A page to bring together all of the measurement instruments and techniques that we use in model making and model engineering.

Absolute Measurement – a measurement made without a direct reference to a second signal or measurement.

Dial Test Indicator – used to align and centre parts in the lathe among lots of other uses.

The dial gauge is an alternative and it gives a larger full-scale range of operation, typically around 1/2 inch or 12.5mm – using a dial gauge to machine a backplate and setup a new chuck.

Digital Calipers – the modern digital caliper allows you to measure: outside, inside and depth. The latest large face calipers are easy to use.

Moore and Wright digital caliper
Moore & Wright Digital Caliper (MW110 review)

Direct Measurement – a process of obtaining the measurement of some entity by reading a measuring tool, such as a ruler for length, a scale for weight, or a protractor for angle size.

Digital Micrometer – micrometer with a digital readout. Do I need one?

Sieg SX2.7 and Machine DRO

DRO’s – Digital ReadOut – digital readout system on a machine tool. These are often suppled as kits, such as the universal kit from Machine DRO. Here we fit this to the Sieg SX2.7 milling machine.

engineers square

Engineers Square – used to accurately mark a line at 90° to another. Fundamental tool used in marking out.

Measurand – a physical quantity, force, property or condition which is to be measured.

Measurement – the collection of quantitative data.

Metrology – the science of dimensional measurement; sometimes includes the science of weighing.

Micrometer – very accurate thickness and diameter measurement.

optical centre punch

Optical Centre Punches – allows you to line up the punch very accurately on the workpiece. Using a holder that you initially drop the optical centre into to align the holder, then you remove the optical centre and replace it with a hardened steel centre that is tapped with a hammer to mark the position.

Coterminal Angles

Plane Angles – the plane angle between two radii of a circle which cut off on the circumference an arc equal in length to the radius. The secondary SI unit for the plane angle is the radian.

The inclination of one line to another. One complete revolution equals 360° (degrees) or 2π radians.

Pressure and it’s Units – defined as the force exerted per unit area. The SI unit of pressure is the pascal or newton per square metre.

Rulers – you need to be aware of parallax when using any manual measurement system and this includes a rule.

The Incra rule allows you to accurately mark through the ruler itself.

Scale – model scale and sizes cover a wide range.

car boot find snug

Snug – the joints found on a magnetic base that is used to position a DTI or Dial Gauge.

vernier caliper

The vernier caliper provides the three basic functions of inner, outer and depth gauge. In all cases the measurement is read from the same vernier scale.