Internal Corners

Create clean, seamless 45-degree mitered corners with zero visible fittings on the outside. Engineered for building custom window and door screen frames, these hidden internal corner keys slide completely inside the hollow ends of 45-degree miter-cut screen frame profiles—delivering a sleek, professional finish without exposed plastic or metal joints.

Whether you are manufacturing new screen frames or repairing existing units, these corners lock frame rails tightly together at a perfect 90-degree angle, ensuring your screen stays square, rigid, and distortion-free under mesh tension.

Key Features & Benefits

• Concealed Internal Design: Slides fully inside the frame channel to create clean, continuous mitered joints with no visible corner hardware on the exterior.

• Precision 90° Alignment: Holds frame rails firmly square to prevent racking, sagging, or frame distortion during mesh and spline installation.

• Plastic or Metal Options: Choose High-Impact Plastic for lightweight, non-corrosive residential frames, or Heavy-Duty Stamped Metal for maximum strength and structural rigidity on large screen doors and patio frames.

• Bulk Pack Savings: Available in convenient packs of 25, 50, or 100 pieces to suit single DIY projects or ongoing commercial production runs.

Product Specifications

Selection Guide: Plastic vs. Metal Corners

• High-Impact Plastic Corners: Ideal for standard residential window screens. They are weather-resistant, won’t rust or corrode, and provide a snug friction fit inside aluminum frame profiles.

• Metal Corners: Recommended for oversized window screens, sliding screen doors, or high-wind areas. Metal keys provide superior joint strength and resist flexing under heavy screen tension (such as Pet Screen or Solar Screen).

Important Sizing Tip: Before ordering, measure the internal profile dimensions (height and width of the hollow opening) of your aluminum screen frame rail to ensure a snug, precise fit.

Simple Installation Steps

1. Cut Frame Rails: Miter-cut your aluminum screen frame rails at exact 45-degree angles.

2. Insert Corner Keys: Slide one leg of the internal corner key firmly into the hollow end of a frame rail until seated.

3. Assemble Frame: Press the adjoining miter-cut rail onto the exposed leg of the corner key to form a crisp 90-degree joint.

4. Lock & Roll: As you install your screen mesh and spline around the perimeter, spline tension helps lock the frame assembly securely in place.

Frequently Asked Questions

How many corner keys do I need per screen frame?

Each standard rectangular screen frame requires 4 corner keys (one for each corner). A 25-pack will build up to 6 complete screen frames with 1 spare.

Can I use these with square-cut (straight-cut) screen frame rails?

No. These internal corners are designed specifically for 45-degree miter-cut frame ends. For straight-cut (90-degree) frame rails, look for external square screen frame corners.