How to Deal With Thermal Growth

Machine Train
All rotating machinery is subjected to thermal exposure. The machines will react differently depending on temperature and material, either by expanding or shrinking. And that is a fact. Thermal growth is a serious thing when you think about it.

All rotating machinery is installed in trains. Trains mean there is a driver, the motor, and driven, which can be a pump, blower, compressor, or any other type of process machine. During the installation of rotating machinery, precision shaft alignment is performed. The shaft alignment will ensure that both shafts (driver and driven) are collinear. Collinear means that both rotational centerlines are positioned as if they were one.

The effect of heat on driver vs. driven

When the machines are started, the driver and driven heat up in very different ways. A compressor in a hot environment will quickly increase in temperature due to friction of its internal rotating parts, and compression of the media will generate and add more heat. Comparing to the driver, which can be an electrical motor, the situation is very different. The temperature will increase to a certain level and then remain the same — two machines with two different behaviors.

So, what happens when one of them increases its temperature relative to the other? It’s simple; the machine will start expanding. And when the machine expands, it will grow in all directions, move its rotational center out of collinearity and cause misalignment. But not only misalignment. Since there is a change in the machine geometry, pipe strain might also add more stress to the housing.

Machines Expand Differently

Take thermal growth into account from the start

There are so many consequences of thermal growth in rotating equipment. Misalignment will, for example, also result in a bent shaft. Bent shaft will result in improper distribution of forces in the bearing, which will lead to failure of the lubrication. Therefore, we must be able to anticipate thermal growth by using available information from the OEM, or by performing the calculation by ourselves. So how do we do that?

The key is to identify how much growth to expect. This number must be used when performing the shaft alignment to “intentionally misalign” the machines prior to start. Let us use the compressor as an example again. If we assume that the compressor will operate at a higher temperature than the motor, when aligning, we must place the compressor below the rotational centerline of the motor. How much below will be determined by the expected thermal expansion growth of the material.

Thermal Expansion by Material

Final test run

When the machine is aligned with the thermal growth considered, it must run and operate until it reaches its full operating condition. Then it must be stopped, and the shaft alignment verified. This is our test run of the machine, to confirm a proper and reliable installation, and to achieve full operational life. We want to test before we go to full production to ensure our thermal expansion calculation was correct.

Think about aircraft maintenance. When there is an aircraft engine replacement, the pilots perform test flights until it can be confirmed that everything is operating as it should. And you don’t want to be on the plane knowing nobody performed the test run, do you?

Watch our Shaft Alignment Know-How: Thermal Growth video to learn the importance of accounting for thermal growth on rotating equipment.

Thank you Roman Megela with Easy-Laser for sharing this informative article with us!

Thermal Growth in Alignment Components: Achieve Reliable Results With These 4 Tips

by Diana Pereda

In industrial facilities, the efficient operation of condensate pumps is crucial for maintaining production processes and avoiding costly downtime. Proper alignment is a crucial aspect in maintaining the performance of these pumps, with vertical alignment playing a critical role.

When aligning a vertical condensate pump, there are several key considerations to keep in mind. Here are a few:

  • Shaft Alignment: The alignment of the pump and motor shafts is crucial for ensuring smooth operation and preventing excessive wear and tear on the components. Any misalignment can lead to increased vibration and potentially cause premature pump or motor failure.
  • Base Plate Flatness: The base plate on which the pump is mounted must be level and flat to provide a stable foundation for the pump. A distorted or uneven base plate can cause misalignment and compromise the performance of the pump.
  • Pump Shaft Bearings: Condensate pumps are typically assembled and bored in one operation to ensure bearing alignment. The pump components should be marked and pinned prior to bearing and pump shaft inspection to prevent misalignment during reassembling as the components may not be properly indexed to each other.
  • Coupling Consideration: A condensate pump usually has a rigid type of coupling that supports the pump shaft. The coupling must be disengaged and the pump shaft should be centered to the bearing housing. The shaft alignment should then be checked between the static pump shaft and the rotatable motor shaft.  If the coupling is flexible (such as a gear-type coupling as shown below), the measurement can continue using alignment methods that involve rotating both shafts.
Vertical Machine Alignment
Courtesy of Brian Franks with Jettech Mechanical

By considering these best practices, you can ensure the optimal performance and longevity of your vertical condensate pump. Regular maintenance and alignment checks can also help maintain performance and prevent costly downtime.

Laser Alignment for a Vertical Water Pump with Easy-Laser XT

by Diana Pereda

It’s time to talk about torque! This topic is one of the most neglected aspects of Machine Maintenance. Equipment is designed to perform tasks reliably and efficiently. This can be accomplished if the machine is used as intended, and maintenance performed according to the specifications established by the manufacturer of the machine. There are always adjustments needed to accommodate local conditions, but those adjustments rarely mean making changes to specifications such as torque. If that specification is not adhered to, performance and reliability can suffer.

First, let us talk about what torque is. In a normal situation, the rotational force is applied to turning a fastener to achieve a specific clamping force. We are turning the nut or bolt until the resistance to that turning action reaches a certain point. After that point, we are stretching that joint into what is called the “elastic” working load range for that fastener. If this has been done correctly, the fastener should return to its pre-stretched length if the force is removed. In a case where that stretch does not go away, we have trespassed into the “plasticized” range for that fastener, and it can no longer create the clamping force needed for that joint. If you have ever felt a bolt have a lot of resistance to being turned, then all of a sudden it becomes easier to turn, you just went into that “plasticized” zone (provided you have not stripped the threads), and the bolt is now being stretched beyond its design parameters.

Fastener Thread

A common way to protect the integrity of a clamped joint is to simply use a longer fastener. The normal equation for grip length is to have 12 times the diameter of the fastener in length, to allow for the correct stretch but comfortably work within the “elastic” working range. (By the way, another minimum parameter to look out for is that at least three (but preferably five) threads engage in the joint.

Now that we have established that we need to achieve a correct clamping force, stayed tuned for Part 2 where I discuss how to get there!

Precision Maintenance: The Torque Wrench. Check Out These 15 Helpful Tips!

by Diana Pereda

XT770 Shaft Alignment system in use on a pump-motor set

Well-lubricated and properly aligned machinery are integral to the smooth running and continual functioning of your equipment and overall facility. Shaft alignment of rotating equipment is particularly important, as the unnecessary stress produced by misalignment will cause unexpected and costly downtime.

Poor vertical and horizontal pump alignment damages your equipment’s seals and couplings, which have been proven to cause lubricant leakages and consumption problems. Although you may think replacing the seals is a more affordable fix, seal failure, and lubricant loss is inevitable without addressing the cause.

Before we delve into vertical and horizontal pump shaft misalignment, let’s take a look at the problems caused by misalignment:

  • Increased vibration and noise
  • Premature coupling, shaft, and foundation bolt failure
  • Excessive and costly seal lubricant leakage
  • Premature failure of bearings and seals caused by excessive wear
  • Increased friction which causes excessive wear, energy consumption, and possible premature equipment failure

To prevent these issues and make sure your equipment is running at peak efficiency, it is recommended the pump shafts need to be aligned in horizontal and vertical planes using laser shaft alignment equipment. When these shafts are misaligned, it can be due to parallel or angular misalignment – or likely a combination of both.

Parallel Misalignment

Parallel misalignment occurs when both shafts’ centerlines are parallel to one another in an offset way. It can be divided into poor vertical and horizontal pump shaft alignment.

Parallel Horizontal Pump Shaft Misalignment: In this case, your pump shafts are misaligned in the horizontal plane. The motor shaft has moved away from the pump shaft horizontally. However, both shafts are still operating in the same horizontal plane and are parallel.

Parallel Vertical Pump Shaft Misalignment: This refers to shaft misalignment in the vertical plane. Similarly, this means that the motor shaft has moved vertically away from the pump shaft, with both shafts operating parallel and on the vertical plane.

Angular Misalignment

Angular misalignment can also be divided into poor vertical and horizontal pump shaft alignment. This is when the motor shaft is at an angle with the pump shaft.

Angular Horizontal Pump Shaft Misalignment: Here, the motor shaft is operating at an angle to the pump shaft while operating in the same horizontal plane.

Angular Vertical Pump Shaft Misalignment: Again, your motor shaft and pump shaft are at an angle to one another and operating in the vertical plane.

Download our 5-Step Shaft Alignment Procedure a simple and effective procedure for shaft alignment of rotating equipment.

Thank you John Lambert with Benchmark PDM for sharing this blog with us!

Common Causes of Machine Failure: #1 Misalignment

by Diana Pereda

Cleaning under machine feet

Before going on a trip, we typically plan ahead, what we’re doing and where we are going each day on the trip, and we pack accordingly. When starting an alignment job, it is not that different. Whether it means thoroughly cleaning the mounting base, having the right tools for the job, or allocating the right amount of hours, preparation can go a long way. Cleaning underneath the feet of the machinery will greatly decrease the chances of having a soft foot, thus increasing the machine’s ability to respond accurately to corrections. Also, check under the entire machine for loose debris. This might cause a soft foot as the machine comes down during alignment corrections, even though the feet of the machine are spotless.

Another thing that should be considered during pre-alignment, is to have the right set of shims. These must be the right size for your application, corrosion-proof, and made from high-strength material. They should also be free from burrs, bumps, nicks, and dents of any kind. Of course, tagging out/locking out the power of the machinery is the VERY first step before starting the alignment process. Having trained personnel can also cut down the hours it takes to perform the alignment.

Learn more about our precut SS shims.

Pre-Alignment Planning and Execution Steps for Rotating Machinery


by Adam Stredel CRL

Cooling tower motor with measuring unit mounted

Two new hires called into our office for help with an alignment they were doing with a newly bought Easy-Laser XT laser shaft alignment system. Fortunately, our chief engineer was able to remotely guide them through two successful gearbox-motor alignments. There was still an issue: these gentlemen were inexperienced and being tasked with aligning 20 additional similar setups for cooling towers, in peak Texas heat. The first alignment revealed that our motor, Machine To Be Moved (MTBM) was both base- and bolt-bound. The second alignment also found the motor to be both base- and bolt-bound. Every single cooling tower had identical gearboxes and identical motors that sat on identical “frames”. By the third alignment, a clear pattern formed. This was no coincidence, the jackshafts were 110 inches long, with machines that weren’t centered prior to installation. Small amounts of angular misalignment at the gearbox are enough to cause a bolt- and base-bound condition as the offset produced by the angularity is magnified across the long distance of the jackshaft’s length, making the resulting correction to be performed too large at the motor. An angularity of 0.5 mils/inch is enough to cause a 55-mil offset between the machine shafts at a 110″ separation. It is apparent that it doesn’t take much angle to run out of space in the anchor bolt holes at the motor. The motor sat higher than the gearbox while both machines sat angled slightly downwards, looking towards the center between them.

After realizing they were bolt-bound many experienced alignment technicians would elect to use “Chicago” bolts or undercut bolts, which are designed to allow for a little additional freedom of horizontal movement of the machine. Obtaining them likely would waste several hours, even with a machine shop on site. Another approach is to drill bigger holes in the feet. However, our two junior aligners saved on what could have amounted to several days over the course of all 20 alignments by instead performing optimal moves. An “optimal” move is a small adjustment made to the Stationary Machine (the gearbox in this case) that eliminates the need for the large projected corrections at the Motor. It is the smallest feasible move that will accomplish this objective. In these cases, both front feet were brought up, which is easy to do, since adding shims is always easier than removing them if they aren’t there to start with! This saves time and is generally the most efficient approach to the base-bound situation. In this case, the gearbox was free to move, no piping or another machine coupled to it, so it was a no-brainer. Undercutting bolts is popular because piping and electrical conduit along with other factors make it difficult and, in some cases, impossible to move one of the machines. In any case, an optimal move is worth considering at the very least.  As long as your stationary machine is able to make the SMALL move necessary you will save yourself time. Very little risk considering it, bountiful rewards if it makes sense. It is up to the technician to use their judgement and experience to determine if this is possible and worth the effort.

The third alignment needed two vertical moves to get it within Precision (ANSI/ASA S2.75-2017) Tolerance. The first correction was to shim both gearbox and motor front feet up, this got rid of the base-bound condition at the motor. The second move was to shim all four motor feet up. One horizontal move was necessary via gearbox to get out of bolt-bound condition, no jackbolts on the machine so a hammer was used. Every setup was the same, allowing our junior aligners to employ the template feature of their XT laser system and save more time there as well.

5 Tips for Spacer Shaft Alignments

by Ana Maria Delgado, CRL

Easy-Laser measuring units mounted on shaft

At times, shaft alignment can become extremely frustrating almost as if it is possessed with a mind of its own. One set of readings may indicate that you make adjustments one way, the next set of readings then indicates something completely different. Quite simply, and almost without fail, if there are repeatability issues then something is loose with the laser alignment tool or there is some mechanical play.

Assessing Detector Movement

Here are some simple questions to work through to try and diagnose and address issues with looseness:

  • Are the chain brackets tight to the shaft or hub?
  • Are the detectors tight to the rods?
  • Are the extension rods tight to the brackets?
  • Is the sensor rubbing on something when positioning the shaft?
  • When using magnetic brackets, do the magnets have full contact to prevent them from slipping?
  • Did you bump something out of place?

Assessing Coupling / Bearing Play

Here are some simple questions to work through to try and diagnose and address issues with mechanical looseness or play:

  • Are all the hold-down bolts on all pieces of equipment tight?
  • If it is mounted to a hub instead of the shaft, is the hub tight to the shaft?
  • For sleeve bearings, has the shaft come to rest so you know for sure it’s in the same spot for measuring?
  • Is there coupling play or backlash?
  • Is there any bearing play?
  • For all the above, did you double check and are you sure?

Other Diagnostic Factors to Consider

There may still be base or foot movement that is causing looseness or it could be a torsional movement issue. Simply, you will be able to tell by addressing the operation of the machine to ascertain:

  • If the feet are moving relative to the base
  • If the base is moving relative to the feet
  • If there is debris around the shims and base
  • If multiple shims can be consolidated

Torsional movement addresses looseness in the coupling, whether it is being controlled in a consistent manner if the backlash in the gearing is being controlled, and if the chain or magnetic brackets are fitted tight to the shaft or hub.

Thanks to our colleagues at BENCHMARK PDM for sharing this blog with us!

Laser Shaft Alignment Troubleshooting: Part 1 Repeatability

by Ana Maria Delgado, CRL

machinery installation

Because of my many years of experience in the field of installation and maintenance of rotating equipment, I can say that installation is a fundamental thing. But why is this phase so important?

Well, because the installation has a direct impact on the machinery, and will determine operating conditions, performance, and life cycle cost. Basically, the way you install your rotating equipment is the way it will perform. And personally, I always ask myself why companies buy million-dollar pieces of equipment and let inexperienced installers do the installation. Then, they spend another million dollars on condition monitoring watching them fail.

Don’t get me wrong; condition monitoring is extremely important to understand what is happening to the machines and detect an early failure. But the fact is that most of the failures occur due to poor installation and design. Here, let’s focus on the installation phase of rotating machinery.

What do we expect from our machinery?  

  • Reliable operation – We expect our rotating equipment to deliver its intended purpose or service without failure.
  • High performance – We expect our equipment to perform as per design.
  • Long service life – If our equipment has been designed for 20 or 30 years of operation, that is what we want to achieve.
  • Low maintenance cost – We expect not to spend any additional money after the investment has been made.

Responsibilities towards the installation 

Communication, Procedures, and Integrity. These are responsibilities that are so important in the installation phase. Let me explain:

It is a must to assure proper communication among the Design, Engineering, and Installation teams. We know there are constant challenges to keep the installation work to be on time and within specifications. The teams must have constant communication to be able to solve any difficulties or changes. In the real world, not everything fits as it fits on the drawings. I think many of you have experienced this, right?

Installation procedures must be created according to design specifications and every member of the team must be familiar with them. Depending on which industry, the procedures will differ from each other. It is not the same thing to perform the installation in the nuclear plant compared to the pharmaceutical industry. There should always be a reference to which specific standard belong to the site where the installation is taking place. API Recommended Practices for Machinery Installation and Installation Design (API 686) are the perfect foundation to start with.

Integrity is an important part of the installation phase and it starts with Safety. Everyone who participates in the installation must go through safety training. Specific trainings must be performed such as working in heights, confined spaces, fire protection, or chemical handling. Breaking the safety rules will put the project behind the schedule therefore it is very important to follow them.

Always do things in the right order 

The installation of rotating equipment must follow a certain order. The order of the installation procedure is designed to always start from the base. Foundations are the cornerstone of the entire installation. They are designed to hold rotating machinery and transfer and dissipate stresses and dynamic forces produced by pulsations and processes. Therefore, special attention must be paid to the foundations. They must be flat, coplanar, and levelled. If we skip the order of the installation procedures, we will not be able to complete further steps and not achieve reliable operation of our rotating equipment.

Finally, all the work must be properly documented during the process by creating digital reports to be able to review and compare the values and data. This is important for the references because further work will depend on the results.

Thank you Roman Megela with Easy-Laser for sharing this informative article with us!

Download our 5 Elements Machine Installation infographic which outlines 5 important elements of machine installation including Foundation, Anchoring, Isolation, Baseplate Level and Flat plus Alignment.

What is Machinery Installation And Why is it Important?

by Diana Pereda

Machine Shimming

MYTH: “You should always do your shimming first and then make your horizontal moves.”

TRUTH: This is generally true for the final alignment after soft foot has been corrected, but is not universally true for all alignments. In fact, for the initial rough alignment, you should correct the plane with the largest misalignment first, even if this means making a horizontal move first. Reason: If you have gross misalignment, you could be binding the coupling, deflecting the shafts, and imposing undue load on the bearings. By relieving strain from excess misalignment, a truer picture of the alignment condition emerges, and you eliminate an important outside force that creates machine frame distortion (soft foot).

Therefore, the correct sequence of events in any alignment job is:

  • Safety: Lockout & tag out plus clean up
  • Rough Align
  • Find, diagnose, and eliminate Soft Foot.
  • Final Alignment: shimming first, then moves.

Download our 5-Step Shaft Alignment Procedure a simple and effective procedure for shaft alignment of rotating equipment. 

The 5 Do’s and Don’ts of Shimming

by Diana Pereda

Alignment KSB Boiler Feed Pump

There has been a lot of improvement because of the laser shaft alignment and laser geometric alignment systems. They help you to identify the failures in your machinery and eliminate them easily. That’s why it is always critical to make necessary alignment activities to keep your equipment working stably and consistently with accuracy, less effort, and less training. We can also use straight edge method for rough coupling and alignment or otherwise reverse indicator method which is sometimes affected by obstacles like vibration effects which can be used when the technician is experienced enough to know exactly what he is doing for accurate results. However, these methods are not as efficient and accurate as the use of the laser is.

The major types of misalignment are the offset and angular misalignment. The laser alignment is definitely faster and cost-effective but the use of this technique needs some training for good outcomes.

There are couple of very common phenomenon that occur while working in the workshops and they are:

  • Thermal growth in which some parts of the machines suffer expansion because of the over-running or heating mechanism which causes the problems of misalignment because of the change in relative positions of the parts due to the growth in the machine parts.
  • The secondary cause of the misalignment is soft foot which causes the distortion in the frames of the machines that are coupled directly to each other.

Now there are some steps that you can take to resolve these alignment issues. The first step is to lock out and tag out the machines to work for safety. Then you should clean the area around the machine feed. In the end, check for soft foot and then align the machines properly and recheck them if needed for surety. You should also document these problems that you found and resolving methods for specific issues according to ISO 9000. Preventative maintenance is always better for which your bases should be strong to avoid any soft foot failures in the first place. At best, what you can do is to buy the laser alignment equipment from the best vendors who can work with you when you need them and give the workers some training for best results.

You should always check for failures and correct them on a regular basis to make sure it’s the perfect alignment for longevity. Implementing a complete formal alignment procedure is always an edge in the field of reliability and maintenance.

Hear more from Alan Luedeking in this podcast by James Kovacevic to know where to start with precision maintenance and how to keep your equipment aligned to avoid common problems so you can increase productivity and efficiency.

5 Things You Need To Implement A Precision Maintenance Program

by Diana Pereda

Rotating equipment alignment may seem like a small detail, but it’s actually the foundation of a smooth-running operation. It all starts with ensuring that the feet of the equipment are flat and coplanar and that the baseplate they’re mounted to is also level and coplanar. Standards like ANSI/ASA Alignment S2.75-2017 have set strict guidelines for baseplate flatness (baseplate must be level to <10 mils/ft, coplanar to <2 mils and each foot must be flat to <5mils).  But even with proper manufacturing, installation errors can occur.

Picture this: a baseplate that was manufactured to be perfectly flat and coplanar, but due to poor installation practices, the baseplate is now twisted and deformed, causing soft foot issues that need to be corrected before alignment can even begin. This could have been avoided if the baseplate had been measured for flatness, and levelness after installation and properly grouted.  The differences between an improper and proper installation are quite apparent as shown in the figures below:

Improper Installation of a Pump and Motor
Improperly installed and maintained pump-motor assembly. Note the loose anchor bolts and absence of any grouting.


Properly Grouted Pump and Motor
Properly grouted pump-motor assembly


In the past, this required a separate crew or contractor to perform optical and laser tracker measurements. But now, with the Easy-Laser XT770G shaft alignment system, the complete rotating equipment alignment commissioning package, it’s easy for the same installation crew to perform flatness and level measurements prior to alignment. The measurements can be taken, corrected and documented using the same computer that will be used for the shaft alignment task, making the process more efficient and accurate than ever before.

Download our 5 Element Machine Installation Infographic to help you outline 5 important elements of machine installation including Foundation, Anchoring, Isolation, Baseplate Level, and Flat plus Alignment. 

Why Align Your Rotating Equipment?

by Diana Pereda

Just Use a Plate!

Sometimes, during installation, for one reason or another, the two machines just don’t sit right on the baseplates. From baseplate design issues or machine housing quality problems to poor installation practices, one machine ends up being significantly lower than the other. Let’s say, in this case, it is the movable machine (an engine being aligned to a pump). During the rough alignment process, the engine needs to be raised almost a half inch (500 mils).

Instead of using shims to lift the full amount, the best thing to do is to manufacture a soleplate to fill as much of the gap as possible. In the picture below the correction was roughly 425 mils. You can see there is one thick precut shim and two manufactured plates, all close to 0.120″. Best practices as indicated in our Shimming Infographic encourages you to keep the shim count under the feet to four shims or fewer.

Aligning the machine using shims

If you have resources available to manufacture a soleplate and the machine can remain down for the time it takes to fabricate it, the optimal option is to make a 3/8th-inch plate (0.375 mils) carefully milled to be coplanar (both faces parallel to each other) and shim the rest with two 25 mil shims. This would add up to 0.425″ needed for the vertical correction while keeping the number of shims low.

Alternatively, you can explore the option of lowering the Stationary Machine (the pump) or angling it downwards towards the engine slightly, but these solutions likely will be more difficult to implement than just making a nice soleplate for the engine.

Download our Shimming Best Practices Infographic which outlines 7 things to consider when using shims for machine installation or machine alignment plus Step Shimming.

The 5 Do’s and Don’ts of Shimming

by Adam Stredel CRL

5 Quick Questions on Alignment

Q1. Why is it necessary to look at alignment condition results at the coupling? Why can’t I just get my feet to within 2 thousandths to finish the alignment?

Because the numbers at the feet are only a rough guide to the actual alignment condition.  Large corrections at the machine feet don’t automatically point to a misaligned coupling, in which case you are spending more time than necessary on an alignment.  The opposite can also be true.  Small corrections at the feet don’t automatically mean your alignment at the coupling is good either, in which case you are bolting down a misaligned machine.  The coupling is where we want to establish the true alignment condition. Not only is this the point of power transmission but it is also the point where the alignment condition is displayed and specified, and where it can be easily compared to tolerances. Of course, a very experienced aligner, with a good sense for the geometry of the machines, can glean an insight into the alignment condition from the correction values at the feet, but unless precise Rise/Run calculations are performed, the actual alignment conditions at the coupling will not be immediately apparent.

Q2. Why is the coupling our focus?

Two shafts with excessive offset between them at the coupling lead to premature wear and tear of bearings, seals, etc., along with a decrease in efficiency, increased power consumption, increased vibration, and other harmful consequences.  The driving machine transfers power and torque to the driven machine via the coupling, not at the machine feet.

Q3. The numbers are so small! How can the machines be misaligned?

Let’s look at an example. In Figure 1, the front and rear feet correction values are both 2 mils but with opposite signs.  The distance from the coupling center to the front feet is 10 inches and so is the distance from front to back feet.  Keeping your feet values in mind, the alignment at the coupling would not look so good.  See Figure 1:

coupling misalignment
Figure 1

This demonstrates why solely using feet correction values to determine the state of an alignment can be so misleading.  Our feet corrections are by no means large, yet the alignment is not within tolerance.  Always look at the numbers at the coupling. One method of expressing misalignment is in terms of allowable offset at the coupling center, and angularity between the shafts.  Neither alignment condition nor alignment tolerance should ever be notated only by using feet values.

Q4. Can you give me any guidelines or tips that I could use when looking at just the position values for the feet?

In the field you may get bolt-bound or base-bound or come across a machine that is difficult to align.  Therefore, it is always advisable to seek out the smallest moves possible necessary to achieve an alignment within tolerances. To efficiently rough-align the machine as well as possible, get the front feet position as close to the offset tolerance as you can.  Finish the alignment by correcting the rear feet, with the goal being to decrease the offset at the coupling center or center of power of transmission points.  Make sure that the signs (+ or –) of the feet correction value match, and that the back feet correction value is greater than that of the front.  Examples: Front foot positive? Then back feet more positive. Front feet negative? Then back feet more negative.  See Figure 2:

alignment coupling correction
Figure 2

In Figure 2, the feet correction values are greater than those in Figure 1, yet the alignment is better, still within tolerance at the coupling.  The offset between the shafts decreases as we approach the coupling, so that the offset falls within tolerance by the time the shafts meet at the coupling.  The other parameter that must be controlled is Angularity.

Figure 1 is not within tolerance because leaving the front and rear feet with opposite signs makes it more likely to have a large offset at the coupling center.  Having a greater correction value at the front feet also makes a large offset more likely even if both feet have the same sign.  Both of these cases could be described as pointed away from the coupling, the opposite of what we want.  This applies to both the vertical and horizontal corrections.

Q5. Any final thoughts on alignment tolerances?

We have tolerances because a perfect alignment is unattainable and unnecessary. It is only necessary to get the alignment “good enough”. Tolerances define what good enough means. One way to define that tolerance is by specifying the maximum allowable offset at the coupling center, as well as the maximum allowable angularity between the two shafts. This cannot be done with feet correction values without also specifying all the relevant distances like the distance between the front feet and the flex planes of the coupling.  Doing this requires you to process more information and is not as simple as using the coupling values.  The distances in question will vary from machine to machine.  Focusing on the alignment condition at the coupling allows us to understand more with less information.  The best laser alignment systems perform their tolerance evaluation based on the condition displayed at the coupling and compare it to the standards for the operational speed of that machine.  The higher the RPM of the machines, the tighter the alignment should be at the coupling.

Check out our Easy-Laser XT Series, with built-in alignment tolerances giving the user the freedom to choose between traditional tolerances, the new ANSI standards, or custom tolerances of the user’s own choosing.

Shaft Alignment Tips to Get Within Precision Tolerance

by Diana Pereda

Machine thermal growthWhen a machine heats up and starts expanding in all directions is simply called thermal growth. When it actually comes to understanding it, it means that you are dealing with machinery movement and that can cause misalignment in the machine. Also, your alignment is only as good as your target. If your machine starts moving and you have a bearable misalignment in the off-set condition, you will allow that bear minimum of misalignment in your machine deliberately in that condition. So, before you detect thermal growth, you need to have a correct target in place to measure it against.

In this episode, we focus on the following points:

  • What is thermal growth?
  • What are the standards of thermal growth measurement?
  • What packages are available that come with laser alignment tools?
    And much more!

When two machines are running in parallel with each other and one machine starts moving in the operating condition, it will cause misalignment between them. In those conditions, you might have shaft misalignment—machines are not aligned at the coupling point—in those operating conditions. Operating conditions are very important and you need to know what’s happing with your machines. Only then, you will be able to measure your targets, set them right, and make templates out of those. Once you have the correct targets in place, you can measure thermal growth against them and always document your findings for future reference.

When you start with thermal growth measurement, there are different standards out there. You can always check vendors’ operating manuals or bring in consultants for their expert opinion to get going but you need to have a proper understanding of what is going on with your machines to incorporate them correctly into your business processes. There are many different aspects that you need to look at when you are measuring thermal growth but common causes include piping, off-set gearboxes, and shaft misalignment. There’s technology out there that helps you calculate things while live machine operations and allows you to predict things well ahead of time.

There are different packages out there that come with laser alignment tools. You can benefit greatly from them and if you can properly calculate the thermal growth right, you can easily eliminate it. The operating context of the machine matters the most to successfully eliminate issues with your machines. So, it is always better to train your machine operators about the operating conditions and operations manuals for running the machines. They also need to have the right sense of misalignment and its direction before you deploy any procedures or make use of your valuable resources.

The best practice would be to be aware of the machine’s movement at all times and record those movements to have data to work with. There are advanced tools out there that can help you get rid of issues with your machines but you need to acknowledge the issue first, use the resources you got to deal with it, and enlist the expertise of consultants if needed. Over a period of time, you can make it part of your reliability programs and incorporate these practices in your business procedures to avoid any problems in the first place.

Hear more from Daus Studenberg in this podcast by James Kovacevic and better understand Thermal Growth.

by Ana Maria Delgado, CRL

What is a Pump?

Pump motor set
Photo courtesy of JetTech Mechanical LLC.

A pump is a machine or device designed to move and transfer fluids. All pumps basically do the same thing, and the pump best suited for your needs depends on how far, how fast, and how much fluid needs to be transferred. Pumps are very critical to a facility as a whole and unwanted downtime can cause production to cease. There are many manufacturers of pumps such as Goulds, Sulzer, and Sundyne to name but a few.  Monitoring a pump with a handheld vibration data collector such as BETAVIB’s VibWorks or using an online condition monitoring system like a Cortex system, enables a facility to save money and avoid unplanned downtime.

Many different mechanical issues can cause a pump to fail. Fortunately, machine data is stored in VibWorks software, which provides additional capabilities for programming, trending, evaluation, and archiving of the machinery condition.  Vibration monitoring allows for many things to be recorded such as:

  • Looseness
  • Misalignment
  • Bearing Defects
  • Imbalance
  • Pump Cavitation

One of the most important things to remember about a pump is the size needed for the application. Too many facilities have either oversized or undersized pumps, which can cause the pump to run above or below its ideal pumping curve. The pumping characteristic is normally described graphically by the manufacturer as a pump performance curve. The pump curve describes the relation between flow rate and head. A pump running off its intended curve can cause damage and result in poor performance.

Laser Alignment for a Vertical Water Pump with Easy-Laser XT

by Ana Maria Delgado, CRL


Most every running asset – no matter the mechanism used when coupled together – can be subject to misalignment between driver and driven components. Proper alignment of belt-driven equipment is often neglected by maintenance and even reliability departments even though pulley misalignment is a principal reason for reduced belt life, premature sheave wear, and higher than necessary power consumption.

Alignment of a belt drive
Photo courtesy of JetTech Mechanical LLC


With today’s strict reliability requirements, the best method to utilize for belt alignment is a laser alignment instrument designed for this task. In addition to providing an extremely accurate, cost-effective, and time/labor decreasing process, there is the added bonus that some tools available on the market also offer a detailed report of the work performed, including photos which can be archived for future reference. The Reliability and Maintenance group can easily be trained to incorporate proper belt alignment procedures such as that presented in LUDECA’s 5-Step Sheave/Pulley Alignment Procedure into their maintenance intervals. The ROI with these types of instruments is very quick; this will allow savings and profits to rise almost immediately.


Belt alignment systems for this task such as the Dotline Laser, SheaveMaster, or SheaveMaster Greenline laser pulley alignment tools are good. They indicate misalignment in all three degrees of freedom (axial offset, horizontal angularity, and twist angle) instantly. However, systems like the Easy-Laser XT190 take it several steps further as the instrument communicates with either the XT11 tablet or to any smartphone/tablet via Bluetooth with the Easy-Laser XT Application and displays all this information live on a screen as you are performing the corrections. Upon completion, the system provides you with a full report.  A maintenance or reliability technician can easily determine and correct belt alignment conditions in a short period of time.

Remember that for any tool you use, always ensure that the mounting surfaces (pulley faces) are free of dirt or rust, and don’t forget to verify the proper tension of the belts has been set after the alignment.

Defects related to belt alignment issues can have a severe impact on the reliability of your assets. Be proactive and take advantage of best-practice belt alignment techniques to increase your uptime and the life of your assets.

Now You Can Detect and Quantify Belt Driven Rotating Equipment Defects!


by Ana Maria Delgado, CRL

Two men measuring machine base

“Reliable machinery installation” – it sounds like an obvious thing, don’t you agree? But where does reliability actually start?

We all know that “the thing” starts with the design. The design stage decides what is going to be installed. Which equipment, and where. But there is no decision on Who is going to perform the installation, and How it is going to be installed. Most of the time those two departments are not cooperating, especially if they don’t belong to the same organization. The installation teams must be involved in the design because they will provide their feedback for reliable machinery installation. They know exactly how things work out there and how they need to be done.

Every day I see on social media tons of information regarding reliability maintenance, condition monitoring, sensors, cameras, and all possible problem-solving technologies. All those technologies provide the necessary information from our assets. Things we need to know in order to evaluate the condition of our assets. But what about the most crucial step? Machinery installation, anyone? I have been assembling and building skids and gas compression systems for the gas and petrochemical industry for many years. My experience has shown me that “flatness and levelness” is one of the most critical issues when it comes to the assembly of rotating machinery.

Designed for flatness and levelness

All machinery is designed to work on a flat and leveled surface. Every manufacturer of pumps, compressors, blowers, electrical motors, and gearboxes assumes that their equipment is going to be installed correctly, meaning on a flat and leveled surface. And they also provide their tolerances for this. There are standards for the installation, too. ANSI standards recommend foot flatness less than 0.4µ/mm [5 mils/ft]. And coplanarity is less than 50µm/mm  [2 mils] between the machines and their drives for machines up to 400kW or 500 HP. ISO standard for centrifugal pumps for petroleum, petrochemical, and natural gas industries (ISO 13709:2009) says clearly that “Corresponding surfaces shall be in the same plane within 150µm/m”.  That is 0,15mm per meter. Levelness has the tolerances less than 0,8 µm/mm [10 mils/ft].

Bent base frame
Bent base frame

Flatness and levelness affect everything

Checking the flatness of the foundation is essential. The foundation is the cornerstone for every single installation, irrespective of type. Mounting pads, soleplates, frames, and tables. Everything you put on top of them is going to be affected. When the flatness is out of tolerance all rotating equipment is affected. Soft foot, misalignment, machine casing stress, pipe flange misalignment, and many other causes. But I want to mention specifically one, and that is a strain in the bearings. The bearing is designed to rotate using the oil film lubrication. According to Swedish bearing manufacturer SKF, a free-running bearing with the proper lubrication will rotate to infinity. When the bearing is squeezed, the lubrication film is forced out and contact metal-to-metal appears. Excess heat is generated, and your bearing is running into failure. That simple. All other failures will be linked to it. And it often started with a flatness issue. Levelness is another factor affecting heavily the equipment. Vertically installed bearings carry on horizontal loads and if you change their gravity point, the lubrication will move out of their raceway. If you don’t have proper lubrication film, there will be metal-to-metal contact. If you have splash lubrication in your machine, and you have unlevelled installation, you will move the oil away from the oil slinger. That will be the end of the story.

Why would you install your asset on bases which are not checked for proper flatness and levelness and face all the problems related to it? After reading this you can at least not claim “I didn’t know it was important…”

Soft foot condition
Soft foot
Flange misalignment
Flange misalignment

Thank you Roman Megela with Easy-Laser for sharing this informative article with us!

What is Machinery Installation And Why is it Important?

by Ana Maria Delgado, CRL

A topic I like to highlight and elaborate on during a training session is alignment tolerances. In my experience, I have found that most people involved in alignment don’t give tolerances much thought. Alignment tolerances are useful in that they give the technician doing the alignment a stopping point. But tolerances can vary widely: From coupling manufacturers whose tolerances are as wide as the Grand Canyon, to company X’s engineer who years ago decreed all alignment should be under 2 mils at the feet, the question is always asked: Which alignment tolerances should we use?

Today, most laser alignment tools have some sort of tolerance table built-in that is adjusted to the speed of the rotating equipment being aligned, along with some sort of indication that the value has been reached. Also, in recent years the American National Standards Institute (ANSI) developed (with the help of “alignment gurus” in the industry), a set of alignment tolerances for rotating equipment. In the case of our Easy-Laser XT systems, both of these options are built-in. The user can choose to use the default tolerances or a national standard for alignment tolerances. Both are close in their values. Below is an example of the ANSI standard for common RPMs, offering Minimal, Standard, and Precision tolerance values, for the parameters they named: Offset and Angularity Method.

Shaft Alignment Tolerance Table

Let’s assume that the machine being aligned runs at 1800 RPM. The precision offset tolerance, in this case, is 1.6 mils (0.0016 inches). In the case of the Easy-Laser XT systems, the tolerance indicator is color-coded to each of the three options (Minimal in orange, Standard in yellow, and Precision in green.)

The point I like to emphasize in my training is, what happens when the final measurement shows the alignment to be at 1.8 mils of offset? The tool will not show green for the offset tolerance. It will instead show yellow because it is outside of the 1.6 mil threshold. But let’s think about what’s actually happening. The alignment is essentially 0.2 mils (0.0002 inches) away from giving a green indicator. So, the question we need to pose is:

Is it worth the time and resources to loosen up the bolts and make adjustments at the machine feet to correct 0.2 mils of offset at the coupling center to achieve Precision alignment?

The answer depends on how difficult it has been to achieve the 1.8 mils. It also depends on the condition of the baseplates, residual soft foot, length ratios of the machine, and what other tasks are planned for the day. If the 1.8 was achieved after the first move, and soft foot was fixed relatively easily, then making another move to fall within the precision tolerance may not be that difficult. On the other hand, we need to consider the fact that in the attempt to improve this alignment condition, it could get worse. Therefore, if the technician has been dealing with a baseplate that pulls the machine upon torquing the bolts, has a residual soft foot condition, or is simply needed in another part of the plant, it may not be worth it to make that small of an adjustment.

This is the reason why I always recommend reviewing the allowable tolerances for the machine being aligned prior to starting the alignment. This way we shift our focus from striving to achieve zeros, to reaching a tolerance value that has been studied and proven to be good enough. In the case above, knowing that the value needed to achieve precision alignment is 1.6 mils, will aid in making the decision on whether to make that final move or not, because focusing on tolerance indicators can lead to time wasted in making machine corrections when those resources could be used on more important tasks.

by Adam Stredel CRL

We previously went over our glossary of alignment terms with, “What is Alignment? Check out our Glossary of Alignment Terminology from A-H!” and later with Alignment Terminology from I-R. 

In the world of alignment, there is a multitude of technical terms. We provide definitions for some of these terms that you might hear from an engineer or technician as well as read in reports and might need further clarification. We welcome you to check out our glossary of terms S-Z relating to alignment, and hope you find it valuable!

SOFT FOOT – A term used to describe any condition where tightening or loosening the bolt(s) of a single foot distorts the machine frame. Must be corrected prior to final alignment.

SPACERS – A generic term for any coupling characterized by two flex planes separated by a connecting shaft without bearings or other supports between the flex points.

SQUISHY FOOT – A type of soft foot characterized by material (could be shims, paint, rust, grease, oil, dirt, etc.) acting like a spring between the underside of the machine foot and the baseplate contact area.

STAT – A short form of “stationary machine”. The stationary machine’s centerline is used as the reference line to measure the misalignment of MTBM (Machine To Be Moved).

STEP SHIM – Use of several shims to fill the wedge-shaped gap of a bent foot. Each shim is inserted to a different depth so that a stair-step-shaped support is built to better support the entire foot. All of the steps together are called a step shim.

THERMAL GROWTH – Movement of shaft centerlines associated with (or due to) a change in machinery temperature between the static and operating condition.

Thermal growth on pump motor set

TOLERANCE – The maximum permissible deviation from a specified alignment position, defining the limits of offset and angularity.

by Ana Maria Delgado, CRL

Precision Maintenance can be used as a process improvement strategy. A strategy that will pay dividends. This process is easy to implement. In fact, you do most of the work already. The beauty of it all is that there is not a lot of cost involved and if you are smart, you can implement the process on one machine at a time.

Precision maintenance is not new, it has been in our company name BENCHMARK PDM for many years. We chose the word BENCHMARK because it means a standard by which something can be measured from. The acronym PDM stands for precision-driven maintenance. So, our goal has been and still is to set the standard for precision maintenance.

In simplistic terms, Precision Maintenance means working to a recognized standard tolerance or specification. Just doing that will improve your work processes, and the payoff is a much improved and reliable machine (asset). It is important to note that when I say recognized, it means the standard is approved by an organization such as the Canadian Standards Association (CSA), the International Standards Association (ISO), or the American National Standards Institute (ANSI). There are many used in the industry, a common one is the ISO 10816 vibration standard tolerance chart (see image below).

ISO10816 Table

Are there exceptions to using a recognized standard? Absolutely. There is the American Petroleum Institute API686 and while only a guideline and not a standard, this document was the go-to bible for anyone doing pump installations and still is.

When implementing Precision Maintenance there are five things that you should already have or need to have to be successful.

1. Work Procedures

Work procedures are written documents that follow the work process. You have them as part of your Preventive maintenance program. But do you have them for a pump overhaul? The procedure should include the standard tolerances and specifications you would need doing the work. What this would give you is consistency. If you do not have written procedures or old outdated ones, the best people to write them are the tradesmen as they know the work process the best. Better still, do it as a team-building exercise as it creates buy-in. However, they must be clear, with no ambiguity, all must understand and be on the same page.

2. Measuring Tools

Precision Maintenance requires exact measurement. Obviously, you need instruments that can achieve this. The actual recommendation is to use instruments that can measure under the tolerance you require. The tighter the tolerance the better the result but you cannot have a tolerance that you cannot measure. This means you need the right tools for the job. Always try to use digital so that the measured value or result is saved electronically. It is a known fact that when using instruments such as theodolites, dial gauges, or levels, for example, the greatest error occurs during the transfer of the seen value. My one piece of advice is do not buy junk. You need something that the team will use. Get them involved in choosing the tools required.

XT290 Level

3. Data processing system

This is so important because it gives you an organized structure. You probably have a PM program, which of course is a must, that is controlled by a CMMS/EAM system. In it, you will have planned work orders, backlog orders, PM schedules, CBM tasks, etc.

Depending on the capabilities of your CMMS/EAM you should have an individual file for all the plant’s assets. Each one should be a benchmark record of the machine’s normal operating condition. For example, the normal operating temperature should be known, and where you would take those measurements to verify this. Simple enough to do but so helpful for the PM tech. There should also be an asset history file.

And this is where we often see the breakdown in the system. There may be a file but what is missing from many is the asset/machines installation report or a coming into service report. This is the information that controls the reliability of this machine.  Imagine if you had to do a breakdown analysis after a failure and did not have this information. You would be relying on guesswork or maybe wrong information.

A Precision Maintenance program guarantees that you have this file because a precision machine installation has mechanical measured items such as these below. 

  1. Base flatness and level
  2. Shaft runout
  3. Coupling runout
  4. Pipe and conduit strain
  5. Soft foot
  6. Offline To Running (OLTR) machinery movement
  7. Shaft centerline to shaft centerline (alignment)

All of these items and the recognized standard tolerances/specs can be found in ANSI/ASA S2.75-2017/Part 1. An installation report and a commissioning report guarantee the machine has a good starting point when starting service. And throughout its life, there will be added work to this report such as “As Found” and “As Left” alignments or a base flatness change as things do move over time.

Tightening Pipe Flange Bolts
Tightening the pipe flange bolts and not pictured is an Easy-Laser XT770 laser alignment system checking for pipe strain live time (Photo credit: Brian Franks –

4. The right skill sets for the work

I had a conversation with a maintenance shop foreman who suggested that not everyone in the shop had the same-sized toolbox and that he would pick and choose who to put on what job. What he meant was that not everyone has the same skill set. For example, I know a company that bought an expensive and not-so-user-friendly laser alignment system. The problem is that not all the shop guys can use it. It may be taken to the job site but unfortunately not used correctly or not used at all. This is one of the reasons we are developing training videos to help support some tradesmen who struggle with new technology. They can take their time and review it as often as they like especially before going out to do an alignment job. With Precision Maintenance all should be proficient in taking and recording measurements. So, you may want to invest in training.

5. The right team culture

I first heard the term Precision Maintenance from Ralph Buscarello of Update international who is the gentleman that taught me shaft alignment using dial indicators almost 40 years ago. I have heard others promoting this as the next big thing. But the reality is that it has been with us for a long time. Some companies, not a lot, do it, others do it but not as successful.

If you are in maintenance, whether in management or skilled trades, embarking on such a program as this is challenging. It is a very worthwhile program, but it is a big commitment to do it and stay with it. The overall benefits are large in the form of machine/asset reliability. A side benefit is that you have to do this together as a group, dare I even say team, which does put some people off. However, there are different cultures that produce different teams. You may want to hug every morning before starting work, but others won’t. In today’s industrial environment it should be evident to all that we have to work together in order to compete. So, my advice is that you sit down collectively and ask some tough questions such as can we do this and what do we need?

In today’s world of Covid, we use scientific knowledge to help us make choices or decisions about our health. That is not unlike what you do with your Condition Based maintenance program where decisions are based on the measurement/data that is taken. It is the same with this program. It is data-driven. Quantifiable, reproducible measurements are taken, analyzed, and compared to a standard. Decisions and or actions are taken and the whole process is documented.  For well over ten years our training has been called MAAD which is an acronym for Measure, Analyze, Act and Document. I would suggest that you do something along the same lines as this if you want to improve your maintenance process. And quite simply do the job right. You are doing the work already.

Thank you to Benchmark PDM for sharing this blog with us!

What Impact Does Precision Maintenance Have On Your Equipment?

by Ana Maria Delgado, CRL

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