This student cello had developed a rib crack near the endpin. Although the traditional repair would involve removing the top, making custom inside and outside molds, and installing conventional cleats, that approach was difficult to justify for an instrument of this quality. Instead, I developed a simple repair that used an outside mold to align the crack, then installed a reinforcing cleat through the f-hole with the aid of wires, a custom clamping block, and a specially made cleat. The crack was glued, reinforced, and stabilized with minimal disassembly. The temporary positioning holes were then plugged, touched up, and blended into the original finish. The following photographs document the repair and the shop-made tools that made this approach possible. - Flatten the Crack: Use an outside mold to clamp the rib crack flat and bring the damaged area back into alignment.
- Drill the Rib: Drill two small holes through the rib for the clamping lines.
- Feed the Wires: Push two guide wires through the holes and out through the f-hole.
- Prepare the Clamping Block: Make a small internal clamping block with two holes and shallow grooves so the lines can lie flat.
- Tie the Lines: Secure the strong, flexible braided line to the clamping block with the knots recessed into the holes.
- Make the Cleat: Shape a small cleat with holes that match the spacing of the rib holes.
- Soak the Cleat: Soak the cleat in water so it becomes slightly more flexible.
- Prepare the Block: Apply Vaseline to the face of the clamping block so it will release easily after the glue cures.
- Thread the Cleat: Pull the two lines through the cleat and apply wood glue to the gluing surface.
- Skin the Glue: Use a heat gun to lightly skin the glue so it stays in place while the cleat is being installed.
- Attach the Guide Wires: Secure each line to the end of its guide wire with a very small amount of CA glue.
- Pull the Lines Through: Pull the wires back through the two rib holes, making sure the lines do not cross.
- Position the Cleat: The glued cleat is now inside the cello with two lines available to pull it securely against the rib.
- Set Up the Pulley: Position the center clamp so it acts as a pulley and keeps the pulling force straight.
- Prepare the Clamps: Use two additional clamps with small holes in their spindles and thread the lines through the holes.
- Tighten the Cleat: Run each line over the center pulley clamp and tighten it by turning the clamp spindle.
- Remove the Clamping Block: Allow the glue to cure overnight, remove the clamps, then pull the opposite ends of the lines to release the internal clamping block.
- Plug the Holes: Fit two small wooden dowels into the temporary holes in the rib.
- Finish the Repair: After the dowels have dried, trim them flush and apply touch-up varnish.
 IMG 20260810 114235 029 | IMG 20260810 114223 006 | IMG 20260811 095618 906 | IMG 20260812 094533 342 | IMG 20260812 094120 098 | IMG 20260811 182332 454 | IMG 20260811 182146 145 | IMG 20260812 160732 498 | |
Note: This was the first time I used a two-hole method for positioning the cleat. My earlier repairs used a single hole, but that allowed the cleat to rotate during installation. Correcting the alignment meant looking through the f-hole with a mirror and trying to reposition the cleat with a long tool before the glue began to set. Since the grain should run perpendicular to the crack for maximum strength, the second hole keeps the cleat properly aligned as it is pulled into position. |
