Achieving a perfect alignment can seem daunting at times, but it doesn’t have to be if you have the right tools and if you know to look out for three common reasons for shaft alignment frustrations. Once you know these three factors, you can take the necessary steps to avoid them and/or correct them.

The first most common reason for shaft alignment frustration is looseness of some kind. This could be looseness in:

  • Couplings
  • Bolts
  • Sensors
  • Chain or magnetic brackets
  • Motor feet

This is not an exhaustive list but is a good place to start. For a more thorough list of things to check, see a companion VibrAlign blog article titled “Troubleshooting Looseness during Shaft Alignment.”

The next common reason for shaft alignment frustration is failing to address backlash.

According to a previous VibrAlign blog post titled “Coupling Backlash—How it Affects Alignment, and How to Minimize It”:

“Simply stated, backlash is angular movement in any mechanical system between mating parts. Coupling backlash is common, and to a point, desirable in many types of couplings. However, the amount of coupling backlash required for efficient coupling backlash is minimal. Often, excessive coupling backlash is caused by a worn coupling insert.”

Causes of backlash can include but are not limited to:

  • Worn coupling insert
  • Improper hub to shaft fit
  • Loose foot bolts

Be sure that you make it a priority to replace machine parts that are suffering from excessive wear in order to prevent backlash issues.

The last issue which is a common cause of shaft alignment frustration is soft foot.

According to the VibrAlign blog post “Soft Foot—What it is and How to Minimize it”:

“Soft foot is a common issue when aligning rotating equipment. It is a major cause of repeatability problems in shaft alignment measurements. In addition to alignment quality and repeatability problems, it can be a cause of machinery vibration, reduce life in electric motors, and cause internal clearance problems in gearboxes and pumps.

But if the proper precautions are taken, soft foot can be minimized and controlled.”

To read more on how to eliminate soft foot, click here or watch the video below.



So now you know the top three reasons why you may be experiencing alignment frustrations despite seemingly taking the necessary steps to align your machine correctly. We recommend methodically going through these three steps to check for looseness, backlash, and soft foot, and then be sure to check out for other helpful posts on how to address each of these issues.


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