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GENERAL GAUGES

Gauges for gauging pitch, gears, centres, angles, threads, chamfers, tapers & welds

Thread Pitch Gauges

Designed for measuring the pitch or lead of a screw thread

Feeler Gauges

For measuring gap widths or clearance between two parts

Welding Gauges

Measure wall thickness, alignment, crown height & weld length

Radius Gauges

Used to measure internal and external radius on a component

Chamfer Gauges

Designed for measuring both internal and external chamfers

Taper Gauges

For measuring slot widths or diameters of holes

Marking Gauges

Used to scribe a line parallel to the reference edge

Tape Measures

High tensile strength fibreglass tape with up to 50m length

Drill Gauges

Used for measuring angles on twist drills. Made from stainless steel for longer tool life and durability.

Gear Tooth
Gauges

For measuring <2000mm/80"

Centre Gauges

Check the angle of screw cutting inserts and centres

Angle Gauges

Designed for measuring an angle relative to a larger workpiece

General Gauges

 

What is a thread pitch gauge?

Thread pitch gauges are measuring instruments used to identify and check the pitch of a screw thread. Each leaf on a thread pitch gauge contains a different pitch, which the user would cycle between until the pitch of the gauge matches the pitch of the threaded object (e.g. bolt or screw). The pitch of each leaf will be etched onto the side of the leaf, meaning the user can quickly identify the correct pitch once matched up.

Thread pitch gauges cover a variety of thread forms and sizes including Metric 60°, Unified National (UN) 60° and British Standard Whitworth (BSW) 55°. Pitch for metric sizes is measured in mm whereas pitch for imperial sizes is measured in TPI (threads per inch). Leaf pictures range from 0.25mm up to 7mm or 4TPI to 62TPI.

 

What is a feeler gauge?

Feeler gauges are measuring instruments used to gauge or check the thickness or clearance of a gap between two closely positioned objects. The user would insert a leaf or leaves from the feeler gauge (that looks to have a similar thickness to the gap being measured) into the gap and move the gauge around until you feel contact on both sides of the gauge. In some circumstances, more than one leaf is needed to accurately calculate the thickness of a gap; all the user needs to do is sum up the total thickness of all feeler gauge leaves used. A practical example of using a feeler gauge is measuring the gap between the component and the table or vice bottom. This will give the engineer/user a good idea on how much taper the job has and how much the job needs to be traown in order to bring it back square.

Different feeler gauges have varying lengths and thicknesses depending on the type and size of the holes to be measured. Depending on the accuracy of the feeler gauge, thickness increments between leaves could be 0.1mm, 0.05mm or even 0.01mm in smaller sized gauges. Most engineers will use feeler gauges in their day-to-day operations due to its accuracy and ease of use.

 

What is a welding gauge?

A welding gauge is a measuring instrument which checks various features of a weld. It is a precision inspection tool which will only be used in very specific situations. Applications include measuring how much weld is present between two parts (fillet welding gauges) and measuring dimensions or alignment on a weld including weld prep angle, throat size, crown height and weld length. Engineers may need to check these dimensions to ensure a weld is strong enough and the correct size to withstand external forces or significant resistance acting against the weld.

Welding gauges come in a plethora of shapes and sizes which can, at first, seem daunting. The key criteria to determine which gauge is suitable is the size of the weld, the dimension which need measuring and the accuracy to which the measurements need to be to. Welding gauges are available with either analogue or digital output and are also supplied as sets containing various types of welding gauge including fillet welding gauges, pipe welding gauges and standard welding gauges as well as micrometers, inspection mirrors, magnifiers and rules.

 

What is a radius gauge?

A radius gauge is a measuring instrument designed to check convex and concave radii. Similar to feeler and thread pitch gauges, radius gauges feature a number of leaves which each have their own radius angle. This angle will be etched onto the side of each leaf for easy reference. The user would position a radius gauge leaf (the one which is closest to the estimated radius) against the edge of a workpiece or feature to be checked. It is recommended that a bright light source is placed behind the radius gauge so any difference between the gauge radius and measured radius can be easily identified. Only once there is contact against the full gauge face has the correct radius been found.

Accuracy and leaf radius are the two main contributors when deciding which radius gauge to choose. Leaf sizes on radius gauges can start from as small as 1mm and go up to 40mm and beyond. In most general workshop use, accuracy will not be of major concern as it is usually to 2 decimal places. For inspection-grade workshops, however, high accuracy radius gauges will be required.

 

What is a chamfer gauge?

Chamfer gauges are measuring instruments used to read off the size or height of an internal or external chamfer. They are supplied in either a fixed, analogue or digital format. The analogue and digital chamfer gauges utilise a sliding scale for a wider range of chamfer sizes to be measured, whereas the fixed model offers a more basic design which is less accurate. 45°, 30° and 60° chamfer sizes are available and both metric and imperial measurements can be taken by the digital model. Digital chamfer gauges also feature optional wireless data output capabilities.

 

What is a taper gauge?

A taper gauge is a measuring instrument designed for gauging slot, grooves or hole widths. Taper gauges can also be used to measure hole diameter, however correction on the reading will be needed due to the thickness of the taper gauge. Each gauge features a tapered design, meaning the gauge is slimmer (has a lower width) at the bottom than the top. To operate, the user would insert the taper gauge in the hole (thinnest side first) and push down until it can’t be pushed further. The user would then read the width value at the mouth of the hole, and this would indicate the actual width of the hole, slot or groove.

Taper gauges are available in either analogue or digital formats, with specific models designed for slots and bores. Different width taper gauges are also available depending on the size and depth of the hole to be measured. Digital taper gauges will usually offer the highest accuracy due to it being able to display measurements to multiple levels of decimal places, as well as it eliminating chances for human error.

 

What is a marking gauge?

A marking gauge (also known as a scribing gauge or scratch gauge) is used to mark or scribe lines on a workpiece. It can be used both on metal or wood surfaces and is traditionally used in joinery. Marking gauges have been commonplace in engineering for decades, with its earliest design featuring a pin sticking out of one end which would pierce the material to mark it. Whilst many marking gauges still feature this design, some modern designs don’t feature the pin and instead the user would mark a line using a pencil. This is especially true when marking metals where a pin wouldn’t make a noticeable mark.

Most marking gauges are used to scribe lines near the edge of a workpiece, as they feature an adjustable block which would rest at the workpiece’s side. However, a centre marking gauge can also be used to mark the centre of a round plate or shaft.

 

What is a gear tooth gauge?

Gear tooth gauges, or gear tooth pitch gauges, are used to check the module pitch of gear teeth. The module pitch is a standard by which all gear teeth are made to. Similar to feeler gauges and thread pitch gauges, gear tooth gauges are made up of several leaves which each contain a different thread pitch. The user would switch between each leaf until the pitch of the gear matches that of the gear tooth gauge leaf. Each gear tooth pitch is etched into the side of the corresponding leaf, allowing for easy matching of the correct pitch.

Each gear tooth gauge has a pressure angle (either 14.5° or 20° although other angles are available), which relates to the angle between the tooth face and the tangent line to the gear wheel. They are widely used by engineers due to their high accuracy and tough hardened stainless steel construction. Gear tooth gauges range from pitches as small as 0.35mm up to 12mm and beyond.

 

What is a centre gauge?

A centre gauge, also known as a fishtail gauge, is primarily used to check and set screw cutting tools. Screw cutting tools, also known as threading tools, single point threading tools or indexable threading tools, are used to make threads on a workpiece or feature. Centre gauges can also be used to check the angle of a screw thread and check a screw threads pitch. The gauge checks these dimensions through triangle shaped notches which are cut into the gauge at tight tolerances to accurately check the dimensions of a screw thread.

Centre gauge can be used to accurately measure screw threads of either Metric 60°, Unified National 60° or British Standard Whitworth 55° form. Most users of centre gauges will be hobbyist machinists or engineers who are making small batches of threaded parts. In large manufacturing situations, such thread checking procedures will be automated.

 

What is an angle gauge?

Angle gauges are quite self-explanatory as in they are used to check angles on a workpiece. An angle gauge will check the primary, complimentary and secondary angles. A secondary angle is also referred to as a ½ primary angle, as a secondary angle is always equal to ½ that of the primary angle. Depending on the type of angle gauge, it may only be possible to measure one type of angle, most commonly the complimentary angle. Angle gauge sets contain a variety of angle gauges which will all measure a different type of angle, for instance acute or obtuse angles.

Different types of angle gauges are available depending on the angles you are looking to get checked. Some are made up of several leaves whereas others are individual gauges.

 

What is a measuring tape?

Most people, even if they’re not from the engineering industry or even perform any form of DIY on a regular basic, will know what a measuring tape (or tape measure) is. It is a coiled flexible ruler made of either plastic, metal, fibre glass or cloth which extends from plastic housing to the required length. When the correct length has been found, you can use a clamping mechanism located on the plastic housing to lock the measuring tape in place so an accurate measurement can be taken.

Traditionally, tape measures will display both metric (mm) and imperial (inch “) measurements on each side of the tape’s width. Some will only include one measurement where the scale needs to be read more clearly. Tape measures can also vary in total length, depending on the required measuring range and size of the plastic housing. Most normal tape measures are 5m long, however 3m, 8m and larger sizes up to 50m are available.