Home Skills Carpentry

Woodworking Jig For Complex Shapes

Updated: Jun. 12, 2019

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How it works

Photo 1: Position the plywood

Lay the tick stick across the scrap with the pointed end near the line that marks the front edge of the window seat. Trace a line onto the scrap along the side of the stick.

Make the tick marks

Make two perfectly aligned tick marks, one on the stick and one on the scrap. Label both tick marks “1.”

Photo 2: Mark the other corners

Place the point of the tick stick in each corner, and trace lines and number tick marks just as you did for the first line (Photo 1). When you’ve traced a line for each corner and both front edges of the seat, remove the scrap.

Photo 3: Transfer the marks

Clamp the scrap onto the workpiece flush with the edge of the workpiece. Lay the tick stick along each traced line, aligning the numbered tick marks. Each time you position the stick, make an “X” at the pointed end of the stick. When you’re done, you’ll have a pattern with each corner of the shape plotted. Then you just have to connect the X’s.

Every day, boat builders have to cut oddball shapes—ones that would give a typical carpenter fits. But boat builders know an old trick most carpenters don’t. This simple technique, called “tick sticking,” allows them to mark out even the most complex shapes quickly and accurately. In a nutshell, tick sticking is a way to plot the key points of an odd shape (usually corners) and transfer them onto a workpiece. Once the key points are marked, you just connect the dots to create a cutting pattern that perfectly matches the desired shape.

At first, tick sticking looks like an exercise for geometry majors. But follow this article and you’ll quickly see how this simple technique works. We used tick sticking here to fit a plywood window seat into a bay, but the same technique can be used to pattern any flat shape onto any material. You need only a few simple tools:

• A pencil. For accurate results, sharpen it and keep it sharp.
• A straightedge such as a framing square or metal yardstick.
• A scrap of plywood, drywall or cardboard. The scrap should be as large as possible but smaller than the shape you want to cut.
• A tick stick: any long, narrow piece of wood cut to a sharp point at one end. We made a fancy, two-piece tick stick by screwing a short, pointed piece of 1×4 to a long 1×4. The short 1×4 piece compensates for the thickness of the 3/4-in. plywood scrap and allows the point to sit flat on the workpiece, making marking easier (Photo 3).

Scribing paper templates

Detail A: Check for gaps

Use a straightedge to see if any part of the wall curves or has gaps that need to be scribed.

Detail B: Scribe the wall

Tape heavy paper in place and then scribe the shape of the wall on the paper.

Photo 4: Finish the outline

Connect the marks using a scribed paper template, or a straightedge where the wall was perfectly flat.

Photo 5: Install the piece

Set the workpiece in place and congratulate yourself on a job well done. Now go build a boat.

Before you connect the marks you plotted with the tick stick, hold a straightedge against each wall the workpiece will butt into (Detail A). Unless the walls are perfectly flat (few are), you’ll see gaps between the walls and the straightedge. If you connect the tick-stick marks using a straightedge, you’ll end up with the same gaps between the walls and the finished workpiece. That’s not a problem if you plan to install molding to cover the gaps. But if you need a perfect fit, make paper templates to match the contours of each wall section. Just tape a strip of heavy paper along the wall and use a compass to “scribe” the contour of the wall onto the paper (Detail B). Then cut along the scribed line with scissors and use the paper template to connect the tick-stick marks on the workpiece (Photo 4).

Required Tools for this Project

Have the necessary tools for this DIY project lined up before you start—you’ll save time and frustration.

• Circular saw
• Clamps
• Cordless drill
• Jigsaw
• Straightedge
• Tape measure

Required Materials for this Project

Avoid last-minute shopping trips by having all your materials ready ahead of time. Here’s a list.

• 1x4
• Plywood or cardboard
• Sharp pencils