How to Make a Steel Lattice Jig

Lay Out the Lattice Panel Jig Design

• 1

  Lay a piece of 4-by-8-foot plywood on a work surface. Put a mark on the top edge and one on the left edge, each 12 inches from the upper left corner of the panel. Use a straightedge and draw a line connecting these marks, producing the first course control line. It will intersect the top edge and left edge at a 45-degree angle. The first course of metal jig strips (jig members) will all be placed parallel to this line. Note: This line cannot be near the corner, because the short line could result in a loss of precision lower in the design.

• 2

  Draw a line from the upper left corner of the panel perpendicular to the first course control line. Use a framing square to ensure that it meets the first course control line at a right angle. This is the second course control line. All second course lath will be placed parallel to this line and automatically perpendicular to the first course lath.

• 3

  Put on goggles and hearing protection. Measure 6 pieces of 1/8-inch-by-2-inch steel bar stock 8 feet long using a tape measure and framing square. Cut them square with a heavy reciprocating saw. File off all cut edges with a steel file.

• 4

  Use the tape measure and mark six spots -- every 8 inches -- down both sides of the 4-foot sides of the plywood sheet. Snap a chalk line to produce six horizontal lines between these marks. Use construction glue to temporarily attach the six pieces of steel to the plywood sheet. Set each piece of steel on the top of the horizontal line and use spring clamps to hold them in place. Allow the glue to set for 1 hour.

• 5

  Hold a piece of the steel on the first course control line. Extend the steel and allow it to extend over the upper plywood edge. Reach over and mark the steel at a point several inches beyond the left edge. Cut the steel with the reciprocating saw. Lay it against the first course control line and hold it in place with spring clamps. Use a scrap piece of lath as a spacer and lay enough over-length steel strips -- on both sides of the first one -- to fill out the plywood surface. These are the jig members.

• 6

  Mark the center point where all the jig members intersect with the strips below. Put a small punch hole in these marks and use a power drill and 1/8-inch bit to drill a single hole through both top and bottom jig members. Use a driver-blade attachment on the power drill and screw 1/4-inch machine screws through the holes connecting the jig members to the parallel members below. Invert the plywood on a work surface or floor and mark the lines where the jig members extend beyond the plywood. Place the plywood on a work surface and use the reciprocating saw to cut off the excess steel extensions. Do not remove the jig from the plywood at this point. This completes the jig structure.

Install the Diagonal Jig Screws

• 7

  Place the plywood right-side up on a work surface. Trace the second course control line -- from the original line drawn on the plywood -- onto the jig members. Hold a piece of lath on that line and draw a line on the jig members. Do this on both sides of the lath. This defines the second course lath position. Use a piece of steel and alternate with a piece of lath until all the parallel second course lines are drawn across the jig members.

• 8

  Punch and drill an 1/8-inch hole in the center point of all the lines on all jig members. Drive 1/8-by-1-inch machine screws into all the holes leaving 3/4 inch above the hole. Carefully pull the jig from the plywood and use household cleaner to remove the glue from its backside. The jig is now complete.

• 9

  Test the jig by laying strips of lath between the jig members and allow them to overlap the edges. Lay the diagonal lath strips between the screws that define the narrow widths, not the wider ones. When completed there should be overlapping lath in all the lath slots. Use a light-duty stapler and drive two staples into the intersection point of all lath. Invert the jig on a work surface and use a circular saw to cut off all the excess lath. This simultaneously miters all the edges of the lattice. Carefully pry the lath from the jig.