Parallel: Parallel means the same distance apart at all points.

 

Parallel dimensioning: Parallel dimensioning uses the same datum for a starting point. It reduces the chance of accumulating a tolerance error.

 

Parallel line development : Parallel lines are lines that run alongside each other. They are always an equal distance apart. How ever long you draw them, parallel lines will never meet or cross each other.

 

Parallelogram: A parallelogram is a four-sided 2D shape with opposite sides parallel.

 

Part section: A method of showing internal detail for one small section of a drawing only.

 

Pattern making: Pattern making is the process of creating a 2D map of a 3D shape to be formed.

 

Patterns: Patterns are 2D maps of 3D shapes.

 

Pencil: A pencil is a wooden sheath with a carbon based filler. They are used for drawing lines on paper or plastic drafting film.

 

Percentage: Percentage is a fraction or ratio with denominator of 100. It is usually denoted using the percent sign '%'. For example, 0.40 or 4/10ths equals a percentage of 40%.

 

Perimeter: The perimeter is the distance around a 2D shape.

 

Perpendicular: Perpendicular refers to a line or plane which meets another line or plane at right angles - in other words, standing at right angles to the plane of the horizon.

 

Perspective drawing: Perspective drawings show objects so that they appear proportionately smaller with distance (like the real object appears). They are also called pictorial projections.

 

Photocopier: A photocopier uses light reflected from the original drawing to make a copy. The advantage of photocopiers is that copies of engineering drawings can be made on transparent sheets as well as paper.

 

Pi: Pi, or , is the mathematical constant equal to a circle's circumference divided by its diameter. It is approximately 3.14159, which is usually rounded down to 3.14.

 

Pictorial projection: Pictorial projections show objects as they are 'seen' in the real world. They are also called perspective drawings.

 

Pinch rolls : Pinch rolls have one or two rolls that are used to preset the ends of any given cylindrical shape.

 

Pitch circle diameter: The pitch circle diameter is the diameter of a circular component that is to be manufactured. This circular component often has holes drilled into it. It can also be modified in other ways.

 

Plasma: Plasma is very hot gas. It is produced when gas is boosted to extremely high temperatures. Heat breaks apart the gas molecules, the atoms split causing the electrons begin to collide with each other and release vast amounts of energy.

 

Plasma cutter: A plasma cutter is used to cut steel and other electrically conductive metals. At the cutter's tip, a high-voltage arc is combined with compressed gas which creates plasma. This melts a small section of the metal. The force of the plasma flow makes a clean cut with little or no slag. The plasma arc travels through the nozzle of the cutter at a speed of over 6000 metres per second, and at temperatures over 16,000° C. This is what gives plasma its cutting capability.

 

Plasma cutting: Plasma cutting is a method used to cut steel and other electrically conductive metals.

 

Plotter: A plotter is a machine used for printing drawings. The two most common types of plotters are pen/pencil plotters and electrostatic plotters.

Pen/pencil plotters move a pen or pencil across a drawing sheet like a draftsman would to create a drawing. They are just faster!

Electrostatic plotters use a series of dots closely spaced together to draw the lines for engineering drawings.

 

Plug weld: A plug weld is where two plates overlap and where one of those plates has holes cut or drilled in which the weld process is placed to join the plates together.

 

Plus: 'Plus' is another way of saying 'add' when two or more numbers are combined to make a total. '7 plus 3' is the same as 'add 7 to 3'.

 

Points of tangency: The points of tangency are the marks drawn on each axis when drawing a radius. A tangent point (point of tangency) is the exact point where a straight line intersects with a curve or circle.

 

Presetting: Presetting means to set beforehand, for example, preset a cutting tool. Presetting is important when forming cylindrical or conical shapes because it ensures a well shaped, uniform final product.

 

Press blade: A press blade is the top forming tool in a press brake to bend any given metal to any given angle.

 

Press brake: A press brake is a machine that forms straight line bends in sheetmetal and plate. Also called a brake press.

 

Pressing sequence: The pressing sequence is the order in which an object is formed on a press brake.

 

Prism: A prism is a solid figure which has bases (or ends) of the same size and shape and that are parallel to one another, and where each side is a parallelogram.

 

Profile cutter : Projection lines are thin continuous parallel lines that project out from a drawing to help describe a component. They are drawn two at a time with a dimension and a dimension line between them.

 

Projection lines: Projection lines are thin continuous parallel lines that project out from a drawing to help describe a component. They are drawn two at a time with a dimension and a dimension line between them.

 

Projection symbol: A projection symbol is used with a projection line to communicate information about a component.

 

Pyramid rolls: Pyramid rolls are machines comprised of three rollers, through which metal is passed in order to produce a curve or bend in the material.

 

Pythagoras' theorem: Pythagoras' theorem is that in any right triangle, the area of the square of the hypotenuse is equal to the sum of areas of the squares of the other two sides.

It is expressed as the equation a² +b² = c².

The equation means that if the lengths of any two sides of a triangle are known, the length of the third side can be calculated.