Checking relief, neck straightness and string arcs

[zuma]

I hope this is a simple question. I have setup my own basses for a long time and I have read most of the guides in the sticky post.

Long story short, I want to know this: When checking relief (capo at 1st fret, pressing down string down where neck meets the body, checking around 6th fret or so) should the measurement between the string and fret be the same when checking at the G string as well as, let's say, a low B?

Would the low B create a greater arc than a high G just sitting there, unplucked? The end game in my thought process is that I suspect I might have a slight hump on my G string side. I am TERRIBLE at sighting a neck so I thought that maybe I could measure the twist. I am tempted to buy that notched ruler from Stewart Mac but that's a lot of money for a ruler I may not need much.

[JustDavid]

The purpose of caop'ing & fretting at the last is to have the string act as a straight edge. Hence you should have no difference between strings, uneven fret wear or kinked strings aside.

I use a set of feeler gauges to measure neck relief. But for what you want to do anything fairly solid would work as all you want to know is if you have equal spacing.

[chadhargis]

I read somewhere that a good "baseline" setting is to set the strings to the thickness of a credit card. That seems to work well for me.

[walterw]

you should check both outside strings. the first one that gets too low, to where the frets actually touch, is where you have to stop straightening the rod.

ideally, they should have the same relief, or even show more relief on the bigger string. either way, neither one should show any backbow.

[zuma]

Originally Posted by walterw

ideally, they should have the same relief, or even show more relief on the bigger string. either way, neither one should show any backbow.

This is the heart of the matter. Why, if so, would the larger string show greater relief? If BOTH strings are a straightedge measured from the BOTTOM of the string to the fret then what would cause a larger string to have more relief? What do most of you see when you measure your basses?

[walterw]

Originally Posted by zuma

This is the heart of the matter. Why, if so, would the larger string show greater relief?

it's not a matter of "would", but of "should".

some makers actually level their necks to deliberately allow a bit more clearance under the big strings, because they vibrate over a wider area (plek machines are good for this).

others shoot for the same flatness on both sides (that's what i do when i level frets).

more clearance on the treble side indicates a slight twist in the neck, not a good thing.

[zuma]

Originally Posted by walterw

more clearance on the treble side indicates a slight twist in the neck, not a good thing.

I have LESS clearance on the G string than my B string so I guess that from a practical standpoint it is the way it should be as you describe.

This begs the question - What do most of you here check when you state your relief, your thin strings or your thick strings? I would assume the thin string.

[JustDavid]

I check the top string (B or E). Why? It's easier for me to check when in playing position.

[zuma]

So, 1 for the E string...interesting...I just realized my original question wasn't really answered.

Let's make this theoretical. Assuming a fingerboard has been made completely flat, would a relief measurement be the same on both sides of the neck?

[mongo2]

To me mismatched relief across the fingerboard board would indicate either a twisted neck, fret level issues, or a fingerboard that's asymmetrical with a swale or hump.

[zuma]

Alright then, here is what I'm going to do. I'm going to buy a fresh set of feeler gauges (lost mine) and measure several of my basses. I will post the results soon. I don't believe any of my basses (except my Jazz ) actually does have a twist in the neck so the results should be interesting.

It would be great if anybody else posted their measurements too! It doesn't really matter what the relief is...just looking to see if they are the same from skinny string to fat string side.

[Boot Soul]

A slight difference in relief on a bass that has had its frets dressed and polished straight will exist because the tension on the D and G strings is higher than the tension on the E and A strings. This will cause a slightly greater relief on the G string edge than On the E string edge of the fingerboard, which is just the opposite of what is ideal. So this may be compensated for by dressing the frets different from side to side (how this is done I don't know). On multi-multi string basses (6 or more) the difference in tension from one edge of the neck to the other is so great, that two truss rods are installed so that relief can be made slightly different side to side.

There is an excellent and interesting bass set-up guide that has been recently published by Jerzy Drozd and is available for free as a download. In this guide, everything that we are talking about here in this thread is discussed in great detail, and explained clearly.

Download requires registering for a free e-newsletter.....see:

http://www.jerzydrozdbasses.com/ulti...ass-setup.html

One other thing that should be mentioned is that for bolt-on neck basses like Fenders, it is better to evaluate relief by fretting at the first and the 17th fret (as is recommended in the Fender set-up guide), instead of all the way to the end on the 20th or 21st fret. This is because there is often a slight hump involving the last few frets that develops over the years. If you fret the string at the very end, this hump will make it appear that the neck has more relief than it does. There can even be a backbow in the neck between the first and tenth (or so) frets while over the entire length of the neck there may still be relief. This is one of the main causes of "S" curves in Fender and similar necks......these necks have had their truss rods over tightened to compensate for relief that was created by the hump at the end of the bolt-on area.

[zuma]

Thanks Boot Soul. I did grab that Jerzy PDF from the sticky in this forum. I tried to grab the latest but the newsletter sign-up seemed to be malfunctioning. Any how, even in that guide it doesn't mention which side is typically measured.

If what you're saying is typical then I am wondering about my neck now as the G side has less relief than the B side (5 string of course). If the skinnier strings pull the neck more then I should have more relief on that side according to what you're saying. Hmmm...this is getting interesting.

I am with you on measuring from the capo'd first fret and where the neck meets the body. Seems to make sense. Gotta love those ski ramps!

[Boot Soul]

Originally Posted by zuma

Any how, even in that guide it doesn't mention which side is typically measured.

I'm not sure about the version of this guide from the sticky, but the direct download that I have includes a section on how to adjust both of the truss rods, where the specific question you asked in starting this thread is completely explained.

In version 1.0 of the guide on page 42 and 43 look at the discussion on how to adjust the Diagonal Double Truss-Rod System. This is where the issue of differing string tensions causing a different amount of neck relief from edge to edge is discussed. This is a much bigger concern on these multi-multi string basses than it is on a 4 string.

All you can really do in a single truss-rod bass to correct this problem (if it is a problem) would be to level and dress the frets again and ask the luthier/tech to compensate for the effect in how the frets are dressed. I have no idea how this is done.

[zuma]

Ok, I have the same version of that PDF and I just read it again.

According to Jerzy (and as you pointed out):

When we're talking about basses with 4, 5 or even 6 strings, this difference in arc isn't very
big and a truss-rod located along the central axis of the neck is sufficient.

What is a ball park figure for isn't very big? This logic, which is new to me, would suggest that given a 4 string bass tuned to standard pitch using a single truss rod, our G string relief will be slightly more than our E string side relief.

It will be most interesting to see where my basses stack up. If I can find a reasonable average in the difference from one side to the other I think it would be pretty useful in diagnosing a possible twist in the neck.

This is assuming, of course, that all of my basses have a fretboard (or fretwork) that wasn't "compensated" side to side as others have pointed out. I'll admit I've never heard of those compensations but perhaps that's part of the secret to basses with amazing action/playability. However, maybe that's not something you would bother to do on a 4 or 5 string bass.

[mongo2]

Originally Posted by zuma

What is a ball park figure for isn't very big? This logic, which is new to me, would suggest that given a 4 string bass tuned to standard pitch using a single truss rod, our G string relief will be slightly more than our E string side relief.

A smidge isn't going to hurt anything but it could indicate an issue in waiting.

[John Wentzien]

For the price of a professional "straight edge" from Stew Mac..you could probably pay for a good PRO fret-level job..
Do this once, then the slight adjustment can be done at home to your own taste.

You'll probably be able to get by with a lot straighter neck than you think with a good level job.

[zuma]

Ok, I have my feeler gauges now. It took me some time to get the hang of using them but I believe my measurements are pretty accurate.

Capo at 1st fret, holding down 18th fret and measuring at the 7th fret I have:

.016 relief at the G string
.022 relief at the B string

That's a .006 difference. Incidentally, I have discovered that I would like to drop my relief to .012 on the G side and see how it goes. Any how...I have to do some work now but I am anxious to measure the rest of my arsenal. To be continued...

Oh, one more thing, I suppose that if your frets are worn unevenly, this could also cause an imbalance in relief measurement. Without resorting to a fancy Stew Mac caliper I believe mine are pretty even.

[loganbouchard]

it shouldn't really matter too much which side you use to check relief. i use the bass side because it's (as mentioned before) easier to do from sitting position. also, i use the bass side more than the treble side, so it's more important for me to make sure i adjust the neck accordingly. also, the lowest string vibrates the most, so it's the one i would really worry about in terms of allowing just the right amount of relief. (because the three higher strings don't wave quite as much when being plucked, they, ideally, have less liability for fret buzz.)

when i played 6 string, with two truss rods, i looked at both sides equally. (because either way, if you have to adjust the truss rod, you'd have adjust the two together.)

[zuma]

Okay, now I think I am getting somewhere. Here are the latest specs:

(Capo on 1st fret for all basses)

Bossa OB-5 5 string
right finger on 18th fret, measuring at 7th fret
.016 relief on G string side
.022 relief on B string side

MusicMan Bongo 4 string
right finger on 18th fret, measuring at 7th fret
.007 relief on G string side
.007 relief on E string side

MusicMan Stingray (1983)
right finger on 16th fret, measuring at 6th fret
.007 relief on G string side
.007 relief on E string side

----

I am really surprised at how low my MusicMan basses are set. They were both set up recently by the same tech so that would explain the consistency. Damn, they're low! I have no issues with them this low and I dig in pretty good, too. Cool! The '83 Stingray plays great but could use a fret dress. The Bongo is pretty much the smoothster of the bunch. No issues whatsoever, a fantastic bass.

Surprisingly, even with the uneven relief settings, the Bossa plays just fine. The strange thing is that when I switched out the strings it came with to DR Sunbeams, I started having issues with buzzing on frets 2 to 6 on the D and G strings. That's what started this whole thing! Nothing I did to the setup seemed to help. Frustrated, I removed the Sunbeams, let the bass sit for a week and switched back to the unknown strings it came with. No more buzzing! Hmmm...I'm still a little stumped with the Bossa but at least I feel like I understand relief a whole lot better than before. I'll try the Sunbeams again later I suppose.

As John Wentzien said, a pro fret job would likely nullify any issues and let me go lower on the relief.