Model Engineering Glossary

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Sal Ammoniac

Chemical name: Ammonium chloride

Chemical formula: NH₄Cl

See also: Chemical Table.

Saturated Steam

Steam at the same temperature as the boiling point of water at that particular pressure is said to be saturated.

Scale

The fractional difference between the size of the model and the real model.

Shareware that has a number of features to allow you to calculate sizes given a scale Quickscale.net

Screws

See also: Threads.

Search for woodscrew books on Amazon.co.uk

Series Motor

• Easy starting
• Powerful starting torque
• Speed depends on load
• May run away if left to run free

See also: Electric Motors.

Search for electric motor books on Amazon.co.uk

Sheet Metal

The traditional way of defining the thickness of sheet metal has been the Birmingham Sheet Metal Gauge.

Shunt Motor

• Easy starting
• Speed reasonably independent of load
• Easy to regulate

See also: Electric Motors.

Silicon

After carbon silicon is the most abundant element on earth. Silicon is obtained by reducing sand (silica: SiO₂), with carbon.

Silver bromide

Chemical formula: AgBr

See also: Chemical Table.

Silver Bronze

64.46 % Copper 12.41 % Zinc 1.14 % Aluminium 4.77 % Silicon 17.19 % Manganese

Silver Nitrate

Chemical formula: AgNO₃

See also: Chemical Table.

Silver Steel

The word "silver" in the name comes from the appearance of this high carbon steel manufactured to BS 1407.

Slaked Lime

Chemical name: Calcium hydroxide

Chemical formula: Ca(OH)₂

See also: Chemical Table.

Soda Ash

Chemical name: Hydrated sodium carbonate

Chemical formula: Na₂CO₃ 10H₂O

See also: Chemical Table.

Sodium

Sodium is a soft, silvery coloured metal which, like other members of the alkali group of metals, is extremely reactive. more......

Soot

Chemical name: Amorphous carbon

Chemical formula: C

See also: Chemical Table.

Sorels Alloy

10 % Copper 80 % Zinc 10 % Iron

Specific Heat Capacity

The amount of heat required to raise unit mass of a substance by one degree.

Specific Volume

The volume occupied by a unit mass of a substance. This is the reciprocal of density and the units as such would be m³/kg.

Sphere

See also: Conversion of Units.

Spirits of Salts

An old name for Hydrochloric acid.

Stainless Steel

A range of stainless steels are available that have varying degrees of resistance to corrosion, containing between 8 and 25% Chromium. Other elements used in Stainless Steel are Nickel and Niobium.

Search for stainless steel books on Amazon.co.uk

Stannic Oxide

Trade name: Tinstone

Chemical formula: SnO₂

See also: Chemical Table.

Stannous Chloride

Chemical formula: SnCl₂ 2H₂O

See also: Chemical Table.

Staybrite

8 % Nickel 74 % Iron 18 % Chromium

Steel

An alloy of iron and carbon. Mild steel contains less than 0.15% Carbon and hard steel more than 0.3% Carbon. more......

See also: Colour Temperatures, Currie Point, Oil Hardening Steel.

Search for steel books on Amazon.co.uk

Sterling Silver

Silver with 7.5% copper.

Stirling Engine

An external combustion engine. Also known as a Hot Air Engine. The Stirling engine was invented in 1816 by a Scotch clergyman, Robert Stirling, as a competing technology to the steam engine. Stirling engines work by subsequently heating and cooling a gas inside a closed volume. As the gas is heated it expands and as it is cooled it contracts. This expansion and contraction works forces a working piston which in turn drives a crankshaft. A Stirling cycle has two pistons: one that drives the crankshaft known as the power piston and one that moves the gas between the hot and cold ends of a cylinder known as the displacer piston.

See also: Fizgig - Stirling Engine, Low Temperature Striling Engine (Gallery).

Sulphuric Acid

Chemical formula: H₂SO₄

See also: Chemical Table.

Super Dural

4 % Copper 93.75 % Aluminium 1.25 % Silicon 0.5 % Manganese 0.5 % Magnesium

Super Glue

More correctly known as cyanoacrylate.

Search for glue books on Amazon.co.uk

Superheated Steam

Steam taken directly from a boiler retains the same temperature and pressure as when it was produced and is said to be "saturated". By taking such steam and heating it further, a much greater volume of gas can be produced for a small amount of extra heat. Tests have shown that superheating can result in a 25% economy in coal and 30% in water. Introduced in the 1900's and used mainly on the larger main-line engines. Superheated steam will always be dry.

Search for steam table books on Amazon.co.uk

S.W.G. British Imperial Wire Gauge

This is a numbering system for wire diameter. more......

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z