How Much Relief Is Too Much?

[j. pierce]

I never payed much attention to setup until I started building my own guitars. On all my builds, I've been playing with lower action and less fret buzz than I ever did on a store-bought guitar or bass. I'm sure now that I could dial in one of my old guitars to the specs I play at now, but well, I don't have them anymore!

So on my guitars and basses to date, with the carbon fibre or graphite rods in the neck, I've never barely had to touch the rod if at all, and dial my necks in perfectly flat, or just until there's a slightly perceptable relief - I don't remember what feeler gauge could squeak in there when measuring, but there appears to be no relief visually using a slotted rule and the board, or using the strings and the fret tops. Capo at the first and last fret and push down in the middle, and you can just feel that there's a bit of relief.

Anyway, the 35" scale five-string bass I'm working on for my brother; it's got quite some relief in the neck. I did a quick fret level before stringing it up the second time, and with the action set medium low, there's annoying buzz in the upper register. I think I actually made it worse with my levelling job - it was done with the neck set perfectly flat, and the strings are adding relief. Or perhaps I was having an off day and just did the absolute worst fret job ever. (There's a reason I won't do fret work on anyone elses instruments!)

It's got a dual-action LMI rod in it. It's certainly making a difference, but I don't want to torque it dow any more, I'd say it's at it's limit. There was a little creaky noise when made that last bit of turn.

Thing is, I've never had to adjust a rod to where I thought the limit was, so that's got me a little annoyed, I guess this neck isn't as rock solid as I would have liked. So I need to dig out my feeler gauges and take a proper measurement; which I'll do tomorrow, but using a notched straightedge and the board, or a the strings and the frets, I'm reading almost a 1/16th inch of relief. Granted, this is eyeballing it with a not great ruler, so I could be a bit off, but it's visually more than I'm used to dealing with.

I'm feeling like this is cause for concern.

I can raise the action at the bridge and eliminate the buzzing, but then I'm raising the action higher than I'd like. (Although I'm getting the feeling that the low B is rubbery enough I'm going to want it a little higher than I'm used to with a low E.)

Plays like a dream on the low B and E, and the other strings up to around the 12th-15th, depending on how the action is set. I've got a piece of heavy duty angle steel (old rack mounting brackets) about 8 inches long (although I could make a longer one) that I lapped flat on the same piece of lapped stone I use for my plane soles - I'm thinking of trying to sue this to level the frets in the upper register under string tension as I've heard discussed; but I wonder if this neck is in too bad a shape and I need to think about re-leveling the board and refretting, taking into consideration what string tension will do to this neck, or perhaps start with a new neck.

So I guess long story short - how much relief do you let happen in a neck before you start to be concerned? And how far would you turn a truss rod from dead center?

[Southpa]

The MOST IMPORTANT part of doing setup work is your assessment. You can look at individual frets and then you look at the overall layout of the fb, neck, bridge etc. I can usually rule out a few factors by simply laying a straightedge along the fb, checking where the deepest relief should be occurring (mid truss rod of course) and sliding the straightedge towards the bridge to check the neck angle. When do you start messing with fret levelling and dressing? I remove the strings and relax the truss rod. Theoretically and ideally, the board should be flat. I also check for gaps and pinch points (rocking the edge) that indicates uneven frets for whatever reason (worn, loose, etc.) There is nothing wrong with doing a levelling/dressing so long as you have plenty of fret "meat' left and its done in a competent manner. Even if its not nceessary, its good practice anyway!

In another thread on this board there are some utube examples of some guys doing things to various guitars. I guess they can make things work but I don't recommend learning from those sources. Simply adjusting the truss rod and then looking down the neck to assess relief is not good enough for me. I need something a little more tangible than my own "eyeballing". However, I DO like to see what effect turning a truss rod has on my neck. So the good 'ol straightedge tells me all.

To answer your question, relief is where you find it and where you like it. I have done LOTS of work on guitars owned by friends and acquaintances and I usually ask them how they like their relief. They generally, reply with "HUH??!" People who like to hit the strings hard need more relief for that big amplitude they are generating. People who press hard might like low relief to avoid "sharp" notes. Fret height plays a role in this as well. People who play with a light touch (both hands) like low relief, a few guys on this board have mentioned that they prefer flat boards.

If you've done a levelling and dressing already and things are not right then you should be questioning your methods of assessment and interpretation of your results. You mention the low B and E play fine throughout the register which indicates something is uneven or maybe twisted? How many turns of the trussrod have you got in so far from slack position? If needed you could shoot a little bit of WD-40 to coax a little more.

Edited January 18, 2009 by Southpa

[j. pierce]

When I was "eyeballing" it, I was using a notched edge to read the board, or the strings (capoed at first fret, and fretting at last) to read the frets, and measuring my relief with a small ruler, rather than using feeler gauges underneath.

My "quicky" fret leveling the other day was mostly to identify any frets that were substantial problems - I find adjusting the board flat, marking the frets and making a few swipes of leveling, I can identify problem fret areas pretty quick. I didn't find any of these.

Obviously I should have taken more measurements before touching the frets - I've gotten complacent on my scratch builds, confident that neck will end up flat under tension and leveling the frets under that assumption before I string it up or check for fret problems that need to be addressed first. That was obviously my first problem.

My leveling methods appear to work well in all my other builds - a flat stew mac leveling bar and 320 paper.

The neck did pull into a slight twist - when it measures flat with no strings, the relief under tension measures slightly more (about .015" inches tops) on the treble side. This appears to be because so much more fretboard is supported by the heel and body join on the bass side.

Anyway - I think the major issue here was the trussrod and an unruly neck. I usually back of string tension, and try and manually flex the neck in the direction I plan on adjusting the rod - using the rod to hold the neck in place, rather than moving it. The long scale bass neck was a bit awkward to do this to. I followed a method in one of my stewmac books, of putting a notched block over the strings and fretboard at either end of the rod, running a heavy beam across those, and clamping the neck with a tiny bit of pressure to pull it in place. (Didn't take much at all.) Then I could tighten up the truss rod a hair (it's less than a quarter turn from the "neutral" position) and it seems to be holding the neck well, with relief around .02" or so. Still more than I'd like, but workable.

I'll play with it some more tomorrow before I touch anything else.

(Edit - entered a few numbers wrong from my notes)

[Southpa]

Well, you seem to have the right approach, trying to be systematic and thorough can be tough. Not all necks are alike and you might have a real "individual". Twist can also result in a non-Q-sawn neck when under string tension, especially long ones. With the strings off everything could be straight as a die, just add a little pressure and she could turn into a dog's hind leg. depends on the species, density, straightness of grain and cut.

[bluesy]

Anyway, the 35" scale five-string bass I'm working on for my brother; it's got quite some relief in the neck. I did a quick fret level before stringing it up the second time, and with the action set medium low, there's annoying buzz in the upper register.

That's exactly the problem I was talking about in a recent thread of mine about a method of optimising the setup for low action, while avoiding the problem you describe. The buzz in the upper register, for me, was caused by setting the action while the neck had too much relief. The upper register does not have much, or any, relief, because the neck is thicker and/or bolted to the body. Hence, you have no choice but to set the bridge high enough to avoid the buzzing. To get the action back down, you need to get rid of the excess relief. I haven't adjusted many basses, so I'll let someone else advise on how much you can/should torque the truss rod on yours.