Spindle Tightener Guide

Spindle tighteners are closely integrated with spindle cappers to securely tighten caps on containers efficiently. The mechanical process needed to twist a cap onto a bottle is one that a person can perform without much thought, but to recreate the motions with machines requires a finely tuned balance of torque, speed and careful positioning of different components. The resulting increase in productivity, however, makes automating the process of tightening caps well worth the effort of making the initial adjustments.

How They Work:

After caps are positioned on top of the necks of containers, the spindle tightener uses gripper belts to draw the containers forward as the spindle wheels tighten the caps to the correct level of torque.

The Versatility of Spindle Tighteners

Spindle tighteners can handle almost any bottle type or shape including PET, PP, PVC, HDPE, LDPE, and glass. Because of their modular design, you can use them as the foundation of a simple capping system – adding just a cap tightener at first – and then over time add other automation capabilities such as a chute or automatic cap feeder as needed. In conjunction with a spindle capper, spindle tighteners can process over 50 bottles per minute.

Precision and Efficiency

Spindle tighteners assist in positioning bottles and applying the correct amount of torque to caps to ensure that containers are sealed securely, protecting the contents. This requires different components to operate together, while allowing for precise adjustments to be made depending on the specific needs of each job. These components include:

Gripper belts: Gripper belts hold the bottles in place as they are moved through the spindle capper. Spindle tighteners may use a single set of gripper belts for bottles with a simple shape, or a double set of belts for tall or irregularly shaped containers. The height of the belt placement is important for keeping the bottles stable, as belts that are set too low can allow wobbling, while belts set too close to the neck can prevent a good seal from forming.

The tension of the gripper belts also needs to be adjusted to the size of the bottles, as too much pressure can damage the bottles and too little pressure will allow too much movement.

Spindle wheels: Working in sets of 4, 6 or 8 matched spinning disks, the spindle wheels use the balance of speed and tension to create the motions needed to tighten a cap onto a bottle. Automating this process prevents the repetitive strain injury that a human capper would experience, while greatly increasing productivity and consistency. The functions of cappers and tighteners work together most closely at this stage.

When more than a single matched set of spindle wheels are used, each one will be set slightly lower than the one before it to account for the downward-spiraling movement of the cap as it is tightened on the bottle threads. As with gripper belts, too much tension can cause damage to the packaging, and too little tension will fail to tighten the caps sufficiently.

The settings for both gripper belts and spindle wheels can be easily adjusted by an operator to accommodate different jobs. The team at Apex is also on hand to help you determine which settings work best with your containers.

Industry Applications

  • Personal care
  • Nutraceuticals
  • Cosmetics
  • Beverages
  • Pharmaceuticals
  • Household chemicals
  • Petroleum products


  • Heavy-duty 304SS free standing frame
  • Easy integration with most conveyor configurations
  • Variable speed industrial grade motors
  • 4, 6 or 8 spindle wheels
  • Spindle wheel adjustment knobs with locks
  • Gripper belt height and width adjustment
  • Removable dual gripper belts on 6 and 8 spindle models
  • No change parts required for a wide range of containers
  • 303 stainless steel drive shafts and adjustment support shafts
  • Adjustable spindle clutches on final set of tightening spindles
  • Power height adjustment available on 6 and 8 spindle models
  • Tool-free changeover
  • Made in the USA

Customization Options

Additional options include:

  • Cap sorting device – vibratory bowl
  • Cap sorting device – centrifugal bowl
  • Cap sorting device – sorting elevator
  • Trigger sprayer cap rails
  • F-style spacer
  • Reversible first spindle set (on 8-spindle capper)
  • Dual gripper belts
  • Hazardous location/environment construction – Class I, Division II, Groups C&D


The Apex team will also be on hand to assist with the maintenance of all of our packaging solutions, including providing replacement parts, troubleshooting, and readjusting controls to accommodate different containers. Feel free to reach out to us if you have any questions regarding the spindle tightener guide.

Let Apex Help You

Apex offers all of our clients customized solutions to their filling and capping needs. Call us at 219-575-7493 or visit our page here to discuss the best equipment choices for you.

Integrity, honesty, and a dedication to delivering ambitious results serve as the central themes of Alicia’s career and are evident in every interaction she has with our clients. Her relationship-centered leadership style has paved the way for Apex Filling System’s culture of compassion & empathy, executed with accountability that ensures consistently great outcomes. As a learner for life, her pursuit of continuous personal and professional growth has led Apex Filling Systems to be recognized as an industry innovator in customer experience. Holding advanced degrees in the areas of engineering and management, she has a unique ability to analyze processes, identify potential problems before they arise, and develop standardized solutions to ensure every client of Apex Filling Systems enjoys a hassle-free, professional, and pleasant experience. Her leadership style has been influenced by the work of some of the most well-regarded thought leaders throughout the last 50 years. Among them are Jim Collins, Sally Hogshead, John Maxwell, and Tony Robbins.