other glueable materials that have sufficient structural integrity without affecting the instrument 39 s weight and balance the neck block is of the dimensions so that it fits between the heel and the inner heel in a tight manner but still maintains enough looseness to allow for vertical movement of the neck via the neck height adjustment screw 13 in the embodiment displayed in fig2 u2013 4 there are additional securing screws 14 which provide further re enforcement of the neck to the guitar body the additional securing screws 14 pass through recesses in the neck block and into a threaded recess in the inner neck heel 16 for receiving the neck securing screws when the additional securing screws are tightened clamping pressure is created which re enforces the securement of the neck heel to the neck block the user can access the neck securing screws through the soundhole 17 and can make periodic adjustments to maintain proper tightness within the heel slot fig4 illustrates an embodiment of the adjustable neck assembly wherein the inner heel 20 has inserts 18 made out of a sturdy material such as metal that are secured in position the neck height adjustment screw insert 22 is embedded within the neck between the heel 9 and the inner heel 20 fig5 shows a top planar view of the neck pocket 30 and neck block 11 the neck block 11 contains guides 19 made out of metal or a plastic material such as polypropylene the guides 19 are shaped so that the neck heel inserts 18 fit securely within the guides the.