it with tar to make Tarmac. An asphalt binder was added, and the resulting product, called Tarmacadam, was used frequently approximately 50 years ago.

Machine
A structure which is made of a framework and assorted fixed and moving parts to transmit motion or energy from one part to another, as it's used for doing some kind of work. A mechanism.

Machine Bolt
Hexagonal headed male fastener with threads that fit in a machine threaded part or a nut for assembly purposes.

Machine Brazing
Brazing, which is a process of bonding metals together by use of an additional metal that melts at a higher temperature than 840 degrees F and lower than the melting point of the metals being joined, by use of an automatic or operator controlled heat application, often with a brazing filler metal feed. Machine brazing is often more consistent.

Machine Screw
Indented head, male fastener with threads that fit in a machine threaded part or a nut for assembly purposes. They can have either Phillips heads or slotted heads.

Machine Shop
Factory where powered tools and machinery to shape, cut, smooth, etc. are used to manufacture items out of metal.

Machine Tool
Powered tool, which is used on metals or other materials to cut, grind, shape, etc.

Machine-tooled Finish Limestone
Limestone blocks with a grooved finish of four to eight parallel grooves per inch, which are used for decoration.

Machine Weld
Faster and more exact than manual welding, these metals are fused together by melting at the surface to be joined and by the addition of filler metal.

Machinery
1. A combination of things, which keep something in action.
2. The working parts of any machine.
3. More than one machine.

Macro
Meaning long, large or expanded and is used often as a prefix to a term to point out the large, expanded use of the term.

MACRS
see Modified Accelerated Cost Recovery System.

Madison Clips
Thin metal clips which are used in older work places to attach switches and receptacles.

Magnesium
Light weight, strong and bendable this silver white metallic chemical element is used in making several alloys, one of which is used to tall ladders. It burns with a hot white light making it usable in flashbulbs, etc. Atomic symbol Mg. Atomic Number 12. Atomic weight of 24.312. Melting point 651 degrees C. Boiling point 1107 degrees C.

Magnet
Material containing the property of attaining iron or steel and also produces an exterior magnetic field of energy.

Magnet, Permanent
An iron type of material, which retains the magnetism, it has been given rather than requiring electrical power to maintain a magnetic field.

Magnetic Cylinder Lock
Lock cylinder that has magnetic pin in a plug keeping the lock closed. When a key has magnetic inserts that match the polarity of the pins, the pins move out of their slots due to being repelled by a like magnetic pole, making the lock open.

Magnetic Energy
The ability to attract iron or iron compounds.

Magnetic Field
A region of space, around a magnetic body, in which you can detect an appreciable magnetic force.

Magnetic Starter
Starter with an electromagnet to open and close the circuit of an electric motor. By use of a manual mechanical switch between the starter and the power supply, the power going to the motor can be interrupted if the magnetic starter fails in the closed position.

Magnetic Stud Finder
Mechanism, consisting of a magnetic indicator, which locates wall studs by detecting the nails or screws that were used in installation.

Magnetized Hammer
Hammer consisting of a magnetized head, which holds the nail, making it possible to keep the other hand free to hold the material.

Magneto
Electric generator using permanent magnets to create a flux field, which is an area of magnetic lines of force cut by a rotating armature to generate electricity.

Mahogany
Hardwood coming from any of the trees of the mahogany family, especially the hard reddish-brown to yellow wood of the tropical American tree, which is used for furniture, interior trim and finish and cabinets. Both solid and veneer forms of this wood are used.

Mahogany, Philippine
Tropical wood that is coarser and softer than mahogany, which it strongly resembles. Is most often used as veneer plywood on interior doors but is also usable for furniture and cabinets.