Flatiron OM as mandocello?

[Michael Eck]

Hi All,

I have an 80s Flatiron 3K Octave Mandolin, with 23 3/8 scale. Can I safely string this as a mandocello? Has anyone tried this with good results? If so, thoughts on best gauges?

Thank you!

[blaise.douros]

Hi All,

I have an 80s Flatiron 3K Octave Mandolin, with 23 3/8 scale. Can I safely string this as a mandocello? Has anyone tried this with good results? If so, thoughts on best gauges?

Thank you!

If you know the current string gauges, you can calculate an equivalent set for mandocello tuning using http://stringtensionpro.com/

Plug in all the specs for your current string set and OM, and it will give you a rough idea of how much tension is on each string. Then you go back to the earlier step of setting the tuning, change it to CGDA, go back to the tension results, and play with it until you get equivalent values. You'll probably end up with some seriously big gauges on the low end, but I bet it's not impossible.

[Dacraw54]

Even moderate to light gauges on the C (.065") and G strings will have high tension at pitch - standard .075" C strings are probably out of the question. The Flatiron OM is a flat-top and may not take the increased pressure. I would email Bruce Webber and ask his opinion.

[allenhopkins]

I also own a 3K OM and would be tres cautious about heavier strings. After all, for all its many virtues (I've played mine since around 1985) it's a "pancake" design without any top arch. I'd speculate that a "C" string light enough to protect the instrument's integrity, would be pretty "floppy" in that tuning, and not give you the bass you'd want.

[blaise.douros]

One solution might be to run single C and G strings in a heavier gauge, so as to maintain adequate tension. But I would still try the string calculator first.

[trevor]

I agree with Allen, they are lightly built instruments not made for higher string tension.

[blaise.douros]

I agree with Allen, they are lightly built instruments not made for higher string tension.

With the proper gauges, the string tension would be the same--hence my suggestion to run the numbers on the string tension calculator. Whether or not the gauges are realistic are another matter, but it IS theoretically possible to put the correct gauge strings on and have no change in the tension.

[allenhopkins]

With the proper gauges, the string tension would be the same--hence my suggestion to run the numbers on the string tension calculator. Whether or not the gauges are realistic are another matter, but it IS theoretically possible to put the correct gauge strings on and have no change in the tension.

I agree totally -- it's possible to assemble a set of CGDA strings in gauges that will keep the same tension level.

The question is, what would that string set-up sound like? Would the C string have to be so light that it would not give a real mandocello sound?

It would make sense to investigate what gauges of strings would keep the overall tension load on the top around the same level as the octave mandolin set. And that might be worth a tryout. But my overall recommendation would be to use an instrument designed to be played in the mandocello range.

If you do go ahead and restring the Flatiron, let us know how it comes out. But be careful not to overload the top and its bracing.

[colorado_al]

I'd use the same strings that you use now for the G D & A courses, but only use a single on the G and try a .070 single for the C. You might even be able to do a .075. you likely will have to ream out the hole in the tuning post for a C of that size

[colorado_al]

Looking at the string tension calculator, you might get away with it.
If you're using EJ80 octave mandolin strings on that instrument, your total tension as an OM is 189#.
The E strings are 19.63# each.
If you keep the same G, D & A strings and add 2 .070 PB strings for the C, the C strings would be 22.35# each. So you'd add 2.72# per string swap, a total gain of 5.44# by removing the E strings and adding C strings. If you're nervous about adding tension, a single C string would actually lower the total by 17#.
Or you could slightly size down the A or D course (or both) by one gauge.

Here's the calculations with EJ80 at 23.375 inches


And here's the calculations removing the Es and adding .070 Cs


If you size down the A and D courses one size, you could actually go to a .074 C course and still have lower tension than the EJ80 OM strings at 188#


The question that I'm interested in is what is the nut width of your OM? You might not have the width to size up to 2 C strings anyhow. If it is less than 1.5 inches, you'll likely need to do a single C string. If I remember correctly, the Flatiron OM was about 37mm which is just a hair under 1.5" and would probably work. What does yours measure?

[Michael Eck]

That's the width on mine.

I want to thank all, as always, for the knowledge. I think I'm going to leave this fine instrument as is!