Picture Frame Joinery: 4 Proven Methods for Strong Corners

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Building a picture frame consists of multiple steps: measuring, cutting, gluing, and clamping.

The corner joints are the hallmark of a well-made frame. We describe 4 methods of joining the corners are described below.

Tools for Making Picture Frames

  1. Table or miter saw with a 40-tooth or higher blade for clean cuts.
  2. Crosscut sled or miter gauge for exact 45-degree angles.
  3. Stop Block to ensure consistent length cuts for even corners.
  4. Quality glue like Titebond for a strong glue bond without deep absorption.
  5. For small frames, reliable masking tape can secure the joints, while a band clamp is ideal for larger frames to maintain tightness and ensure corners are square.

What Are Mitered Picture Corners?

45 Degree Cut

Mitered picture frame corners are where the frame’s edges are cut at a 45-degree angle and joined to form a 90-degree corner. This creates a clean, professional look without visible end grain.

Precision in cutting and joining is crucial for a seamless appearance.

How To Join Picture Frame Corners

Miter Joint

When it comes to making the mitered joint, though, there are several options for the actual joining.

None of them are particularly difficult, although some are easier than others, and some do require special tools.

Biscuits

An oval-shaped piece of beech or particle wood.  A slot is cut in each piece of wood (frame rail) using a biscuit jointer; the biscuit is covered with glue (or glue is put into each slot) and inserted into each slot connecting the two pieces of wood.

When the glue has had ample time to dry, the joint is secure.  If the frame is large and the rails have the available space, a brad or two (small nails) can also add extra strength to the joint.

Splines

A rectangular piece of wood that fits in grooves of each frame rail.  They, too, provide additional surface for gluing, just as biscuits do.  More work is involved with splines to join mitered corners, and the splines will be visible on the outside of the frame corner.  However, they are a viable option for creating a strong corner of your picture frame.

They help reinforce and align the edges.  Softwoods are not a good choice for splines; use a more dense wood like walnut or hard maple.

Pocket Screws

Pocket Hole Jig

Recessed holes are drilled in one frame rail using a special drill guide, and pocket hole screws (they fit in the recessed hole “pocket”) are used to join the two frame rails.  They require a little extra thought and planning, but they provide an extremely strong joint, making them a good choice for larger frames.

V-Nails

Commonly used in framing, including picture, window, and door frames.  They are like staples in a sense, actually v-shaped, spanning the seam and embedding in each end of the two frame rails being joined. 

V-nailers are used to deliver v-nails.  The business end of the v-nailer has a v-shaped “frame” with a 90-degree angle; the two frame rails are joined in that “frame” while the v-nailer embeds the v-nail across the seam and into each piece of wood.  For small frames, this is overkill, but it is an effective way to create solid joints for larger frames.

No matter which joining method you choose to connect and fasten the frame nails all around, glue is also a good choice.  Give it enough time to dry fully, and be sure to wipe off excess glue with a damp cloth before it dries.

Picture Frame Joinery Methods Compared

Joinery MethodProsCons
Biscuits
  • Provides additional gluing surface for strength.
  • Aligns pieces accurately.
  • Hidden from view once joined.
  • Requires precise cutting of slots.
  • Specialized tools needed (biscuit joiner).
Splines
  • Adds decorative element to the frame.
  • Strong joint due to increased surface area.
  • More complex to execute.
  • Visible on the outside of the frame, which may not be desired.
Pocket Screws
  • Strong and easy to adjust.
  • No need for advanced clamping methods.
  • Quick assembly.
  • Screw heads may be visible unless covered.
  • Requires a pocket hole jig.
V-Nails
  • Common in professional framing.
  • Provides a strong joint when used with a v-nailer.
  • Requires investment in a v-nailer tool.
  • Technique may take practice to perfect.

How Do You Clamp a Picture Frame Corner? 

Picture Frame Clamp

A 90-degree corner clamp (or strap clamp) will do the job for most any frames you are building in your home woodworking shop.  They are available in local hardware stores, large DIY stores, and online retail websites.  They are not expensive and come in various sizes to match your project needs.

They will provide a 90-degree angle with adjustable clamps for each piece of frame rail to be joined.  The rails will be held in place while you join them, exposing the corner for whichever means of joinery you have chosen.

For larger frame projects where a V-nailer is going to be used, the business end of the nailer will already have a 90-degree “v” that will align and hold two frame rails in place for the v-nail to be embedded.

Summary

A miter saw, a biscuit jointer, a 90-degree corner clamp, some wood glue, four biscuits, and maybe some brads for smaller frames, and you have all you need to create a frame for your painting, or your kids’ school photographs, or whatever else needs framing.

For larger projects, perhaps a pocket screw joinery or splines will be needed; and for even larger framing projects, a v-nailer and v-nails.

The basics are still the same, though a true and clean 45-degree cut, wood glue, and a joinery plan.  Before you know it, you’re hanging that frame on your wall after a job well done.

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