Shaft Alignment and Soft Foot Checklist

May 21, 2010

Several points should be checked prior to laser shaft alignment in order to avoid problems later and to achieve good results:

  • Foundation: A solid, rigid foundation is essential for a successful alignment.
  • Machine Mobility: It is advisable to set both machines with about 80 mils of shims underneath the feet in case one machine needs to be lowered. Also, jacking bolts provide a safer and more accurate way to make horizontal moves.
  • Rigid Couplings: Must be loosened to achieve accurate readings.
  • Coupling Play: This can be avoided by turning the shafts a few degrees before starting measurements and then taking readings in the same direction.
  • Bearing Play: Check for excessive bearing play.
  • Soft Foot: Check for and correct soft foot before performing final alignment.

Watch our Webinar: Laser Shaft Alignment: Repeatability and Accuracy issues. Troubleshooting your readings.

Soft foot can severely affect the operating condition of a machine, and will undoubtedly shorten its life expectancy. Here are a few simple tips to help avoid soft foot in your machines:

  • Eliminate rust, dirt and any other contamination from the contact surfaces of the machine feet, shims or foundation.
  • Avoid using more than four shims at a time under the machine foot. More than three shims can cause a spring effect.
  • Eliminate undue external forces on the machine frame such as those from connected piping, conduit, auxiliary supports, etc.
  • Use high quality, clean and uniform shims when shimming is necessary.

Watch  our Webinar: Soft Foot

2 Responses to “Shaft Alignment and Soft Foot Checklist”

  1. A soft foot needs to always be checked when completing an alignment. There have been times that technicians are “chasing their tails” and spending unnecessary time and efforts during the alignment. In my experience, checking for a soft foot first provides additional information regarding the base or mounts to ensure that the machine is on a level plane. This has saved many hours of me being in the field and ensuring that my alignment is effective.

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