G strings separate under finger

[Ron McMillan]

I have a new mandolin that arrived from the other side of the world with several things wrong with it, but for a variety of reasons we won't go into here, I am unable to return it - and have to get it sorted myself.

One of the problems I have when playing it is that the G strings sometimes 'separate' when I finger them. i.e. on fingering, the string space opens up and my finger is having trouble holding them both down cleanly because the strings are splitting up and part of my little finger is going through the gap to the fingerboard. I am fairly certain that this is not a problem with my playing technique, as it has never happened with any other mandolin I have played, including the other two I own now.

At first I thought there was a string tension problem, but now I am thinking it might be due to the nut slots for the G string being too far apart.

Might I be on the right track? If so, a new nut might solve a problem that is making my expensive new mandolin not much fun to play.

I could get a guitar luthier here in Thailand to make me a new nut, but I'd rather not hand the instrument over to someone with no experience of mandolins. In the past I have used a Graphtech Tusq nut as a replacement on another instrument. At least with the Graphtech I can order it pre-slotted from the USA knowing the precise dimensions of what I am buying, and be fairly sure that I am getting something I can adapt to my needs. Any thoughts on that?

Another issue that may be related to the above problem: the tailpiece is installed not exactly parallel to the mandolin top. It slants slightly, with the bass side of the tailpiece perceptibly higher off the top than the treble side. Is this an error by the maker, or is it normal to elevate the bass side of the tailpiece a little? If it is a flaw in the manufacture, can this be affecting tension in the G strings, adding to the fingering problem mentioned above?

Thanks in advance,

ron

[sunburst]

You're probably right about the G-string pair being spaced too wide for your fingers. A new nut would need to be fitted to the particular mandolin by someone who knows how, but that should solve the problem. The bridge spacing could be contributing to the problem too, but it's probably mostly (if not completely) the nut.
The tailpiece issue is of no particular importance and has nothing to do with the string separating problem.

[Ivan Kelsall]

One other thing that could be a cause of the strings opening up,is the nut slot depth. If the slots are too shallow,then the larger diameter G strings could be squeezed out of the slots by finger pressure.It could be that the total depth of the nut is incorrect & the G string slots couldn't be cut any deeper without causing some string buzz.
Just refer to your other mandolin Ron, & do a bit of comparing slot / nut height & slot depth / spacing. Re.the tailpiece - boththe treble & bass sides should be at the same height above the body of the mandolin. Having seen the pic.that you sent me,it's a fitting error which shouldn't have happened. But as John says,that shouldn't affect the strings,as there's still the back pressure from the tailpiece pulling the strings down into the bridge slots,
Ivan

[whistler]

It sounds most likely to be a string spacing issue. Ditto Ivan: compare it with your other mandolin - the difference may well be clearly visible. Nevertheless, take measurements as precisely as you can (with a 0.5mm-graduated rule - or a vernier caliper, if you have one); measure the slot spacings centreline-to-centreline. In addition to the spacing between the G strings, pay attention to the spacing between the G and D strings and the total string pitch (G to E), since one or other of these will be affected by any change to the G string spacing.

If your local guitar luthier is a good guitar luthier, they should be able to fit you a new nut. But you first need to ascertain exactly what it is that needs changing - and what needs to stay the same - and convey that clearly to the luthier.

[bart mcneil]

These are not significant problems, but obviously your mandolin needs to be properly set up. Mail order mandos from discount sellers almost never are, and most of them need the kind of adjustment you are concerned about. There are sites and threads on setting up your own mando if you are interested in doing it yourself or understanding what is checked and adjusted by a professional to make things right. Frets,com is an excellent source of informattion on setting up a stringed instrument.

And while you are at it, the tailpiece can be removed the screw holes filled and the tailpiece re-positioned. the old filled screw holes won't show as they will be under the tailpiece metal.

[High Lonesome Valley]

Find a good guitar luthier, give him the specs. Mail order setup could be a disaster. Here's a gauging guide.

http://www.mandolinluthier.com/nut_fitting.htm

[bart mcneil]

I mis-stated the address for fret.com. It is frets.com not frets,com.

[Ron McMillan]

A follow-up question that I know is striking for the ignorance it illustrates on my part. It just occurred to me that the mandolin in question has a radiused fretboard. Pre-slotted TUSQ nuts appear not to be radiused. Apart from getting a blank nut and having a radiused one custom-made based on the existing one (but with spacing on the G strings corrected), what other options might I have?

Are there other makers of quality pre-slotted, radiused mandolin nuts out there?

Or is it practical to 'add a radius' to an unradiused nut by adjusting the depths of the nut slots? If this is the most stupid idea you ever heard, don't be shy to tell me. :)


ron

[Ivan Kelsall]

If you can get a blank Tusq nut of sufficient depth,simply sand the top to a radius to suit the fingerboard & / or existing nut after removal,& then cut the slots. Regarding the spacing of the strings for a new nut,again, i'd use your other mandolin as a guide. If the spacing of the D,A & E strings is ok,just concentrate on getting the G string spacing & slot depth correct. You could very well add slots which sit along a radius in a 'flat topped' nut,but it might look a bit odd. I've made dozens of banjo nuts in the past ,all 'flat' of course,my only run in with something that shoud have been radiused,was the CA bridge i fitted to my first Lebeda mandolin.I simply took the saddle off & sanded it to the same radius as the old saddle,slotted it & re-fitted it. It worked perfectly. There's no reason to think that doing the same to a new nut wouldn't work just as well,
Ivan;)

[Bill Snyder]

Your idea of radiusing a preslotted TUSQ nut and deepening the slots as needed should work if the slots are in the correct position and it is tall enough.

[EdHanrahan]

Or is it practical to 'add a radius' to an unradiused nut by adjusting the depths of the nut slots? If this is the most stupid idea ...

Not at all stupid! It's pretty much mandatory if the slots are cut correctly. What I would do is get your slots correct in relation to the frets, and worry about radiusing the top of the nut only as an afterthought.

(As others have said previously, it's unlikely that any new nut is going to fit your instrument exactly. Far safer to assume that every nut will need fitting to your specific requirements... even your current one).

Remember that the strings, theoretically, should sit only half-way down into the slots. If your current (and non-radiused) bottoms of the G-string slots are higher (from where they need to be) by half the width of the G-strings themselves (that would be about .020", assuming the the Gs are a typical .040" or so), then I'd just cut new slots, or adjust the current ones, in whatever location & depth they need to be.

(Yeouch! That sentence is a mouthful... sorry!)

By referencing the slots' bottoms to the frets, they should automatically come out as radiused. Later on, you can simply file the top of the nut down to half the depths of the slots and, again, it will be radiused. Plus, the bottoms of any prior & too-high slots should end up being filed away. At the very worst, the remnants of now-unused slots may be apparent, but you will have gotten lots of experience to apply to a replacement nut!

[Ron McMillan]

Thanks, Ed. I'll have to think about this one.... :)