Many electric guitar builders stress the need for a very tight-fitting neck/neck pocket. I find this the most difficult aspect of the build.

Question 1: if a neck is bolted (4 bolts) but is not a tight fit (say 0.5 mm - 1.0 mm gaps around the neck in the pocket) will this significantly lower the sustain from the overall instrument?

Question 2: if I fill these gaps with epoxy or glue+wood sandings (for looks, mostly) - will it make a difference? Many thanks

  • Good question. I thought about this myself on a JP strat that I have on the wall. The reason I love my LP collection is for the sustain they provide. But the strat is sooo easy to play, the neck is such a fit for me... Wonder if anybody answers with some experience on this.
    – blusician
    Oct 7, 2016 at 3:03
  • Can you clarify whether you are only concerned about sustain, or whether you are also asking about tone? In my experience, it's hard directly compare bolt on versus set neck designs because usually there are many other differences. At this time, the most direct comparison one can make is probably between the PRS Custom 24 (set neck) and the PRS CE24 bolt on, both made in Maryland. Oct 7, 2016 at 3:03
  • This reviewer said his CE24 has as much sustain as his Les Paul, but there's no comparison with a custom 24: forums.prsguitars.com/threads/ce-24-initial-impressions.18803 Oct 7, 2016 at 3:06
  • I've added a more in depth response below, but I don't personally understand the need or drive for sustain? Stratocasters lack sustain for a number of reasons; I personally hold the bridge design accountable, but no doubt there are other reasons. Are you talking purely about how long notes 'ring out' for once struck? If so I'm not convinced that this is superior in Les Pauls or other set-neck instruments because they are set-neck designs, purely because of the myriad other differences between the two designs. I think the attack and decay envelope is totally different between the two designs.
    – ABragg
    Oct 7, 2016 at 11:24
  • Many thanks for this input. Being largely deaf from too many years of music, all of this probably makes little real difference! However, to clarify, my concern about the tightness of the neck pocket was probably about tone, not sustain, and I thank you for the advice. I was also a bit concerned about the strength of the join. You'd think 4 bolts would hold tight, but I guess a close neck pocket would add strength, hence my idea abou filling the gaps.
    – Doug
    Oct 10, 2016 at 4:47

2 Answers 2


Having built various electric guitars and experimented with neck fixing, I have a pretty good viewpoint on this, achieved through testing and comparison.

For you, filling in the gaps will be almost irrelevant. The key linkage is that direct line between bridge and nut, through the wood between the bridge and the neck joint, the bolts that hold the neck tight against the body, and the wood of the neck.

Yes, for very high end guitars (way beyond my price/skill bracket) the shape of the surrounding wood has an effect on sustain/resonant frequencies, but it probably isn't going to be important at your level either.

High end luthiers would concern themselves with this, as would other high end woodworkers such as furniture makers, but for the purposes you describe, you can fill the gaps in without worrying about loss or improvement of sustain or tone.


Some luthiers demonstrate that their bolt-on necked guitars can hang together without the bolts being inserted. I think this more an attempt at showcasing/showboating carpentry skills than musical instrument building skills, personally. Conversely a lot of highly coveted pre-CBS-era Fender instruments have visible gaps either side of the neck, big enough to get a guitar pick, if not several, into.

Ultimately I think it is a matter of personal taste. You can cook up a legitimate-sounding pseudo-scientific reason for both a tight and a loose neck pocket. After all, a lot of guitarists and luthiers think nothing of inserting a folded up piece of sand paper or bus ticket into a neck pocket to 'shim' a neck. This instantly breaks the solid wood-to-wood joint being made in the neck pocket. Moreover I've seen numerous Fenders with that finish crack in the body around the heel of the neck, indicative that perhaps the geometry of the neck heel or neck pocket has altered over time and cracked the finish. Does then a loose neck pocket allow for wider variation in climate without the risk of harming the finish, or does a tight neck-to-body join provide a robust barrier to moisture ingress, preserving the structural integrity of the instrument overall? And what impact does this have on the perceived tone of the instrument? Will your audience notice?

The legendary tone-chasing guitarist Eric Johnson claims he can hear different battery manufacturers when he uses their products to power his fuzz pedals. He also angles his fuzz pedals carefully in or out of alignment with his other pedals as he feels this is also important to the tone of them. Finally he likes to remove the finish on the bodies of his Strats where the bridge is mounted, to provide a rawer bridge-to-wood coupling, again in the name of tone. Reckon you would find folded up bus tickets in the neck pockets in his Strats? Reckon he will have a strong opinion on shimming necks?

This is all, unfortunately, a matter of personal opinion, and the science just isn't there, either way. I wouldn't use epoxy or filler material as you never know when that neck might have to be removed! Consider using threaded inserts to get a solid neck-to-body join, but consider also that you need a drill press, this is a destructive modification, and you need to measure twice and drill once!

  • 1
    thank you so much for these comments. i am on guitar 4 and with better tools they are looking better. From all this kind advice, I think I will stop worrying about getting super- tight neck pockets! I followed the tone wood /sustain debates with great interest and have concluded that it's better to just get out and make guitars than worry about things that might make 0.5% difference!
    – Doug
    Oct 10, 2016 at 4:46

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