Those of us who have built boats know that boats are complex shapes and joining their various parts can be a tricky business. Back in 1981, I discovered a good way to make accurate fits in Roger Simpson’s article, “The Incredible Joggle Stick,” in WoodenBoat No. 39.
Simpson cut the device he called a joggle stick from 1/4″ plywood, giving one side a sawtooth edge with “teeth” about 2-1/2″ apart and the “gullets” numbered. To create a pattern for a cabin bulkhead that would fit the inside curve of the hull he’d built, he clamped a piece of plywood as a “tally board,” which would serve in a way similar to a spiling batten, to an overhead deckbeam. He pressed the joggle stick against it, positioned with its point in contact with the hull. He then traced both edges of the joggle stick on the tally board and wrote the number of the gullet at the corresponding spot on the tracing.
After tracing on the tally board as many locations as he required to define curves, straight lines, and corners, he set it on the plywood that would become the bulkhead. With the joggle stick positioned on the tally board in alignment with the tracings, he would make a pencil mark at its point. Connecting the dots plotted on the plywood provided the line he could cut to for a precise fit. Simpson noted the joggle stick was “fiendishly simple, revoltingly accurate, and beautifully fast.”
The method worked well for me, and I used it frequently for fitting thwarts and sternsheets. It was especially useful when working on thwarts that were notched to fit around sawn frames in dories. The multiple tracings and numbers on the tally board, even by Simpson’s own assessment, could get a bit confusing when a lot of them overlapped. I stopped tracing the straight side of the stick to eliminate some of the clutter. Later, I got frustrated tracing the sawtooth edge. Each facet required a separate stroke with the pencil, increasing the likelihood of the joggle stick slipping out of position.
I made new joggle sticks with one wavy edge. I could trace the edge with one quick pull of the pencil. Because the curves were cut freehand on the bandsaw, none of them were alike, so there was no need to number them. That made the “joggling” appreciably faster.
An article by Arch Davis in WoodenBoat No. 177, “Measuring Interior Joinery,” provided another variation on the patternmaking system with a straight-edged “tick stick.” Davis not only did away with tracing both sides, as I had, but also made the traced side straight. The edge had numbered marks, one of which was used to record the position of the stick with a pencil “tick” and the corresponding number next to the traced line.
I quickly traded my joggle sticks in for tick sticks. I preferred having some irregularity on the edge to register the stick without having to eyeball markings along a stick with a straight edge; a 1/2″ sanding drum on a Dremel tool made shallow grooves that would be traced along with the edge. Making a single groove, a pair of grooves, and a set of three grooves at intervals along the stick allowed me to use its full range on the tally board. And I can flip the stick over to change the side the point at the tip is on, and the little scallops on the traced line will indicate which way to place the stick.
Davis raised a good point about adding a block of wood under the tip of the tick stick if the reference surface secured in the boat is underneath the story board. Without it, a surface angled away from the story board would lead to an oversize piece and a poor fit. To meet angled surfaces, the new piece will need to have bevels cut. You can take the angles with a small bevel gauge using the tick stick to orient on leg of the gauge.
Even with these improvements, a tick stick, especially a long one, can easily slip when you’re drawing a pencil line along its edge, especially when the pencil is at a distance from the hand holding the stick. I added pegs along the edges of my story board. They not only help stabilize one end of the stick, but also organize the pencil lines as radii that don’t overlap. When the points recorded are being transferred to the piece to be cut, the peg holds one end of the tick stick in the proper position, so I only have to focus on the pencil line and the scalloped marks. Making fine adjustments there doesn’t move the end at the peg, speeding the process.
I have a tick stick 24″ long and another 17″ long, and it only takes a few minutes to make another if the space I’m making a pattern for requires it. Simpson’s original joggle stick was indeed “fiendishly simple, revoltingly accurate, and beautifully fast,” and I’d like to think he’d find the quick tick stick is even more so.
Christopher Cunningham is the Editor of Small Boats Magazine.
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