A couple of months ago, we were hired to perform an alignment on a motor/gearbox setup with a 9-foot spacer coupling in between. The obstacle this time around was that the spacer coupling was going through a steel support beam. The coupling is round but the hole in the beam was square, just big enough for the coupling to go through. With a circle going through a square, only the corners of the hole were open. This meant that line-of-sight between the two lasers was limited. Because of the obstruction there was no way to obtain data with a continuous reading. Using our dual-laser XT660 system, we decided to take readings in each available corner. We could have taken one point at each 45 degree position. However, taking more points is always beneficial. We decided to take three points (close together) in each of the corners. With two rotations, we obtained excellent repeatability. Once we had repeatable readings, we moved the machine according to the calculated alignment results and aligned it to our customer’s customized tolerances.


Many times we are faced with awkward alignment situations. It is helpful to have an alignment tool that is very easy to use, yet versatile to adapt to these situations. It helped that the Easy-Laser® XT660 allowed us to change measurement modes (in this case to Multipoint mode). It also helped that the tool allowed us to adjust our tolerances to the customer’s particular needs. The customer did not want to use the built-in Easy-Laser tolerances, nor the ANSI standard tolerances that are included in the system. Instead, they were looking to align the machines to within 0.1 thou/inch (or 1.0 thou/10 inches) of angular misalignment at each flex plane. So we created a custom tolerance instantaneously within the tool for this job. The customer was satisfied with the alignment and the report generated with their tolerances.

Learn more about Precision Alignment from Adam Stredel at our Rethink Maintenance Training Roadshows

by Ana Maria Delgado, CRL

It can be argued that lubricants are the lifeblood of equipment. It is extremely difficult to assure equipment reliability when lubrication integrity is not maintained. The key is to keep the lubrication system clean, cool and dry.
According to the Arrhenius Rate Rule, every 18-degree (F) increase in oil temperature in operation reduces oil life by half. Excessive lubrication temperatures can lead to additive depletion, oxidation, varnishing, hazards, corrosion, increased frequency of oil changes and more. All of this leads to reduced equipment reliability and increased costs.
Reduced operating temperature is one of the many benefits associated with proper machinery alignment.  This in turn will help you reduce the operational temperature of the lubricants (lifeblood) within your equipment.  Best practice equipment reliability includes proper equipment alignment. Your best practice lubrication efforts should include making sure your equipment is operated within proper alignment tolerances. Doing so will help you maintain the “cool” required to ensure that the lifeblood of your equipment is protected.

by Trent Phillips CRL CMRP - Novelis

When performing shaft alignment,  the most important goal is to align the machine to within proper tolerances. One criterion that has an impact on the tolerances that should be used is identifying and selecting the correct coupling type. In the setup shown below in Figure 1, spacer coupling tolerances were being used. However, in order to achieve a proper alignment, the alignment should have been performed using the short flex tolerances. Between the two shafts, a long coupling is used to connect them, however the connection between the motor shaft and the spacer (Left side in picture) is rigidly coupled and has no flexible element. Thus this setup should be treated as a continuous extension of the motor shaft. Therefore, the alignment should be performed using the short flex tolerances at the flexible coupling on the right side. Spacer tolerances should only be used when the distance between the two flex planes of a coupling is four inches or greater.
Rigid Coupling
For a more detailed explanation of using the spacer tolerances, watch our Spacer Shaft Alignment Crash Course Video.

by Tim Rogers CRL

Standard vs. Vector Tolerance Evaluation

If you are aligning very critical machines and your laser system does not offer you the ability to apply vector tolerances, you can still do so manually, by keeping these criteria in mind:
The standard industry norms of 2 mils offset and 0.3 mils per inch of angularity at 1800 rpm equate roughly to vectors of 1.4 mils of offset and 0.17 mils per inch of angularity. Therefore, you can apply a sliding scale when you look at your misalignment results: If you have misalignment only in one plane (either vertical or horizontal), apply the full value of the standard tolerance; if you have roughly equal misalignment in both planes apply the more conservative values shown above to both. This way you will not exceed your vector limits in any direction. To find the vector limits for any RPM, simply take the square root of the standard limits.
Of course, none of this would be necessary if you have one of the better laser systems that features vector tolerances and calculates them for you automatically.

Download our paper about Alignment Tolerances.

by Alan Luedeking CRL CMRP

Ludeca, Inc. presents “Laser Align“, a free reference tool for shaft alignment of rotating equipment. With this app, you can access important reference material and learn about key laser shaft alignment concepts. “Laser Align” features the demanding tolerances that have been the industry norm, pioneered by Ludeca in 1983.  These exact same tolerances are used throughout our Laser Shaft Alignment product line.
Laser Align features the following tools with helpful reference guides:Laser Align iPhone App
– Short Flex Tolerance Table
– Spacer Shaft Tolerance Table
– Thermal Growth Calculator
This app offers interactive links for additional information on Pruftechnik laser shaft alignment products such as the Rotalign Ultra, Optalign Smart, Shaftalign, Aligneo. It also features links to Pruftechnik’s condition monitoring products such as the Vibxpert, Vibscanner and Vibnode.
Click here to download the FREE Laser Align iPhone/iPad App Today!

by Yolanda Lopez