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Types of styli

The comprehensive range of genuine Renishaw styli comprises a range of configurations to suit different measurement applications.

Straight styli

Naming protocol:

M2 STY D2R L20 EWL14 D1.4SS


M2 thread straight stylus with a ø2 mm ruby ball, 20 mm in length, effective working length of 14 mm and a stainless steel ø1.4 mm stem.

The simplest and most frequently used type of stylus, these are suitable for the majority of probing applications. Styli can have balls made from ruby, silicon nitride, zirconia, ceramic or tungsten carbide. The holders and stems come in a range of materials - titanium, tungsten carbide, stainless steel, ceramic, carbon fibre.

Star styli

Naming protocol:

M2 STR D2R 5BALL L19.5 S32


M2 thread star stylus with a ø2 mm ruby ball. It has 5 balls on the star and has an overall length of 19.5 mm (from the centre of the ball to the rear of the star mounting face). The span of the star cluster is 32 mm.

These are multi-tip stylus configurations with fixed mounted styli. These can be used to inspect a variety of different features, including surfaces and holes with which direct contact can be made.

This configuration gives flexibility, enabling the tip to make contact with features without changing the stylus. You can configure your own star styli using stylus centres to mount up to 5 styli components.

The balls can be made from ruby, silicon nitride or zirconia. Each tip on a star stylus requires datuming in the same manner as a single ball stylus.

Pointer styli

Naming protocol:

M2 PNT D1.4TC 30 DEG L10


M2 thread pointer stylus with a ø1.4 mm tungsten carbide stem/tip. The angle of the tip is 30° and 10 mm in length.

These should not be used for conventional XY probing as they have been designed for the measurement of thread forms, specific points and scribed lines (to lower accuracy).

Using radius end pointer styli allows more accurate datuming and probing of features, and can also be used to inspect the location of very small holes.

Hemispherical styli

Naming protocol:

M5 HEM D30 CER L26.5


M5 thread hemispherical stylus with a ø30 mm ceramic hemisphere. The length is 26.5 mm from the end of the hemisphere to the mounting face.

These are ideal for probing deep features and bores in X, Y and Z directions with the need to datum only one ball.

In addition, the effects of very rough surfaces can be averaged out by probing with such a large diameter ball.

Cylinder styli

  • M2 ruby cyclinder styli

Naming protocol:



M2 thread cylinder with a critical measuring element of ø3 mm made from silver steel. It has an overall length of 13 mm and an effective working length of 4 mm.

These are used for probing holes in sheet metal, pressed components and thin work pieces with which proper contact cannot be guaranteed with ball styli.

In addition, various threaded features can be probed and the centres of tapped holes located.

Ball ended cylinder styli allow full datuming and proving in X, Y and Z directions thus allowing surface inspections to be carried out.

Disc styli

Naming protocol:

M2 DSC D18 SLVS T2.2 L2.6 BR-Y


M2 thread disc stylus with a disc diameter of 18 mm. It is made from silver steel with a disc thickness of 2.2 mm and a length of 2.6 mm. BR stands for balls/rollers followed by yes (Y) or no (N).

These styli are sections of highly spherical balls used to probe undercuts and grooves within bores, which may be inaccessible to star styli. Although probing with the spherical edge of a simple disc is effectively the same as probing on or about the equator of a large stylus ball, only a small area of this ball surface is available for contact. Hence thinner discs require careful angular alignment to ensure correct contact of the disc surface with the feature being probed.

A simple disc requires datuming on only one diameter (usually in a ring gauge) but limits effective probing to only X and Y directions. Adding a radius end roller allows you to datum and hence probe in the Z direction, providing the centre of the 'radius end roller' extends beyond the diameter of the probe. The radius end roller can be datumed on a sphere or a slip gauge. Rotating and locking the disc about its centre axis allows the 'radius end roller' to be positioned to suit the application.

Disc may also have an M2 threaded centre to allow the fixing of a centre stylus, giving the additional flexibility of probing the bottom of deep bores (where access for the disc may be limited). These styli are available in various diameters and thicknesses and can be made from steel, ceramic or ruby.


Naming protocol:

M4 EXT L15 D7 SS


M4 thread extension with 15 mm length, ø7 mm, made from stainless steel.

These are available in different lengths and materials – steel, titanium, aluminium, ceramic and carbon fibre.

With long extensions consideration must be given to the thermal characteristics of the material.

Tool datuming styli

Naming protocol:

Tool datuming styli vary significantly but tend to have a common mounting M4 thread or ø4 mm hole.

On 4-sided square tips, the length (L) is from the measuring face to the mounting face. For 5-sided cubes and round discs the length is to the front face.

The tolerances to which tools can be set depends upon the flatness and parallelism of the stylus tip to the machine axis.

Fine adjustment is provided on all probes and probe holders to allow these settings to be achieved.

Where rotating tools are to be datumed for diameter the tools must be rotated in reverse to the cutting direction.

Crash protection

Renishaw's stylus crash protection devices are designed to break in the event of impact and protect the probe from damage.

Custom styli

Renishaw offer a comprehensive custom styli service, designing and manufacturing a specific stylus to suit your requirements.

Our in-house teams have a wealth of experience and expertise, considering probe and application needs to ensure the best solution is found.

Visit the custom styli page to find out more.


Styli applications gallery