Using a radial-arm saw and a simple jig
Issue 83: March/April 2012
Sometimes, the lumber you have (or can obtain) isn’t long enough for the job you want to do. When building a wooden boat, for example, and you want the chine logs and stringers to be continuous, you have to scarf two or more pieces together to get the length you need. You can scarf lumber up to 3 inches wide easily and accurately on a radial-arm saw with the help of a simple jig.
To make the jig, start with a piece of 3⁄4-inch plywood that’s approximately 18 inches square or larger. The panel should be large enough to accommodate a fairly long fence that could also be of 3⁄4-inch plywood.
To achieve the typical 8 to 1 scarf ratio, measure 8 inches along one side, then 1 inch in. Connect this point to the corner and draw the diagonal (the dashed line on the diagram above). Cut along this diagonal to make the base for the scarfing jig.
Nail and glue a 2 1⁄2 – to 3-inch-high fence to the angled side of the jig base. Make sure the fence is square to the saw table or the scarfed pieces will have a gap along one side when fitted together.
Position the jig on the saw table, aligning the fence next to the saw blade, and clamp the lumber you want to cut to the fence. Use a sharp combination blade or any other blade suitable for ripping. (The saw blade shown in the photo is a 60-tooth fine-cut blade and not what I used in the end to cut the scarf.)
Advance the saw very slowly to avoid forward surge that tends to alter the alignment of the cut.
Gordon Otto fell in love with sailboats at an early age. He began building and repairing boats in his yard while in high school in Texas. Years later, while earning a doctorate at NC State, he built several Sabots and two 11-foot catboats from an old issue of How to Build 20 Boats. Now retired in South Carolina, he is building a 15-foot California Pelican.
Thank you to Sailrite Enterprises, Inc., for providing free access to back issues of Good Old Boat through intellectual property rights. Sailrite.com
