Categories: Shaft Alignment

Why do people struggle with alignment? Part 1

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By on March 6, 2014

After a shaft alignment check, if it’s out of tolerance, some maintenance personnel will skip the pre-alignment checks and proceed directly to correcting the vertical and horizontal misalignment. Frustration begins to set in as the alignment results go back and forth and seem inconsistent. The laser shaft alignment instrument says to add 20 mils to the front feet and 50 mils to the rear feet.  So they do. The hold down bolts get tightened. The new alignment results are again confusing, as now they show to remove shims and the frustration level gets higher!

Sound familiar?  What should you do?

Stop, take a breath, back-up and take a look at the big picture. First and foremost, when reusing the existing shims you need to evaluate those shims and make a note of the total amount of shims under each foot of the movable machine.

We advise our clients to clean under the motor feet and consolidate shim piles with no more than 5 shims under a given foot. While that may seem like a waste of time, it will actually speed up the alignment process.  Knowledgeable aligners who do this regularly and mic each shim pile, consolidate and replace it with clean, new shims.   And that is a good thing!  But that’s only half of the picture.

shim stack

We think it is also important to know and document the total shim count under each foot.  This is the shim count we found during a recent training session under the feet of a 25 HP motor. Can you imagine the problems that would occur if the shims were replaced individually without comparing and seeing the big picture?

What would you do in this situation?

2 intial shim count

Check back for part 2 of the story.

About the Author

James Pekarek joined VibrAlign in 2013. He has 18 years of experience in machine installation, electrical systems, maintenance and service management.

James began his career in the automation industry installing and maintaining various types of machinery and performing technical training to customers in the semiconductor industry. He spent 3 years with Cummins Industrial Power Generation as Service Manager. James also spent 3 1/2 years as lead Electrical Instructor at a vocational college serving the Wind Industry. While there, he gained his NFPA 70E certification as well as NEC 1910. James is also a certified Electrical Safety Instructor.

During his technical instruction career, James was introduced to VibrAlign and many of the products. He was impressed by the company philosophy and values and decided to pursue a career as a technical instructor with us.

James and his family live in Vancouver, Washington. He enjoys the outdoors, family time and building cars.

3 responses to “Why do people struggle with alignment? Part 1”

  1. paljoy says:

    Just by looking at the shims you are going to build in a angular soft foot. should only be .007″ from front foot to back foot at a 10″ span between feet with a 1800 rpm motor. Also looks like soft foot was over corrected and shims were added to re correct the problem. I would suggest starting over. If soft foot is that large have motor feet machined flat.

  2. […] my previous blog entry “Why do people struggle with alignment? Part 1”, we discussed the importance of not only micing, cleaning, and consolidating shims but also noting […]

  3. RonO says:

    I would agree that there is a softfoot problem. However, the problem could be with the base, the motor or a combination of both. I would start over focusing on all the preliminary aspects: base, shaft runout, pipe strain, check the motor feet, mechanical looseness, shims, housekeeping, etc. Then I would check softfoot.