Telescoping ballbar systems

The telescoping ballbar is almost universally accepted as the most practical, convenient and comprehensive tool for assessing the contouring accuracy of CNC machine tools.

Renishaw ballbars have been dominant in this market for nearly 20 years and that leadership continues today with the QC20-W wireless ballbar system.

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This telescoping ballbar provides a simple, rapid check of a CNC machine tool's positioning performance to recognised international standards (e.g. ISO, ASME etc) allowing users to benchmark and track the performance of their machines and to quickly diagnose problems that may require maintenance and the error sources that produce them.  

 Regular ballbar testing of machine tools helps to 

  • ensure accurate parts, first time, from CNC machines
  • reduce machine down-time, scrap and inspection costs
  • demonstrate compliance with machine performance and quality management standards
  • implement fact based predictive maintenance


QC20-W system System software Why use a ballbar? QC20-W testing Laser and ballbar support
QC20-W and centre pivot Ballbar 20 software Quality control failed component QC20-W ballbar and plot Support 
Everything you need in a handy case. Just add a PC and go! Powerful analysis  pinpoints errors automatically What can a QC20-W ballbar do for you? Simple and quick to set up and run 

FAQs, downloads and support articles 

What is a Renishaw ballbar?

QC20-W ballbarThe Renishaw QC20-W ballbar system consists of the ballbar itself (essentially a very high accuracy, telescoping linear sensor with precision balls at each end) and precision magnetic mounts, one (adjustable) attached to the machine table and the other to the machine spindle or spindle housing. In use the balls of the sensor are kinematically located in the magnetic cups. This arrangement enables the ballbar to measure minute variations in radius as the machine follows a programmed circular path around the mount on the machine table.

The data collected is sent to a PC, where Renishaw's software calculates overall measures of positioning accuracy (circularity, circular deviation) in accordance with international standards such as ISO 230-4 and ASME B5.54 or in Renishaw’s own analysis reports. This report uses a unique mathematical analysis to diagnose many additional individual machine errors from the set of linear readings. Data is displayed graphically as well as in numeric format to aid and support diagnosis.

Ballbar history

The ballbar came to prominence following the work of James B. Bryan at Lawrence Livermore National Laboratory in the USA, who received a US patent for a 'Telescoping Magnetic Ball Bar Test Gage' in 1984. Renishaw plc launched their first ballbar, the QC10 Mk1 in 1991, to be followed the next year by the QC10 Mk2; using a serial interface rather than the internal PC board of the Mk1. 

The QC10 continued in manufacture until October 2009 when it was superseded by the QC20-W system. The new QC20-W system is based around a completely new Renishaw designed sensor, Bluetooth® wireless technology and substantially updated testing and analysis capability. Renishaw ballbars have been adopted by many thousands of machine tool users worldwide and are considered vital equipment by most leading machine tool OEMs and their distributors as well as many independent calibration service providers and end users.


Related products - Machine Checking Gauge (MCG)


Renishaw's Machine checking gauge (MCG) provides an easy way to monitor the volumetric measurement performance of your co-ordinate measuring machine (CMM). The results give assurance that measurements taken on the CMM are accurate, or give conclusive proof that servicing or re-calibration work is needed. The process is quick and cost effective and a range of pillar heights and arm lengths mean that volumetric accuracy can be checked on both large and small CMMs.

The MCG is an effective complement to existing standards for CMM verification and can be used as an interim checking gauge in accordance with international standards BS EN ISO 10360-2.

Next steps

Contact us online if you require more information or you have a pricing query, or alternatively you may like to speak directly to your local Renishaw office.