End Block — Lutherie Encyclopedia

End BlockType: glossaryA solid block of wood glued inside the body at the tail end, joining the two sides and anchoring the endpin.## Definition The end block is a solid block of wood, usually mahogany, basswood, or Spanish cedar, glued to the interior of the guitar body at the tail (bottom) end. It serves as the structural junction where the two sides of the instrument meet and are joined together. The end block provides a strong anchor point for the endpin or strap button and, in many acoustic-electric instruments, for the output jack. It must be robust enough to withstand the stress of a strap supporting the full weight of the instrument. Typical end blocks are roughly 20mm to 30mm thick and shaped to conform to the curvature of the sides. The block is glued to the sides, the top, and the back, creating a strong multi-surface bond at this critical junction. ## In Practice During construction, the end block is one of the first internal components installed, usually glued to the side assembly in the mold before the top and back are attached. Builders must ensure the block is squared to the centerline and that its surfaces are shaped to match the contours of the sides precisely. When drilling for the endpin, the luthier must be careful to center the hole and avoid splitting the block. In repair situations, loose end blocks are a common issue, especially on older instruments that have experienced humidity extremes. A loose end block can cause buzzing, structural weakness, and visible separation at the tail seam. Regluing typically requires reaching through the sound hole with specialized clamps.