Training-Focused Mill Evaluation Reveals Shaft Wear and Setup Gaps

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: 
As part of a plant-wide training program, Roll-Kraft conducted a full evaluation of a tube mill installation that had been operating without formal instruction or setup standards. While the crew had done an admirable job establishing the line, they were beginning to experience issues with weld integrity, roll wear, and mechanical repeatability.

Challenge: 
Numerous technical gaps were identified during the evaluation. The payoff reel had bearing issues and was misaligned, causing the strip to contact the arms and damage the edge — a critical concern for weld consistency. The end weld splices were sometimes misaligned, creating catch points in the accumulator and downstream passes.

Within the mill, several key components exhibited mechanical instability. The entry guide had excessive backlash, requiring a half-turn before movement, and the side-to-side adjustment relied on brass washers rather than thrust bearings. Multiple driveshafts were found out of phase — in some cases by 90 degrees — which affects roll RPM and profile control.

The inboard bearing blocks showed slot wear where they engage with the stands, compromising shaft alignment. Visual inspection and micrometer measurements also confirmed that several driven shafts were worn below spec in areas where the tooling rides, resulting in loose roll fits. These mechanical issues were compounded by a lack of inspection tools, measurement instruments, and proper setup documentation.

Solution: 
The Roll-Kraft team provided both hands-on training and mechanical recommendations to establish a reliable foundation. The entry guide was adjusted for better centering and operators were instructed on how to use thrust bearings and split lock nuts to improve stability and reduce backlash. Worn shafts were flagged for hard chroming or replacement, and technicians explained how to inspect, preload, and document driven shaft integrity using inch-pound torque wrenches.

To improve consistency across sizes, Roll-Kraft emphasized the need for solid setup plugs for the weld box and Turks head unit, complete with profile measurements and rim clearance targets. Pressure settings were validated using solder tests across all breakdowns.

A list of recommended tools — including Starrett straight edges, digital micrometers, depth mics, and dial torque wrenches — was provided to build a proper setup station. Operators were also instructed in the use of piano wire and shoulder alignment tools for verifying parallelism and alignment across the mill. These combined efforts brought immediate improvements in strip tracking, weld quality, and setup repeatability.

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.