A few months ago, while teaching a shaft alignment training class, a customer asked if we could take a look at a machine that the maintenance group was having trouble assembling.

Backward HubAfter a quick inspection, the photo on the right was taken. Do you notice anything unusual? Leave a comment below if you spot it.

Don’t laugh! If you’ve been in maintenance for very long, you’ve probably done the same thing–or worse!

Sometimes, when performing troubleshooting as a part of shaft alignment, we miss some obvious clues. Things such as:

  • Shims stacks that are loose. A good sign of soft foot, a loose bolt or both.
  • Obvious coupling wear, such as that pile of bright orange dust underneath a bright orange coupling. There is really no good reason to align a worn coupling insert–replace it first.
  • Loose coupling hubs. Look for loose bolts, missing keys or an undercut shaft diameter.
  • Loose bolts in the baseplate or frame. This can be a cause of vibration, alignment discrepancies, wear, etc.
  • Pipe hangers, saddles, or stiff legs that aren’t supporting the weight of the piping.
  • Too much, or too little lubrication.
  • And yes, assembly errors.

VibrAlign sells some excellent alignment tools, but the two best alignment tools are your eyes and your brain. And the one quality that separates a mediocre “aligner” from an excellent “aligner” is the ability to troubleshoot.

Don’t forget the obvious.

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  1. jgentleman on September 17, 2011 at 10:04 am

    Just testing this to see what happens.

  2. Patrick Lawrence on September 17, 2011 at 10:32 am

    Hey, Joel. Since it’s moderated, I get a notification of your reply and then approve it. Cuts down on spam.

    Did you spot what was wrong?

  3. jimmie rodrigue on September 19, 2011 at 9:34 am

    Coupling installed incorrectly

  4. Patrick Lawrence on September 19, 2011 at 9:46 am


  5. Alan Towers on May 28, 2012 at 2:31 pm

    This is the kind of “gotcha” that happens to everyone eventually.

    Just because the pieces seem to fit together doesn’t mean they’re assembled correctly!

  6. Stan Riddle on May 28, 2012 at 3:49 pm

    You’re right Alan! There’s nothing quite so disappointing as completing an alignment, only to look over and see you forgot to put the retaining ring on! I admit, I’m guilty!

  7. Ramakrishna on September 19, 2012 at 10:19 am

    The guy put the Flange on the reverse with the hub towards the counter flange ….

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