(Click here to view the 10 year history of the various challenges):

Call for Participation: Spindle Metrology Challenge.

The ASPE Student Challenge committee is excited to announce this year’s challenge: Measuring spindle error motion of a precision air bearing. The Student Challenge will be held as part of the ASPE annual conference in Houston, Texas, November 4-8. Student teams from the United States and international universities will participate. A network of professionals from ASPE will support the teams both during preparation, and the competition.

Spindle error metrology is selected as this year’s challenge due to its importance in modern manufacturing technologies. Student teams will explore the principles and techniques to measure spindle error using Donaldson ‘reversal’ technique. In spindle metrology, the idea of reversing a calibration artifact to separate its error from system errors was first demonstrated by ASPE 1995 Lifetime Achievement Award recipient Bob Donaldson. Using reversal, measurement errors can be reduced below the level of the calibration artifact.

For this purpose, student teams will use; a Professional Instruments 3R Air Bearing Spindle with radial error of less than 25 nanometers, a high-resolution Lion Precision capacitance probe, and a precision ball as a rotating target as illustrated below. The primary goal is to demonstrate how the reversal method decouples the measurement artifact errors from the spindle errors and evaluate the factors that prevent the uncertainty of these measurements from approaching the limits of the measuring probe. This will be followed by decoupling the asynchronous errors of the spindle and measurement sphere- see possible method illustrated in figure 1.

Spindle metrology is integral to ensuring the quality and performance of instruments and machines affecting various aspects of modern life and impacting industries such as transportation, energy generation, healthcare, security, electronics, nanomaterials fabrication, aerospace, optics manufacturing, metrology, and more. The Donaldson Reversal principle offers a reliable and efficient method for spindle metrology, providing engineers with valuable insights into spindle performance and aiding in the enhancement of manufacturing precision.

Figure 1. Source: Dr. Eric R. Marsh, “Precision Spindle Metrology”, 2008 

Prelim Rubric (More details to follow soon):

• Understanding of the Donaldson Reversal Principle: Explanation of the principle’s application in spindle characterization (10 points).

• Accuracy (50 points): Your spindle will be measured at the competition using the setup from the Professional Instruments company, and you will be graded based on the proximity of your measurements to those obtained by the professional setup.

• Presentation and report (40 points): Clarity and organization of the presentation, ability to effectively communicate findings.

Prelim Calendar:

4/26/2024: Student Teams registration is now open. Registration will be closed as soon as we reach 8 teams.


For questions or comments please email us at

Last Edited: April, 28 2024