Guitar brace jack
The method to deal with the loose volume is very simple, use glue between the sound beam and the wooden board, then put jack in, adjust the appropriate height, wipe out the excess glue that is squeezed out, and wait for the glue to dry.
It has an elastic screw nut, which can easily adjust the height. The height adjustment range is from 65mm to 128mm. There are grooves on the top and bottom of jack to fit the volume.