PEM® PreMask™ Thread Masking Plugs
Thread protection - reducing labor and increasing production throughput
Samples are provided for evaluation as part of the PEM® early-adopter program.
- PEM® PreMask™ technology is the next generation of pre-masked plugs, eliminating the need for secondary masking while ensuring thread protection through finishing.
- PEM® PreMask™ nuts can be auto-fed and installed using standard Haeger® and PEMSERTER® machines, air tubes, anvils, and a standard flat-head punch (Haeger PN 15-02216).
- PEM® PreMask™ plugs can be removed four ways:
- Manual push-out with a blunt hand tool
- Manual pull-out using a dental pick
- Ejection on insertion of a dog-nose bolt, which pushes the mask out as it threads in (Note: Ejection with a fully threaded bolt is possible but results in “crumbing.”)
- Automated ejection on Haeger T-Series machines.
- PreMask™ parts are designed to endure harsh finishing environments with elevated bake temperatures, including powder coating at 250°C and above.
Frequently Asked Questions
Can the PEM® PreMask™ plug come in a color other than white?
No, the plug is only available in white.
Does processing affect the plug?
After baking, plugs yellow slightly and get a little harder or softer.
Can a fully threaded bolt eject the plugs?
Yes, but it grinds the plug into fragments, which you can clear with an air gun. A dog-nose bolt reduces this by pushing the plug out ahead of the threads.
Can I get PEM® PreMask™ on standoffs?
Not yet. We’re working on a related technology.
Can I get my specific part number with PEM® PreMask™?
Yes. Ask your PEM® account manager.
The plugs are collecting metal chips from my Haeger® bowls. Is that normal?
Yes. Without the plug, those chips and other foreign object debris (FOD) could end up in your clinch nuts.
Why does plug material sometimes stay in the threads?
Nut threads can cut off small pieces during ejection. Installing the bolt usually clears them (see photo), and they don’t affect torque values.
Any PEM® PreMask™ plug residue is less than a paint drip or bridge leaves, and much less than paint-cutting screws leave on over sprayed parts.
About 10% of PEM® PreMask™ plugs may tear slightly during ejection, depending on nut size, bake cycle, ejection tool, and force. Running a bolt through the threads usually clears any residue, and it’s much less than what paint, thread patches, bluecoat, or other masking methods leave behind.