Some Babicz Full Contact Hardware bridges, tremolos, and tailpieces include metal body inserts. These threaded body inserts are installed in a guitar or bass body, and are used to mount the bridge via the included mounting posts.
People often ask, what is the best drill bit size for installing these inserts? In our experience, there is no exact size to recommend for every installation project.
It all depends on the density of the guitar body wood. For example, Rock Maple, Mahogany, Basswood, Ash, and Pine are common body woods for guitar, and all have dramatically different densities and toughness. One drill bit size does not apply to all body woods.
To find the correct size we HIGHLY recommend measuring the diameter of the body inserts with a Caliper, or Micrometer, then performing a "test" hole in similar scrap wood to check the insert fit. The drill size should be slightly smaller than the diameter of the body insert, and should be tapped in with a plastic mallet with medium pressure. If installed correctly, gluing-in the inserts is unnecessary.