How to Build Your Own Crosscutting Jig for Small Parts

Cut a piece of ¾-inch thick Medium Density Fiberboard (MDF) for the base, or “bed” of the jig, 48 inches by 3 ½ inches. Cut two pieces of 1-by-2 lumber 48 inches long, and two 12 inches long. Cut one piece of 1-by-2 two inches long. Measure the width of the base of your circular saw, and cut ¼-inch hardboard 12 inches by the width of your saw's base plus three inches. Cut a second piece of ¼-inch hardboard 3 ½ inches by 12 inches.

Glue and nail the long 1-by-2s along the edges of the MDF bed piece, standing on one narrow edge, flush at the ends. Use wood glue along the narrow edge and 2-inch nails from a pin nail gun to make the attachment. Fit the two inch piece of 1-by-2 between these two 1-by-2 side rails at one end of the jig to box it in. Glue and nail it in place, on its narrow edge, flush with the end of the MDF. Nail through the side rails into the ends of the short piece.

Glue and staple the small piece of hardboard on top of the 1-by-2s to cover the top of this boxed-in end. Use glue on the top edges of the 1-by-2, and staple through the hardboard, with its edges flush with the end of the jig and the side rails. Glue and staple the 12-inch pieces of 1-by-2 along the 12-inch sides of the larger hardboard piece, with their 1 ½ inch faces against the hardboard for guide rails for the circular saw; this piece will be your saw fence.

Fit the saw fence on top of the jig with one 12-inch edge centered over the jig, and pressed against the open end of the small hardboard piece, covering the boxed end of the jig. Staple through the hardboard into the top edges of the 1-by-2 to fasten it in place. Drive one 1 1/14-inch drywall screw through each rail of the saw fence into the tops of the side rails of the jig bed to reinforce it.

Set the depth of the saw so that it will cut through the ¼-inch hardboard of the saw fence, the 1-by-2 side rails of the jig's bed and notch the MDF base by 1/8-inch. Position the saw between the two 1-by-2 guide rails, start the saw, then cut across the jig from side to side. Fit pieces into the jig, against the far side rail of the jig, with the boxed end to your right. Adjust the piece, so that the cut line matches up with the hard board edge on the right of the cut you made with the saw. Cut the piece as you cut the saw fence, pushing the saw through the slot. The small offcut piece will remain in the boxed end of the jig. Tip the jig to slide it out.