Mill Alignment Reveals Structural and Shim Challenges

Over the years, Roll-Kraft has conducted thousands of mill evaluations on a variety of equipment. We are now sharing these stories in our Tube & Pipe Field Service Report Article Series. We hope you find the information contained in this series helpful. If you have any questions regarding your mill, use our contact form to request more information about our on-site mill evaluation.

Problem: 
During a scheduled alignment of a Rafter tube mill, operators identified persistent alignment issues in the stands and structural inconsistencies that had been affecting production accuracy and reliability.

Challenge: 
Several stands showed signs of twist and misalignment, which compromised the precision of shaft shoulder positioning. Further investigation revealed that many of the stands had excessive or insufficient shim material, as well as damaged shims including torn or folded components with debris contamination. These defects made it nearly impossible to consistently align the shaft shoulders, a critical requirement for ensuring uniform tube dimensions and reducing wear on tooling.

Solution: 
Using laser alignment technology, the Roll-Kraft technician brought all shaft shoulders in the breakdown, fin and sizing sections into precise alignment. Special attention was required in stand #4, where shim misconfiguration had caused the shaft shoulders to drift significantly from the centerline. A fresh shim stack was calculated and installed based on exact component measurements. In addition to realigning the mill, the technician provided a comprehensive procedure for rebuilding bearing blocks. This included detailed steps for measuring and calculating shim requirements, proper assembly techniques, including proper preload of taper roller bearings, and diagnostic tests to confirm correct alignment. These best practices will help the maintenance team prevent future alignment problems, reduce downtime, and maintain high production standards.

Contact Roll-Kraft for a Tube & Pipe Mill Evaluation
Do you have issues you would like a second opinion on regarding your mill? Roll-Kraft on-site evaluations really make an impression with your staff, confirming you are serious about producing quality tube, pipe, and roll form products. Our technicians will tell you exactly where you are currently doing a great job, in addition to pointing out any areas that could be improved. We have been doing training and evaluations for over 30 years and understand the sensitive nature of bringing someone in to talk about improvements. Your staff will be in good hands with Roll-Kraft. Click here to learn more about our tube & pipe evaluation service.