One Last Thing!
Suppose the higher mid-neck action created by greater neck relief DOES feel okay to you. What can you gain by keeping that same action, and reducing neck relief? 5th fret action will remain the same, but neck relief and 12th fret action (by default) are going to change.
Let’s see what the respective actions look like: (NOTE: the subscript "a" and "b" indicate a different set of data than previously given).
| Low E | Action | |
| Fret | R = .018" | R = .008b |
1 |
0.028 |
0.025 |
3 |
0.056 |
0.053 |
5 |
0.072 |
0.072 |
7 |
0.084 |
0.086 |
9 |
0.093 |
0.098 |
12 |
0.096 |
0.115 |
Your first reaction might be to compare 12th fret actions and say "Wow!! Look how high the second set is!". True, but look at the actions leading up to the equal 5th fret actions- they’re lower in the neck with less relief. Not much, but still measurable. And remember, with that higher 12th fret action, you get to run a taller saddle which can be a good thing (or might not be- a topic for further discussion! <g>). In any case, you can clearly see here that the 12th fret action is only a small part of the whole story. Let’s see what the next fret clearances look like:
| Low E | Next Fret | |
| Fret | R = .018" | R = .008b |
1 |
0.016 |
0.014 |
3 |
0.012 |
0.012 |
5 |
0.012 |
0.012 |
7 |
0.012 |
0.011 |
9 |
0.008 |
0.008 |
12 |
0.008 |
0.011 |
With the exception of the 1st fret, these clearances are pretty much the same. But remember, you get a lower action for the first 5 frets on the neck with less relief! Now, what about mid-way actions?
| Low E | Mid-way Action | |
| Fret | R = .018" | R = .008b |
1 |
0.076 |
0.082 |
3 |
0.066 |
0.098 |
5 |
0.064 |
0.094 |
7 |
0.060 |
0.084 |
9 |
||
12 |
||
The neck with less relief blows the other one away. When fingered at the 3rd fret, the guitar with less relief has a whopping .098" of clearance at the 12th fret, while the one with greater relief has only .066". That’s almost a .035" D string we’re talking about! Now which neck do you think would work better for a 1st position bluegrass player? The one with a higher feel, lower mid-way clearance, and equal next fret clearance? Or the one with a lower feel, far greater mid-way clearance, and equal next fret clearance?
Conclusions:
Given the same mid-neck action, less relief will produce a neck with lower 1st-5th fret action, greater mid-way action, and equal next-fret action, than a neck with the same mid-neck action, but greater neck relief. Once again, less relief wins.
Overall conclusion and subjective discussion:
To me, the evidence is clear. Less neck relief is the winner all the way around. It’s also clear that you cannot simply adjust neck relief- you must also pay attention or be aware of what’s happening to the nut and saddle actions. It seems to me that the common rules "Bluegrass players need neck relief" and "You need neck relief to bend strings" are a myth. The figures show clearly that, given the same action (at any fret), that less neck relief produces a lower feel and a higher action midway from any given note to the saddle.
Feelwise, I’m a big fan of flatter necks, which is what led me to do all these measurements. The lower mid-range action of a flatter neck makes a huge difference to playing comfort for me, and even when the 12th fret action is higher, the action gets consistently higher. This is not true of a neck with greater relief- with those, the action gets stiffer in the mid-neck and then softer as you hit the higher frets. I especially notice this on mandolins where far more of the playing is done in the mid-neck area. Some electric guitar players like more relief when bending in the mid-neck area, but given the data on next-fret and mid-way clearances, I think they'd be better off putting that same action into a neck with less relief.
Disagree? Have evidence to the contrary? Let me know- I don’t care if I’m right or not. I just want to setup the best playing and sounding guitars and mandolins possible.