Balsa Model Assembly Jig

thingiverse

The larger slotted one allows you to securely hold 3/32" thick balsa or plywood pieces in place for joining, ensuring they are aligned squarely every time. The second narrower slotted one is specifically designed for holding 1/16" thick pieces with precision. The tall fixtures also make it easy to align curved or slanted keels. Each slotted piece attaches firmly to the rail using a M4 Tee nut that threads smoothly into place. However, due to the quality of the threads, they may require chasing with a tap for optimal fitment. Fortunately, the slotted pieces on top can be used as is without any modifications needed. The assemblies are held together and in their designated position by an M4 x 12mm socket head cap screw that provides extra stability. Each leg assembly relies on either M4 x 8mm set screws or socket head cap screws to keep it firmly in place. To ensure accuracy, align the slot on the bottom of the fixtures with the protruding part of the Tee nut. This ensures that the pieces are properly aligned and securely attached. The slotted pieces attach directly to a 20x20mm section of 80/20 material; the longer the better for maximum stability. However, it's worth noting that the minimum distance between two parallel slots is 1" but can be reduced to 3/4" by simply nipping off the ends of the Tee nuts. If printed as shown, no additional support is required, making the process even more efficient and convenient. I personally use these fixtures for building model boats and planes, relying on them to keep ribs square to the keel while the glue dries securely in place.