Posts tagged with: Alignment tolerances

Just Get It Running, We’ll Fix It Later!

| | | | | |

By on June 13, 2018

  Sound familiar? I can’t tell you how many times I personally have heard this over the years. I am sure many of you have as well. The issue is, scheduled downtime seems to be put on the back burner so to speak, to meet production goals. And as it has become all too familiar, […]

Read More

Are Shims Causing a Soft Foot Issue?

| | | | |

By on May 15, 2018

One of the many things I love about my job is the numerous challenges we face during the field alignment portion of our Precision Shaft Alignment Training. Prior to the training, there were some repeatability issues when attempting to perform a precision alignment on this piece of equipment. One of the main causes of non-repeatability […]

Read More

You Can’t Perform Precision Alignment on Un-precise “Stuff”!

| | | | | | |

By on May 11, 2018

Alan Garbers with Johnson Controls International contacted me regarding an alignment problem, and asked for my advice.  Here is a condensed version of his email. A client rents portable chillers, and related equipment. They built a 125HP portable pump skid with a Bell & Gossett pump on a VFD. I was there to commission the […]

Read More

Understanding Spacer Shaft Alignment

| | | | | |

By on April 25, 2018

The majority of precision shaft alignments are relatively close coupled where there are only a couple of inches between the shaft ends of the driver and driven elements. Close coupled alignment quality is traditionally displayed as angle (driver to driven) and offset (at the center of the coupling). The question is what do you do […]

Read More

Stupid Questions

| | | | |

By on February 8, 2018

While on the road conducting precision shaft alignment training I run across a wide range of skill level. It is not uncommon to have a lot of questions. I like it when there are questions, that is usually an indication that the trainees are engaged. It is also not uncommon that a question starts with, […]

Read More

OEM Specifications

| | | | | | | |

By on September 7, 2017

Whether instructing a training class for precision shaft alignment or geometric measurements, the topic of machine specifications frequently comes up. Specifications such as shaft alignment tolerances, bolt torque values, frame or base flatness requirements and the frequency of verification of these specifications are typical of what is asked. There are general industry specifications such as […]

Read More

Fire Pump Maintenance

| | | |

By on August 30, 2017

Fire Pumps are a critical safety item in facilities across the world. Their purpose is to make sure a building has enough water pressure in case of a fire emergency. Of course, the hope is that they are never needed but if they are they need to perform reliably. Fire Pumps are typically tested on […]

Read More

Pipe Strain Was the Issue

| | | |

By on July 13, 2017

Have you ever struggled with a precision shaft alignment, even though you did everything right? (Preformed the pre-alignment steps, controlled backlash, etc., etc.) So, what was different? Maybe it was pipe strain. An alignment check of a new installation of a 40 HP, 3600 RPM motor/pump  revealed the vertical angular misalignment was 3.2 times the […]

Read More

Is there such a thing as “Too Good” of a Precision Shaft Alignment?

| |

By on April 6, 2017

This question comes up frequently in our Shaft Alignment Best Practices training classes. The result screens below both show two different aligned machines meeting 3600 tolerances.   The question is; is one better than the other? There has been a lot of discussion about this very topic. The theories are abundant and points of view […]

Read More

Coupling Tolerances vs. Shaft Alignment Tolerances, What’s The Difference?

| | | |

By on June 24, 2016

Plenty! This question still comes up fairly often in our training classes. If you look any of the coupling manufactures installation instructions there is a chart for the maximum allowable misalignment based on the coupling size. These tolerances are for the coupling, what about the machines the coupling connects? Shaft alignment tolerances are more about […]

Read More

Repeatability vs. Desired Outcome in Shaft Alignment, Part 2

| | | |

By on December 2, 2015

In my last post, we looked some reasons for non repeatable, or when “two plus two doesn’t equal four”. This time, let’s think about when we don’t get an expected or desired outcome when we shim and move. Think of it as when “two minus two doesn’t equal zero.” You may perform an alignment measurement, […]

Read More

Repeatability vs. Desired Outcome in Precision Shaft Alignment, Part 1

| | | |

By on October 14, 2015

When mechanics align rotating machinery, they expect two outcomes. One, they expect their alignment values to be repeatable. Two, they expect shimming and moving machinery to produce a desired outcome-namely, to be in tolerance. In this paper, we’ll discuss repeatability, which is, performing the same measurement twice, and getting the same results. If alignment results […]

Read More

Don’t Overlook the Hold Down Bolt Washers

| | | |

By on January 22, 2015

Anyone involved in precision shaft alignment knows that unintentional movement is the biggest contributor to non-repeatable alignment results. Movement can come from several sources: Soft foot, loose bolts, flexible bases, excessive bearing clearances, improperly mounted or loose sensor mounting hardware, etc. One of the more elusive and least considered sources of movement is cupped washers […]

Read More

Uncoupled Shaft Alignment – It Doesn’t Need To Be Difficult.

| | | | |

By on October 13, 2014

The night before the OJT portion of a recent Fixturlaser GO Pro Training class, at a Combined Cycle Power Plant, the shim packs of the disc type coupling between a 3300 HP electric motor and fluid drive began to fail. The machine was shut down before any damage could occur and was waiting for our […]

Read More

Coupling Alignment Tolerances vs. Shaft Alignment Tolerances

| | | |

By on October 8, 2014

A coupling alignment tolerance and a shaft alignment tolerance are different things – VERY different things! A Coupling Alignment Tolerance is often (but not always) the maximum amount of misalignment the coupling will operate at before premature failure. A Shaft Alignment Tolerance is the maximum amount of misalignment the shafts can tolerate before they begin […]

Read More