Elements 01

ANNEALING

Heating above the transformation range usually 1300º-1350ºF, and cooling slowly to soften the metal and increase in machining.

HARDENING

Heating above the transformation temperature and quenching usually in oil, for the purpose of increasing the hardness.

TEMPERING

Reheating to a temperature below the transformation range, followed by any desired rate of cooling to attain the desired properties of the metal.

STRESS RELIEVING

Heating to a subcritical temperature, about 1,100ºF-1,300ºF and holding at that temperature for a suitable time for the purpose of reducing internal residual stresses.

NORMALIZING

Heating to some 100ºF above the transformation range with subsequent cooling to below that range in still air at room temperature to produce uniform structure of the metal.

DRILLING MACHINE

A machine tool used for producing holes in metal by the use of a cutting tool called drill.

MILLING MACHINE

A machine tool used to form metal parts by removing metal from a workpiece by the use of a revolving cutter with many teeth, each tooth having a cutting edge which removes its share of the stock.

TOOL GRINDER

A machine tool used to sharpen or shape tools by using an abrasive wheel.

BORING MACHINE

A machine tools used to enlarge a hole by means of an adjustable cutting tool with only one cutting edge.

POWER SAW

A machine tool used to cut metal parts of light, medium, and large sections using a reciprocating hacksaw blade.

SHAPER

A machine tool used to machine flat or plane surfaces with a single point cutting tool.

PLANER

A machine tool used for production of flat surfaces on pieces too large or too heavy to hold in a shaper.

BROACHING MACHINE

A machine tool used to finish internal or external surfaces, such as holes or keyways by the use of a cutter called broach, which has a series of cutting edges or teeth.

BRONZE

An alloy of copper and tin.

BRASS

An alloy of copper and zinc.

ROLLING

The process of forming metal parts by the use of dies after the metal is heated to its plastic range.

FORGING

The process of forming a metal parts by the use of a powerful pressure from a hammer or press to obtain the desired shape, after the metal has been heated to its plastic range.

SAE 1320

A manganese steel containing approximately 0.20% carbon.

MILLING MACHINE

A machine tool in which metal is removed by means of a revolving cutter with many teeth, each tooth having a cutting edge which remove its share of the stock.

LATHE MACHINE

A metal tuning machine tool in which the work, while revolving on a horizontal axis, is acted upon by a cutting tool which is made to move slowly ( feed ) in a direction more or less parallel to the axis of the work ( longitudinal feed ).

PLANER

A machine tool used in the production of flat surfaces on pieces too large or too heavy or, perhaps to awkward hold in a shaper.

GRINDING

It consists of shaping a piece by bringing it into contact with a rotating abrasive wheel.

CALIPER

A tool used in measuring diameters.

DIAL INDICATOR

Used to true and align machine tools, fixtures, and works to test and inspect size trueness of finished work, and to compare measurements either heights or depths or many other measurements.

PLASTICITY

The ability of the metal to be deformed considerably without rupture.

LAYING OUT

The shop term used to include the marking or inscribing of center points, circles, arcs or straight line upon metal surfaces, either curved or flat, for the guidance of the worker.

REAMING

An operation of sizing and finishing a hole by means of a cutting tool having several cutting edges.

COUNTERSINKING

The operation of making a cone-shaped enlargement of the end of a hole, as for a recess for a flat head screw.

BORING

The operation of enlarging a hole by means of an adjustable cutting tool with only one cutting edge.

PITCH CIRCLE

An imaginary circle passing through the points at which the teeth of the meshing gears contact each other.

CARRIAGE BOLT

A type of bolt intended for use in boiling wooden parts together or wood to metal. It has a short portion of shank just underneath a round head, which is designed to keep the bolt from turning in the wood when the nut is tightened.

DIAMETRAL PITCH

The number of teeth per inch of pitch diameter and which gives some indications of the size of the gear teeth.

CIRCULAR PITCH

The distance from the center of one tooth of a gear to the center of the next consecutive tooth measured on the pitch.

ADDENDUM

The portion of a gear tooth that projects above or outside the pitch circle.

DEDENDUM

The portion of the gear tooth space that is cut below the pitch circle and is equal to the addendum plus the clearance.

GEAR RACK

When meshed with a gear, it is used to change rotary motion reciprocating motion.

WORM GEARS

A kind of gears used for heavy duty works where a large ratio of speed is required and are extensively used in speed reducers.

BEVEL GEARS

A kind of gears used to transmit motion from one shaft to another shaft at an angle to the first.

NORMALIZING

The uniform heating of steel above the usual hardening temperatures, followed by cooling freely in air.

QUENCHING

The operation of cooling a heated piece of work rapidly by dipping it in water, brine or oil.

ANNEALING

A method used in softening a piece of metal that is too hard to machine and is done by heating steel slowly above the usual hardening temperature, keeping it at the heat for ½ to 2 hours, then cooling slowly preferably in a furnace.

TOLERANCE

The total permissible variation in the size of a dimension, the difference between the limits of size.

SQUARING

The operation of machining the end of a workpiece to make the end square with the axis.

BACKLASH

The clearance between the tooth profiles of a gear tooth.

DIVIDING HEAD

A mechanism which usually do the indexing in a machine tool.

ABRASIVE

A material that can wear away a substance softer than itself.

TAP

A cylindrical bar of steel with threads formed around it and grooves or flutes running lengthwise in it, intersecting with the threads to form cutting edges. It is used to cut internal threads.

FEELER GAGE

A set of gages consisting of thin strips of metal of various thickness mounted in a steel case or holder and is widely used for measuring and checking clearances.

SLOTTER

A machine tool which is very similar to a shaper except that the ram reciprocates vertically rather than horizontally.

SHAPER

A machine tool used principally to machine flat or plane surfaces with single point cutting tool.