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One of the more common experiences you encounter when taking apart speaker cabinets, or any wooden object (such as a guitar) is an oversized hole. This is caused by over tightening wood screws, or drilling too large of a hole for the screw to fit into. When this happens, you can tighten all you want, but the screw just spins in the hole and doesn't provide any support. In speaker cabinets, this can cause excessive buzzing on low notes, or in some cases, the cabinets can literally fall apart. I've also seen guitar pickups fall out into the strings while people perform, losing the small (and hard to find) mounting screws in the process. Tape will hold a pickup in place, but it doesn't look that great.
Repair technique
Its not hard to repair, but you need to make sure that you don't cause other problems as a result of your work. Typically, if the wood is not split where the hole is, you need only add a bit of wood to be glued into the hole to make it as good as it needs to be. The type of wood I prefer is a softwood such as Pine or Aspen. These woods compress when screws are put back into the holes and give you a good strong fit.
More serious damage - Splits
If the wood has split as a result of the wood screw, the wood must be re-glued at the place where the split occured before you do anything else. It probably split as a result of not having a pilot hole pre-drilled to allow the screw to dig into the wood. Hardwoods, such as Oak, Mahogany, Maple, Alder and Ash cannot accept a wood screw without pre-drilling a pilot hole slightly smaller than the screw threads. Even softer woods, such as Pine or Bass Wood will split if too large a diameter wood screw is used.To repair this, you will need to separate the wood where it split and glue it together - this can often be done by screwing the original wood screw into the hole, forcing the break to appear. Once you get the break open, you can force White or Carpenters Wood glue into the open joints. After doing so, remove the wood screw and allow the wood to close down onto the break. If possible, clamp this until the glue fully cures.
A split may have occurred because the wood was too hard to allow the wood screw to enter the wood. To avoid this, drill an appropriately sized pilot hole before attempting to use a wood screw with this repair. To choose the right size drill bit hold the screw up to the light and then place the drill bits over the screw (lengthwise) - when you can still see the threads on the screw and the drill bit is covering the rest of the screws area, you have a pretty good fit - the threads need to 'bite' into the wood in order for it to hold.
Fixing the stripped out hole - No Splits in the wood
I frequently use common Toothpicks to make this sort of repair. You can get these almost anywhere and typically are made out of woods that are moderately soft. In the U.S.A. many are made of Aspen or Pine. If you plan to do the same, use the ones that are not painted. Sometimes you may want to use 2 or more Toothpicks. Don't use too many, otherwise you run the risk of splitting the wood (as discussed above). The next series of 4 pictures shows the process.
You can use any small narrow, long piece of wood to do the repair - I often use a pocket knife to remove a small sliver of wood from my scrap wood pile. Most often cutting a 1/8 inch (1.5mm) wide piece to use when filling the hole.
Always use White Glue or Carpenters Wood Glue to hold the pieces in with, Its a simple task to dip the ends in the glue before sliding the the Toothpick or wood slivers in place. DO NOT USE EPOXY or any glue that will stick to the wood screws - otherwise you may never be able to take the assembly apart again.
After Inserting the Toothpicks or wood slivers into the hole, I usually reassemble the unit and put the screws in - the wood screws will force the Toothpicks or wood slivers into the sides and make the newly added wood exceptionally strong. White glue and Carpenters Wood glue doesn't stick very strongly to metal screws, so you should be able to get things apart again when you need to in the future.
Repairing a stripped screw on a Guitar
This pick guard screw was stripped out on my Gibson SG.
- Step 1: Remove screw and find wood sliver for repair
- Step 2: Apply glue to sliver
- Step 3: Insert sliver into hole
- Step 4: Break off sliver
- Step 5: Replace screw
Questions? Comments? .
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