I was invited by Tom Astrene of TLT to write a response to the July 2010 TLT article (Ref. 1). My rebuttal — “In Search of a Fatigue Limit: A Critique of ISO Standard 281:2007” — was published in Tribology and Lubrication Engineering, TLT, August 2010 edition (Ref. 10). While this article is also available online, I will attempt to summarize the essence of my response.

Equipment downtime and reduced component life are a few of the consequences — and potential costs — of using the wrong seals on many types of industrial equipment including pump bearing frames, electric motors, fans, pillow blocks, gearboxes and more. However, if correctly specified and installed, seals provide effective barriers that both retain lubricants as well as protect against water, corrosion, debris and other contaminants.

A nose-in-the-tent peek at the booths featuring mechanical motion components.

conveying system on the varnishing line for a manufacturer of high-end kitchen cabinets were leaking. Oil was dripping on the cabinet parts — ruining the finish. Why were half of the gearboxes leaking?

Without the sun, there would be no Earth and no life. However, our knowledge about our home star is still very limited. This is about to change. In 2018, the European Space Agency (ESA) will send its Solar Orbiter into space, equipped with a thick heat shield.

U.S. manufacturers, such as food processors, face an unprecedented competitive environment and must look for ways to be profitable without negatively affecting the quality of finished products.

I’m building a custom gearbox with 7075 T-6 spur gears, and I’m concerned that aluminum flakes will enter the races on the roller bearings (SKF 2307) and cause premature failure. So my question is — should I place an oil seal on the shaft first to protect the bearing — or is this an unfounded concern and I should mount the seal in the typical manner outside the bearing? Or both? Or go with a sealed bearing? I’m confused and could use your expertise, please.

The improvement of the energy efficiency of industrial gear motors and gearboxes is a common problem for many gear unit manufacturers and end-users. As is typical of other mechanical components, the radial lip seals used in such units generate friction and heat, thus contributing to energy losses of mechanical systems. There exist today simulation tools that are already helping improve the efficiency of mechanical systems — but accurate models for seal frictional losses need to be developed. In this paper SKF presents an engineering model for radial lip seal friction based on a physical approach.

Engineers typically learn that the bearing L10 life can be estimated using the so called “C/P method” — or the “basic rating life” of the bearing, a method rooted in the 1940s. Major developments have since led to the “modified rating life,” released in ISO 281:2007, which includes the aiso life modification factor. In this paper a succession of equations used for bearing life ratings are reviewed, and current bearing life rating practices are discussed in detail. It is shown that — despite the introduction more than 30 years ago of the adjustment factor of the basic rating life, and the standardization in 2007 of the aiso modification factor — use of these improved calculation methods are not practiced by all engineers. Indeed — many continue referring to the old model as a way of seeking compliance with existing, established practices.

For either brand-new motors or those already in service, "best practices" means that informed technicians can make use of the latest diagnostic techniques (vibration analysis, thermography, shaft-voltage testing, etc.) to prevent electrical bearing damage -- either at the very beginning or very quickly thereafter. If done correctly, the work need only be done once.