Model Engineering Glossary

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Oak

The strongest and most durable wood that lasts for long periods in either wet or dry conditions.

See also: Timber.

Ohm's Law

A voltage of 1V (volt) across a conductor with a resistance of 1W (ohm) causes a current of 1A (amp) to flow through it.

V=IR

R=V/I

I=V/R

Oil

Used for lubrication.

A list of suppliers of all types is being prepared for inclusion here.

Oil Hardening Steel

Heat the steel to 770 to 800°C and soak at this temperature for ³/₄ hour per inch (25.4mm) thickness of material. Quench in a bath of oil inserting the heaviest end of the piece first (this way relieves stresses and reduces distortion). Further heat treatment at 100 to 120°C for a short while and then allowing the piece to cool naturally in air will reduce the stresses further and the possibility of cracking. Note: the higher the carbon content the lower the hardening temperature of steel.

Oscillating Steam Engine

This describes a particular valve system whereby the cylinder oscillates versus crank angle and this motion versus the main body of the engine forms the inlet and exhaust valve motion. This is a very simple way to form the valves, but does limit the valve timing adjustment.

The building of an oscillating engine.

Otto's Alloy

68.5 % Copper 31.5 % Tin

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