Types of Mechanical Gauges

Ruler and scales: They are used to measure lengths and other geometrical parameters. They can be single steel plate or flexible tape type tool.

Calipers: They are normally of two types- inside and outside caliper. They are used to measure internal and external size (for e.g. diameter) of an object. It requires external scale to compare the measured value. Some calipers are provided with measuring scale. Other types are odd leg and divider caliper.

Vernier caliper: It is a precision tool used to measure a small distance with high accuracy. It has got two different jaws to measure outside and inside dimension of  an object.It can be a scale, dial or digital type vernire caliper.

Micrometer: It is a fine precision tool which is used to measure small distances and is more accurate than the vernire caliper. Another type is a large micrometer caliper which is used to measure large outside diameter or distance.

Feeler gauge: Feelers gauges are a bunch of fine thickened steel strips with marked thickness which are used to measure gap width or clearance between surface and bearings.

Telescopic feeler gauge: It is also known as tongue gauge and it consists of long feeler gauge inside a cover with tongue or curved edge. The long feeler strips protrude out of the cover so that it can be inserted in to remote places where feeler gauge access is not possible.

Poker gauge: This gauge is used to measure propeller stern shaft clearance, also known as propeller wear down.

Bridge gauge: Bridge gauges are used to measure the amount of wear of Main engine bearing. Normally the upper bearing keep is removed and clearance is measured with respect to journal. Feeler gauge can be used to complete the process.

Liner measurement tool: Liner measurement tool is a set of straight assembled rod with marked length in each set. It is used to measure the wear down or increase in the diameter of the engine liner.

American Wire Gauge: American wire gauge or AWG is a standard tool which is circular in shape and has various slots of different diameter in its circumference. It is used to measure cross section of an electric cable or wire.

Bore Gauge: A tool to accurately measure size of any hole is known as bore gauge, It can be a scale, dial or digital type instrument.

Depth gauge: A depth gauge is used to measure the depth of a slot, hole or any other surface of an object. It can be of scale, dial or digital type.

Angle plate or tool: It is a right angle plate or tool used to measure the true right angle of two objects joined together.

Flat plate: Flat plate is a precised flat surface used to measure flatness of an object when it is kept over the flat plate.

Dial Gauge: Dial gauge is utilized in different tools as stated above and can be separately used to measure the trueness of the circular object, jumping of an object etc.

Lead Wire: It is a conventional method to used soft lead wire or lead balls to measure the wear down or clearance between two mating surfaces. The lead wire or balls of fixed dimension is kept between two surfaces and both are tightened against each just as in normal condition. The increase in the width of the lead wire or ball will shoe the clearance or wear down.

These are some of the main tools that are used on board ship. If you feel we have missed any important tool, then let us know and we will add it in the list.

Snap Gauges: snap gage is a form of Go/no go gauge . It is a limit gage with permanently or temporarily fixed measurement aperture(s) (gaps) which



Three different sets of threading gauges: A thread pitch gauge, also known as a screw pitch gauge or pitch gauge, is used to measure the pitch or lead of a screw thread. The uppermost gauge in the image is an ISO metric pitch gauge, the larger gauge in the center is for measuring the Acme thread form, and the lower gauge is for Whitworthscrews.

Thread pitch gauges are used as a reference tool in determining the pitch of a thread that is on a screw or in a tapped hole. This tool is not used as a precision measuring instrument. This device allows the user to determine the profile of the given thread and quickly categorize the thread by shape and pitch. This device also saves time, in that it removes the need for the user to measure and calculate the thread pitch of the threaded item.



profile gauge or contour gauge is a tool for recording the cross-sectional shape of a surface. Contour gauges consist of a set of steel or plastic pins that are set tightly against one another in a frame which keeps them in the same plane and parallel while allowing them to move independently, perpendicularly to the frame. When pressed against an object, the pins conform to the object. The gauge can then be used to draw the profile or to copy it on to another surface.


Profile gauges are used widely in metalworking and woodworking. In architectural conservation, they are used to document the profiles of decorative moldings. In archaeological illustration, they are typically used to record the profile of pots, and are thus named pottery gauges; but in ceramics, a pottery gauge is a template used in making pots.




gauge block (also known as a gage blockJohansson gaugeslip gauge, or Jo block) is a precision ground and lapped length measuring standard. Invented in 1896 by Swedish machinist Carl Edvard Johansson, they are used as a reference for the calibration of measuring equipment used in machine shops, such as micrometers, sine bars, calipers, and dial indicators(when used in an inspection role). Gauge blocks are the main means of length standardization used by industry.



ring gauge, or ring gage, is a cylindrical ring of steel whose inside diameter is finished to gauge tolerance and is used for checking the external diameter of a cylindrical object.

Ring gauges are used for comparative gauging as well as for checking, calibrating, or setting of gauges or other standards. Individual ring gauges or ring gauge sets are made to variety of tolerance grades in metric and English dimensions for master, setting, or working applications.

"Go" spline ring gage

There are three main types of ring gauges: go, no go, and master or setting ring gauges.

Go ring gauges provide a precision tool for production comparative gauging based on a fixed limit. Go gauges consist of a fixed limit gauge with a gauging limit based on the plus or minus tolerances of the inspected part. A go ring gauge's dimensions are based on the maximum OD tolerance of the round bar or part being gauged. A go plug gauge's dimensions are based on the minimum ID tolerance of the hole or part being gauged. The go plug (ID) gauge should be specified to a plus gauge makers' tolerance from the minimum part tolerance. The go ring (OD) gauge should be specified to a minus gauge makers' tolerance from the maximum part tolerance.

No-go or not-go gauges provide a precision tool for production comparative gauging based on a fixed limit. No-go gauges consist of a fixed limit gauge with a gauging limit based on the minimum or maximum tolerances of the inspected part. A no-go ring gauge's dimensions are based on the minimum OD tolerance of the round bar or part being gauged. The no go ring (OD) gauge should be specified to a plus gauge makers' tolerance from the minimum part tolerance.

Master and setting ring gauges includes gauge blocks, master or setting discs, and setting rings are types of master gauges used to calibrate or set micrometers, optical comparators, or other gauging systems. Working gauges are used in the shop for dimensional inspection and periodically checked against a master gauge.



Telescopic gauge set

These are a range of gauges that are used to measure a bore's size, by transferring the internal dimension to a remote measuring tool. They are a direct equivalent of inside calipers and require the operator to develop the correct feel to obtain repeatable results.

The gauges are locked by twisting the knurled end of the handles, this action is performed to exert a small amount of friction on the telescopic portions of the gauge (the smaller diameter rods found at the T head of the gauge). Once gently locked to a size slightly larger than the bore, the gauges are inserted at an angle to the bore and slowly brought to align themselves radially, across the hole. This action compresses the two anvils where they remain locked at the bores dimension after being withdrawn. The gauge is then removed and measured with the aid of a micrometer or caliper.



Small hole gauge set. Sizes from top to bottom: 3 to 5 mm (0.118 to 0.197 in) 5 to 7.5 mm (0.197 to 0.295 in) 7.5 to 10 mm (0.295 to 0.394 in) 10 to 13 mm (0.394 to 0.512 in)

Small hole gauges require a slightly different technique to the telescopic gauges, the small hole gauge is initially set smaller than the bore to be measured. It is then inserted into the bore and adjusted by rotating the knurled knob at the base, until light pressure is felt when the gauge is slightly moved in the bore. The gauge is then removed and measured with a caliper or micrometer.


Hardened and ground plug gauge

Replaceable thread and plug gauges


Go-NoGo gauge (or Go/no go) refers to an inspection tool used to check a workpiece against its allowed tolerances. Its name derives from its use: the gauge has two tests; the check involves the workpiece having to pass one test (Go) and fail the other (No Go).

It is an integral part of the quality process that is used in the manufacturing industry to ensure interchangeability of parts between processes, or even between different manufacturers.

A Go NoGo gauge is a measuring tool that does not return a size in the conventional sense, but instead returns a state. The state is either acceptable (the part is within tolerance and may be used) or it is unacceptable (and must be rejected).

They are well suited for use in the production area of the factory as they require little skill or interpretation to use effectively and have few, if any, moving parts to be damaged in the often hostile production environment.