USA - With decades of rigging expertise, KDH Precision ensures both successful performances and the safety of all involved. Since 2017, the company has provided rigging services for Metallica and collaborated with numerous A-list acts and major events. Founded by Chad Koehler, one of the industry’s most experienced and recognised rigging specialists, KDH Precision continues to set the standard for excellence in rigging and safety.
KDH Precision has worked closely with artists such as Rihanna, Beyoncé, The Rolling Stones, Shania Twain, Carrie Underwood, Kid Rock, and most recently, Chris Stapleton and Zach Bryan.
"With the ever-growing complexity of production spaces, ensuring the safety of fans, staff, and talent has become an escalating concern. The use of advanced technology, coupled with the increasing size, weight, and dynamics of shows, as well as the rise in outdoor performances, has exposed the often-overlooked dangers of overload," explains Koehler, who has relied on Eilon Engineering load cells to meticulously monitor loads for the past 15 years.
When working with a show design, KDH collaborates with staging and production companies to determine the most effective monitoring system required for safe load handling. Koehler says the number of load cells necessary varies depending on the design. “For the current Metallica tour, we worked with StageCo and Tait to determine the number of pick-up points and load dispersal,” he said. “Once we knew how many screens we had, we then put the load cell system together.” To cover the Metallica M72 world tour, KDH Precision acquired 130 units, including 120 active load cells and 10 spares.
As Metallica's head rigger for the past eight years, Koehler and KDH Precision has played a key role in numerous high-profile shows, including the band's 2017 WorldWired tour - a massive 100+-ton production featuring kinetic LED cubes, with safety ensured by 40 load cells. KDH also contributed to the S&M2 performances and the band’s 40th Anniversary shows.
KDH initially employed Eilon load cells in 2008 to monitor a large locomotive train set piece that became an iconic visual during AC/DC's two-year Black Ice world tour and has used Eilon load cells on a previous Metallica tour. Impressed by their performance, the decision was made to use the Eilon system again for Metallica's M72 tour.
Given that M72 is an extensive outdoor production, it presents several challenges. The setup involves eight towers comprised of 30-ft tall circular LED screens, which are essential components of the design. To monitor the screen loads from setup to tear down, KDH relies on Eilon Engineering's Ron StageMaster 4-ton G4 wireless load cells.
Each tower features three screens, and each screen has five motor points, resulting in a total of 120 points that can be monitored. Koehler explains, "When you have a significant number of hoists positioned closely together, maintaining perfect levelness to the ground becomes challenging.
“Even a slight deviation of half an inch can affect the applied load on the structure above. When we have five hoists supporting one-third of a screen, and a total of 15 hoists collectively, a difference of half an inch to an inch can lead to significant swings in weight distribution. You can’t tell by just looking at it. We need to precisely know the load, and the only way to achieve that is through our Eilon system."
While the different forces on a load must be managed in any setting, the importance of monitoring is particularly magnified in outdoor shows, where adverse weather conditions, especially wind, can destabilise the rig. “In a controlled arena setting, my focus is more about adapting the show so it looks exactly like it did in the previous city. It involves dealing with scoreboards and staying within the structural tolerances. However, in an outdoor show, where all the gear is exposed, the working environment becomes more challenging.
“The wind can be the real enemy when we’re trying to get all the elements in place and then down again,” Koehler emphasises.
While raising and lowering the screens on the M72 tour, precautions are taken to ensure stability, but the wind remains a formidable challenge. Koehler elaborates, "The wind exerts additional force and load on the structure, and the screens can act like sails. Every element has tolerances, and load cells allow us to stay within those limits when dealing with such big moving objects."
To monitor the 120 load cells, KDH Precision employs a portable Ron StageMaster PRR receiver in conjunction with an iPad. The wireless system allows him to view load maps while moving around the stadium. The load cells transmit data via radio frequency to the PRR (Portable Radio Receiver), which serves as a handheld, Bluetooth-compatible load monitoring system.
If the load approaches the overload or underload limit, the system triggers an alert, prompting immediate adjustments to ensure safety. Additionally, a close eye is kept on weather forecasts and wind conditions using anemometers installed atop the structure.
"I have complete confidence in the calibration, up-to-date status, and reliability of the equipment I have," Koehler affirms. “The load cells not only allow us to perform our job safely but it's a win-win for everyone involved. Among the various systems we have used, I find Eilon's load cells the most user-friendly in terms of manoeuvrability, installation, and dismantling. The battery life is exceptionally long, and the load cells are remarkably energy-efficient. They also provide excellent support, assisting with technical aspects and updates whenever needed and they have been instrumental in helping set up systems for each tour."
