Step 4.4. Notching the muntin bars
I cut all the ¾" x ¾" (18mm x 18mm) cedar muntin bars to length.
42 pieces @ 21 5/8" (540mm) long and 24 pieces @ 59¼" (1480mm) long, enough to make 6 grids - two for each door and window unit.
The muntin bars needed to be notched (channelled out) at various intervals so that the notches in the vertical muntin bars would slot into the notches in the horizontal muntin bars and form a rectangular grid approximately 21 5/8" (540mm) x 59¼" (1480mm).
The notches needed to be the width of a muntin bar and 50% of the depth.
I lay groups of muntin bars side by side.
I marked where to cut the notches along the muntin bars.
The vertical muntin bars needed seven notches spread evenly along the length.
The horizontal muntin bars needed four notches spread evenly along the length.
I then set the blade on my circular power saw to a depth of 50% the thickness of a muntin bar.
I made multiple saw cuts along each of the marked areas and then cleaned the notches out with a sharp chisel.
By doing this I was able to notch out multiple muntin bars at one time.