A loose divider is ready to go back into its groove, but now it stops short. It is tempting to sand the divider thinner until it slides home. Before changing the wood, look for the little ridge of dried glue that may be taking up the space.
Work with the parts already separated; do not pry apart a sound joint just to inspect it. Brush away loose debris and use a light held across the contact faces. Check the bottom and corners of the groove as well as the divider edge. A hard, shiny bead or raised patch is a clue, though clear glue can be difficult to see.
Support the part on a steady bench and remove accessible residue in small, controlled passes with a suitable hand scraper. Keep your fingers behind the cutting edge and wear eye protection. The aim is to lift the glue without digging into the groove walls or rounding over the mating edge. Stop if the tool starts tearing wood instead of removing the deposit.
Try the parts together gently after each small cleanup. Do not hammer the divider in or use clamps to force it home. If it still binds, check for swelling, a warped part or a damaged corner before taking off more material. A tight fit is a symptom, not proof that the whole divider is too thick.
For a repair that will be glued, follow the adhesive maker’s surface-preparation instructions. New glue over an old glue film is not the same as a clean wood-to-wood bond. Avoid soaking the joint or trying an unknown solvent to soften the residue; that can affect both the wood and nearby finish. If you cannot prepare the joint without damage, reconsider the repair rather than hiding the problem under more glue.
Practical takeaway: remove the obstruction before resizing the part. A careful look and a gentle test fit can save the sound wood you need for a snug repair.
Box RepairsWood GlueHandcraft Tips