Fixture Plate Guide: Mounting Versus Threaded Holes

Categories: Modular Fixturing

Fixture plates are tools that help increase process repeatability. They are designed to hold a wide array of components like clamps, manifolds, and thumb screws, which reduces time spent switching between components. All fixture plate designs include evenly-spaced threaded holes, but there are some fixture plates that come with mount holes, too. 

In this article, we’ll cover everything you need to know about mounting holes and threaded holes.

What Are Mounting Holes?

Universal mounting holes are through-holes bored into fixture plates at precise locations to accommodate fast and easy mounting to machine beds. They also help maintain exact positioning of a fixture plate during machining.

Rayco recommends mounting holes for all coordinate measuring machine (CMM) applications that demand ultimate precision and repeatability. CMM machines are available in different sizes and mounting configurations, so be sure to make notes of the year, make, and model of your coordinate measuring machine when ordering a custom fixture plate.

Threaded Holes

All of Rayco’s fixture plates come with threaded holes. Grid-style modular tooling plates feature both threaded and unthreaded holes that support exact positioning and repeatability during machining. The threads in these holes are protected when not in use by short like-threaded cap screws that you remove when you need access to a specific hole.

Rayco’s tooling plate threading options include:

  • 1/4-20 (0.25-inch Diameter With 20 Threads)
  • M4 (4 Millimeter Major Diameter)
  • M6 (6 Millimeter Major Diameter)
  • M8 (8 Millimeter Major Diameter)

Additionally, tooling fixture plates feature an alpha-numeric coordinate system engraved on the bottom and left side of the plate, allowing the operator to identify each hole quickly and accurately. The numbers and letters enhance efficiency and organization in the manufacturing process, allowing the operator to keep track of each component in a multi-part manufacturing setup.

Threaded Holes Versus Mounting Holes

The primary difference between threaded holes and mounting holes is their purpose on a fixture plate. As previously mentioned, universal mounting holes are what operators use to fasten the fixture plate onto the coordinate measuring machine (CMM) or other machinery. Threaded holes are what operators use to fasten specific components to the fixture plate.

Can You Use Threaded Holes for Mounting?

No. Although many clients assume otherwise, the holes in a threaded fixture plate should not be used for mounting, which is why Rayco offers mounting holes as a customization option. Using a threaded hole as a mounting hole will likely damage the threads, rendering the hole useless for securing components in the future.

Learn More About Threaded Holes & Mounting Holes

A fixture plate can make your processes more accurate, simple, and repeatable. If you need a fixture plate with mounting holes, or have questions about what thread type your fixture plate should have, contact Rayco today. We’ve been an industry-leading manufacturer of custom fixture plates and fixture components for more than four decades. Please fill out our online form today to request a consultation with one of our experts.