Octave mandoline string spacing

[Rob Grant]

Anybody have any references on octave mandolin saddle and nut string spacing. I'm working on an instrument with a 585mm (~23 inch) string length. Mandola stats should put me in the right ball park, but I thought it might help to dredge up a few personal experiences from other builders. Any feedback appreciated.

The lanky "Beast" under construction. 100% Oz timbers including the Athrotaxis selaginoides top..

[Rob Grant]

Sorry for the spelling error on the subject line. No, I'm not referring to the kitchen utensil.<G>

[Michael Lewis]

Rob, do you need actual measurements or just some guidelines? There are several old posts here on the 'cafe addressing this.

I start with the two outside strings, set them in from the edge about 2mm or so depending on the ends of the frets. Once they are established you can set the next two strings of the outside pairs, and once they are set you just have to divide the remaining space for the other two courses.

[Rob Grant]

Michael,

Many thanks for responding. The basic guidlines are helpful. What I'm a bit concerned about is those big floppy G strings with a 585mm SL. Do you reckon 2mm spacing between the individual Gs is sufficient? Any wider and they will be difficult to fret as a pair. Any closer and I think they may "rattle" against each other. I'm using a bit of a rare and beautiful material for the nut and saddle, so I'd like to hit the spacing right on the first go.

[Graham McDonald]

Someone else asked almost the same question a couple of weeks ago. Here are my diagrams for OM/bouzouki nut and strings spacing. The distance between the courses can be altered proportionally to suit your overall nut and saddle width, but the intra-course spacing will usually work.

cheers

graham

[Rob Grant]

Graham,

Thanks for that very helpful diagram. I seem to have missed it the last time around and I couldn't locate it with my usual lame choice of search engine wording. You've got my vote for "National Treasure" if our Julia decides to institute a new program.<G>

Thanks again,

Rob

[amowry]

I've used Grahams's spacing for about a dozen octaves with no complaints yet.

[Rob Grant]

I just grabbed my copy of Graham's "The Bouzouki Book" down from the book shelf. I've had this valuable reference since it came out around 2004. Situated clearly on page 108 is exactly what I wanted (the same diagram!). Seems there's a whole lot of other interesting bits that I have forgotten or missed since the last time I had this down... time for another read!<g>

Thanks again.

[Michael Lewis]

Hey Rob, make a sacraficial nut and saddle to get your spacing and once you have everything working well THEN make the permanent ones of your rare material.

[Rob Grant]

That is a good idea Michael and I do appreciate the advice, but time and somewhat limited enthusiasm (attention span??<g>) pushes me to get the bloody thing right the first time around.<G>

[colorado_al]

Thanks for the diagram! Exactly what I needed for the nut on my Blueridge B40TCE tenor guitar, in order to turn it into an 8 string octave mandolin. The nut is 32mm, so I reduced the space between courses, and the bass side edge, by 0.5mm.

[MISTAHCOUGHDROP]

Hello all, I'm a bit late to this thread, but just acquired a Fletcher Brock Octave. I had someone recut the nut and saddle for unison strings but find the fretting of the strings to be a bit strange – the double strings "split" somewhat under the pressure of my fingers. I've watched S. Jarosz and S. Hull playing octaves and noted that they do not seem to have that issue. I've written Fletcher and he said that 1/8th of an inch is what he designed it to be but I'm feeling the strings to be a bit loose and moving apart. He said I would figure out a way to fret the strings w/out the issue. But I'm a bit frustrated – it feels strange. I could possibly have a new nut and saddle cut here in Paris. Thanks for any help. Best, M.

[peter.coombe]

What an incredible coincidence. I have just strung up my first octave mandolin (about an hour ago), but worked out the spacing myself. It came out very close to Grahams's, but I used a Brekke bridge with different compensation because all the strings are wound and is 21inch scale length. It uses a technique I have adapted from the guitar research in the design and is astonishing good sounding, especially considering it is a flat top and my first octave. I will talk later about what I think I have discovered, it is ground breaking stuff, and this is not the first time I have used the technique and got amazing results. Graham McDonald has called it the holy grail of Lutherie, but since it might just be the holy grail of Lutherie I need more data, i.e. more points on the line and a proper statistical analysis to prove it. That takes time, more measurements, and more mandolins. If it goes well (so far so good) all will be revealed in due course in the GAL.

[colorado_al]

I've since modified the string spacing on my Blueridge to 3mm between the G course and 2.5mm between the D course, exactly for this reason.
I would have the nut remade to bring those courses closer together. However as they get closer, you run the risk of the strings interfering with each other.

[MISTAHCOUGHDROP]

Thanks Colorado Al, but you would also modify the bridge as well as the nut spacing? I've watched videos of Jarosz and Hull playing octaves and do not see the strings separate at all. What would you recommend? A new nut and a new bridge? with spacing at the bridge at 3 mm and 2.5 mm respectively between the G and D strings? Thanks! M.

[colorado_al]

I personally would also modify the bridge saddle slots.
If you have an adjustable bridge, you can file the top of the saddle down to remove the old slots and cut in new slots and then bring the action back up with the adjustment screws.
Or you can go with a new saddle that fits on your bridge, or a new bridge entirely, if you like.
My preference would to be to get a new nut and saddle made with the new spacing. Then you can switch back to the old ones if you end up not liking it. Or swap back and forth to test.

[WoodyCTA102]

Great information.

Just a couple of weeks ago made an ebony bridge saddle for my Apollonio bouzouki. Ended up guessing at the string spacing, came out pretty close. Next time, I'll have this info to make it perfect. Thanks.