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Assembling knock down frames

Written by Rob | Mar 16, 2025 4:28:54 PM

Introduction

A three-piece knock-down (KD) hollow metal door frame is a popular choice for commercial and industrial buildings. It is shipped in separate pieces—two vertical jambs and one horizontal head—and is designed for easy assembly on-site. This guide walks you through the process of assembling and installing a KD hollow metal frame for a smooth and professional result.

Tools and Materials Needed

Before starting, gather the following tools and materials:

Tools:

  • Tape measure
  • Level
  • Rubber mallet
  • Drill (if needed for anchoring)
  • Phillips screwdriver
  • Shims
  • C-clamps (optional)

Materials:

  • Three-piece knock-down hollow metal door frame
  • Anchors (if required for your wall type)
  • Wood blocking (if required for installation)

Step 1: Unpack and Inspect the Frame

  1. Carefully remove the frame pieces from the packaging.
  2. Inspect all components for damage or defects.
  3. Check that you have all the required parts, including:
    • Two vertical jambs
    • One horizontal head
    • Compression anchors (if applicable)

Step 2: Assemble the Frame

A. Connect the Head to the Jambs

  1. Lay the head section on a flat surface.
  2. Identify the slots and tabs on the ends of the head section.
  3. Align the top of each jamb with the corresponding tabs on the head.
  4. Carefully insert the tabs of the head into the slots on each jamb.
  5. Use a rubber mallet to gently tap the joints together if needed.

💡 Tip: Some frames include screws for additional stability—tighten them after assembling the frame.

B. Secure the Frame Joints

  1. Ensure the jambs and head are fully engaged and aligned.
  2. If your frame has corner clips or brackets, secure them in place.
  3. Double-check that the frame is square by measuring diagonally from corner to corner.

Step 3: Position the Frame in the Rough Opening

  1. Place the frame into the rough opening of the doorway.
  2. Use a level to check that the jambs are perfectly vertical (plumb).
  3. Adjust the positioning as needed using shims.
  4. Temporarily hold the frame in place using C-clamps or by loosely securing it with anchors.

Step 4: Secure the Frame

  1. Install the compression anchors (if required) to secure the frame to the wall.
  2. Use the pre-drilled holes on the frame for anchoring.
  3. For drywall installations, use steel stud anchors or expansion bolts.
  4. For masonry walls, use masonry anchors or Tapcon screws.
  5. Check for proper alignment as you tighten the fasteners.

💡 Tip: Avoid overtightening to prevent the frame from warping.

Step 5: Final Adjustments and Finishing

  1. Recheck the frame for squareness and plumb alignment.
  2. Adjust shims or anchors if necessary.
  3. Tap any joints lightly with a rubber mallet to ensure a snug fit.
  4. Clean off any debris or dust.
  5. If required, apply caulk or filler around the frame for a clean finish.

Conclusion

Your three-piece knock-down hollow metal door frame is now fully assembled and ready for a door installation! Proper alignment and secure anchoring are key to ensuring a durable and functional installation. Following this guide will help achieve a professional, long-lasting result.

💬 Have you installed a KD metal frame before? Share your experience or ask questions in the comments below!