Take one of the longest outside pieces, and taking the mortise bar, push into the mortise hole on the piece.
Next, take the other long stretcher bar, pushing into the other mortise hole creating a H.
4. Now, put the half bar into the mortise hole in the middle, making sure to leave the wedge cut towards the outside of the stretcher frame.
The next step is to take the other outside stretcher piece, pushing it into the next available corners. Make sure you bear in mind to keep the mortise bar (half bar) lined up with the mortise hole.
Now use the mallet to tighten up the corners.
Flip the stretcher frame upside down.
Now repeat steps 4, 5, and 6 exactly to complete your four window stretcher frame.
