Tom M. a maintenance supervisor at GSO &M sent us the above question. Some of our original response to the question above was incorrect. We recently received an email from a reader who pointed out our error. It is our desire to publish correct and accurate information. So please accept our apology and note the [...]

Axial Preload for Angular Contact Bearings Preload is the load generated from the axial or radial interference within a bearing resulting in elastic deformation between rolling elements and the raceway. In other words, preload is the amount of force exerted against the rolling elements without the application of any external forces. Proper preload [...]

HST only uses top name brand ABEC 7 bearings ABEC ratings have to do with the quality and precision of the bearing. It is an industry accepted standard developed by the Annular Bearing Engineering Committee (ABEC) of the American Bearing Manufacturers Association (ABMA). There are five (5) ABEC classifications 1, 3, 5, 7, [...]

ISO 1940/1 is an international standard used for qualifying the balance of rotating rigid bodies. The standard also specifies the method for verifying residual imbalance. G0.4 is a particular balance grade within the overall standard. Compliance with this standard requires that the maximum residual imbalance falls within certain limits dependent on the overall mass of [...]

Trim balance is the final balance procedure done to a spindle after assembly and during full speed testing. This is procedure is necessary for two reasons. One, often additional components are attached to the shaft after assembly into the housing. Their imbalance will not be compensated for by the adjustments made on the Balancing Machine. [...]

Imbalance is caused by the displacement of the center of mass from the rotational axis which is a function of eccentricity in the distribution of the rotating mass. It is measured in units of mass and distance, e.g., gram-millimeters or gmm. Imbalance is considered in single plane modes and dual plane modes. Balancing is the [...]

Jessica is applying precision metered ultra-filtered grease in our special flow bench mini-clean room. Today there are many excellent lubricants for the full spectrum of spindle applications. The OEM should always be the first source for lubrication requirements. However, if that information is not available HST makes the following recommendations. Grease: Most spindles [...]

In our data base of over 100,000 repairs we have seen a broad spectrum of failures. Some common failure causes include: Contamination Mishandling Incorrect Preload Overloaded Lubrication Imbalance Drawbar Mechanism Failures Statistical Bearing Failure For some tips on how to avoid premature failure visit our Blog under “ Spindle Tips”. Contamination Minute particulate resulted [...]

A kiss grind, also sometimes referred to as a “breeze grind” is a light surface grind that will remove minor surface damage. It is typically used on tool interface surfaces such as CAT or BT tapers. Because it is a grinding process it can only remove high spots. Often taper surfaces have high spots as [...]

GPG is the abbreviation for Grind – Plate – Grind. This is our process for surface restoration and it is used to restore out of tolerance critical surfaces like bearing journals to original specification.  This process is also used for restoring tool interface surfaces like CAT or HSK tapers. Our experience shows that about 35% [...]