Secure the ribs and upper block of the violin to ensure they are securely glued to the back and top of the violin. This should already be the case, but sometimes the violin top becomes loose.
Make sure there are no nails or screws connecting the neck to the bottom from the inside. This is usually only the case with cheaper violins.
Saw the heel of the violin neck around the heel to the bottom of the neck. Make sure you saw the entire neck off.
Ensure that the heel of the neck doesn't connect to the button of the violin. If it is connected, you will tear off the top when you try to remove the neck.
Hold the violin against the bench and gently hit the top of the neck at the nut with a free hand until the neck comes loose.
Apply an 8- to 10-millimeter piece of wood onto the back of the heel. A thinner piece of wood will create a nominally brighter sound than a thicker piece of wood. The thickness on this part of the violin does not contribute majorly to the sound.
Glue the wood to the back of the heel using a small amount of wood glue. With the heel placed back in position, you can now trim any excess wood that peeks out from the sides of the neck with a fine razor.
Replace the neck on the instrument using glue or replacing the original screw that held the neck to the instrument.