Categories: Shaft Alignment

A Leg to Stand On?

| |

By on March 30, 2012

A VibrAlign trainer recently conducted a shaft alignment training class on the Fixturlaser XA Pro. This 1 ½ day class includes one day of classroom training, followed by a half day of field training, usually on the customer’s own in-plant machinery, using their new shaft alignment tool.

While conducting the classroom portion of the training, one of the maintenance managers commented, “We’ve got a pump we’d like for you to help us align. It was recently installed, but it hasn’t been aligned.”

The machine is a 75hp motor, driving a centrifugal pump. A brief inspection of the pump revealed one other problem – one that could shorten the life of the machine as much as misalignment.

Do you see it? How could this affect the effectiveness of the alignment? What would you do different?

About the Author

Stan Riddle joined VibrAlign in 2008. He has over 35 years experience in aligning industrial machinery. Stan received his AAS Degree in Machinist Technology from Surry Community College in Dobson, NC, and also holds a diploma in Industrial Systems Technology from Forsyth Technical Community College in Winston-Salem, NC, where he was also an instructor in the program.

Stan began his maintenance career working as a machinist and millwright for companies such as Weyerhaeuser, R.J. Reynolds, and Tyco Electronics. He also has over 25 years experience in Predictive Technologies, such as vibration analysis, thermography, oil analysis, and ultrasonic inspection. He is a certified Level III Vibration Analyst with the Vibration Institute, and is a Past Chairman and Board Member of the Piedmont Chapter.

Stan and his wife live in Yadkinville, NC.

6 responses to “A Leg to Stand On?”

  1. Michael Keohane says:


    Are all corners of the base mounted on threaded rod like that? If so I would anticipate having other problems such as resonance show up. Also it would seem like it would be almost impossible to have a flat mounting system with everything tight.

  2. Stan Riddle says:

    Yes, all corners are like that. They used heavy gauge steel for the structure, but the threaded rod is not sufficient to support the weight of the machine, piping, and the dynamic forces from operation. You are correct about both resonance issues, and the difficulty of alignment. Good eye!

  3. Jack McLemore says:

    For my info why would they ever mount anything like that?

  4. Stan Riddle says:

    Great question Jack! I wish I had an equally good answer. I can only assume either no one knew better, they hoped the base would last longer, since it wouldn’t be touching the floor, or it was just easier to hook to existing piping. It’s not the first one I’ve seen, and sadly, may not be the last.

  5. Mike Franzen says:


    It looks like to me they tried to make it fit the piping instead of installing and plumbing to it. This is a unstable base with lot of vibration issues. Even if you get it aligned it will never hold one. It should have been mounted on floor and solidly mounted and had a base poured around it. I believe three times more mass than the pump and motor so it could dampen the vibration.


  6. Stan Riddle says:

    Mike, you are exactly right, I believe. They ran the pump to the pipe, istead of running the pipe to the pump. I learned the 3:1 rule of thumb too, but you don’t see as much of it anymore. For many machines, it’s more like 1:3. A base of threaded rod like this one will twist like Chubby Checker!