Set NEck is the one which is directly glued to the Body of the Guitar where as bolt on neck is the one which is fixed to the body of the guitar using screws and nut bolts. Set neck contributes to the Crunchy tone. Bolt on to certain extent doesnt. Fender Strats have Set Neck.
Well set necks are bad according to some luthiers because the only thing holding the neck to the body is glue. The sustain is one step ahead of bolt-ons although set necks are very comfortable. Another type is neck thru where the two pieces of the body are stuck onto either side of the neck like wings. This is also quite good but most conventional is bolt on. I prefer neck thrus because of the comfort level.
Check these out 1. Set Neck: https://www.zen-pharaohs.com/guitars/Fender/Merle/images/Mh_neck2.jpg https://www.chiptodd.com/images/Set Neck Gen1.jpg 2. Bolt on Neck https://content.answers.com/main/content/wp/en-commons/thumb/b/b0/180px-Bolt-on_superstrat.jpg https://upload.wikimedia.org/wikipedia/commons/thumb/c/c1/Bolt_on_neck.jpg/450px-Bolt_on_neck.jpg
Hardly conventional. It's the cheapest, hence the most common. Conventionally, guitars have had their necks glued in. The glue is so strong that if you try to break the neck, the wodd will split but the glued joint will not crack.
