A question regarding floating bridges

[simplygoodmusic]

I have just started to plan my guitar to mandocello, and I am gonna use an old yamaha all laminate guitar I have.

I have planned most of it, but I dont know what to do with the bridge. I have been told a floating bridge simply won't work on flat topped, x braced instruments. Is this true? Why?

[PT66]

It is possible to use a floating bridge with a flat top and x bracing. But it looks pretty ugly when you remove a pin bridge and there will be holes in the top where the pins where. I would plug the holes in the bridge and redrill for eight pins.

[PT66]

Check out this. http://www.frets.com/FRETSPa....rt.html (http://www.frets.com/FRETSPages/Luthier/Technique/Guitar/Structural/8StConvert/8stconvert.html)

[simplygoodmusic]

Thanks dave.

I am not too worried about the looks. I do know I can go with the other bridge , i.e the normal guitar one, I just thought it would sound more mandocelloish with a floating one. Though I am told it "isn't made for it" and the guitar would be "over-braced", whatever that may mean.

I might go half half...keep the bridge, but install a tail piece, so its not really floating, but still more mandocelloish.

[PT66]

It is possible to lighten the bracing through the sound hole. I believe there are picture of this technique in Erving Sloane's book on Guitar Repair. Donald Dech at C.F. Martin showed me how many years ago.

[simplygoodmusic]

Erm... I am a little scared, as apparantly the 10 string ( I should have mentioned its actually a cittern/mandocello) is high enough as it is... and with weak braces I am afraid it might not hold up.

Am I wrong?

[PT66]

This is staring to feel like a conversation between the two of us. I think the only way you are going to know how it sounds is go for it. I wouldn't worry about it not taking the tension. Do you think you can fit 10 tuners on the head? What do you plan to use for a tailpiece? I would base your string gauges on guitar string of similar pitch.

[markishandsome]

I don' t think there is one standardized "madocelloish" sound that you need to shoot for here. It won't sound like an old Gibson archtop 'cello no matter what you do. I would take the path of least resistance and do whatever is the easiest posible conversion you think you can do involving the least amount of modification. I just think you'll be disapoiunted if you spend 6 months reworking the thing and making it look pretty and it still sounds just like the same old plywood yamaha (which it will).

[simplygoodmusic]

I am well aware that it won't sound like a mandocello - I am doing this as a fun project to learn, and hopefully have something to learn on. And the yamaha sounds pretty good. I am NOT expecting a perfect mandocello sound. But if I can work things to make it better, I want to - thats the idea of the project.

I've calculated tensions, and I think I'll get it to about 200lbf...which is not small but the neck should take it.

For the tailpiece I am planning to use a Allen TR-10..the only 10 string I can find. And you are right, I guess I better just go for it. I'm going with floating, I just gotta figure out how to solve the break angle issues...but thats been done before, and with a little bit of imagination it'll be possible:D

[markishandsome]

I never said it would sound bad or that it wouldn't sound like a mandocello. I said that there isn't really such a thing as one definitive "mandocello sound". They're relatively rare instruments that come in a relatively great variety of styles. I'd even venture to guess that the majority of what we might call mandocelli built over the years have been flat-tops made for Irish styles, many with a floating bridge like you plan to use. Lots of old parlor guitars have the same configuration. They sound different from pinned-bridge guitars, but they still sound like guitars. What style of music do you intend to play on this instrument, and what style of mandocello do you think typifies THE "mandocello sound"?

You could use a trapeze tailpiece modified to take 10 strings, or a 12-string tailpiece and only use 10. To really increase the break angle at the bridge (maybe not a good idea with that much tension anyway?) you'd need to reset the neck at a greater angle. If it were me, I'd just string it up as is and see how I liked the sound with the small break angle. If it were a real dog I might consider further surgery.

[Michael Lewis]

Why not take the easier route and get a 12 string and leave off one course?

Have you laid out the string spacing at the nut? Do you have enough room for your 5 courses? You could plug and redrill the headstock for a set of mandolin machines plus a couple banjo planet pegs, or rework the whole headstock adding some length, veneers, and a huge thick back strap. That would get the neck working if it is wide enough for your strings, now about the bridge. Replace the bridge and bridge plate with suitable items for 10 strings, then you might need to add a JLD Bridge Doctor to keep the top flat. You really want to do this?

You could take the easier route and get a 12 string . . . . . . . . . . http://www.mandolincafe.net/iB_html/non-cgi/emoticons/coffee.gif

[man dough nollij]

I have an ignorant noob question about this... Will the fret spacing on a guitar neck (for instance) always be the same for that scale length, no matter what gauge and tension of strings is put on? It just seems weird that a guitar would automatically become a cello with just thicker strings added. Following that reasoning, if you tuned a mandola to GDAE, it would be a 17"-ish scale mandolin in every way, right? It seems like it would be really hard to calculate what gauge strings to use-- you could snap the neck off if you guessed wrong.

[Bill Snyder]

Fret spacing for any given scale is not dependent on string gauge. The frets go in the same place on a 24.75 inch scale no matter whether it is tuned like a guitar or a mando family instrument.
As far as tuning a 17" scale instrument to the pitches of a mandolin it will not work. I am just darn near certain that you will never get the E string tuned up to pitch before it breaks.

[markishandsome]

A friend of mine once broke his mother's old classical guitar in half putting steel strings on it. There are various string gauge calculators available online to help with this sort of thing. You usually want to have in the neighborhood of 20 lbs tension in each string (to much more and the string snaps, to much less and it's too floppy) and if you know the scale length you can just plug a few different gauges in until it works out. You'll find that for a given pitch and scale, only a few different gauges will work. Then if becomes a personal choice whether you like light medium or heavy.

[simplygoodmusic]

I never said it would sound bad or that it wouldn't sound like a mandocello. I said that there isn't really such a thing as one definitive "mandocello sound". They're relatively rare instruments that come in a relatively great variety of styles. I'd even venture to guess that the majority of what we might call mandocelli built over the years have been flat-tops made for Irish styles, many with a floating bridge like you plan to use. Lots of old parlor guitars have the same configuration. They sound different from pinned-bridge guitars, but they still sound like guitars. What style of music do you intend to play on this instrument, and what style of mandocello do you think typifies THE "mandocello sound"?

You could use a trapeze tailpiece modified to take 10 strings, or a 12-string tailpiece and only use 10. To really increase the break angle at the bridge (maybe not a good idea with that much tension anyway?) you'd need to reset the neck at a greater angle. If it were me, I'd just string it up as is and see how I liked the sound with the small break angle. If it were a real dog I might consider further surgery.
Fair enough. I don't have any preference really... when I think mandocello I think of a sound I am obviously NOT going to get, and thats the Mike Marshall sound, but in all honesty, I am just having fun creating something new here.

[simplygoodmusic]

Why not take the easier route and get a 12 string and leave off one course?

Have you laid out the string spacing at the nut? Do you have enough room for your 5 courses? You could plug and redrill the headstock for a set of mandolin machines plus a couple banjo planet pegs, or rework the whole headstock adding some length, veneers, and a huge thick back strap. That would get the neck working if it is wide enough for your strings, now about the bridge. Replace the bridge and bridge plate with suitable items for 10 strings, then you might need to add a JLD Bridge Doctor to keep the top flat. You really want to do this?

You could take the easier route and get a 12 string . . . . . . . . . . http://www.mandolincafe.net/iB_html/non-cgi/emoticons/coffee.gif
I've checked the spacing, and I've got enough space for the 5 (1 3/4 spacing). I was originally planning on having the headstock all banjo tuners... too crazy? It should fit on the headstock if I fill in the holes and redrill.

As for the 12 idea...not that I am not listening to you here. I admire your work, and I know you know what you are talking about. But the whole point of this is to use my yamaha, and I don't mind the extra work it is creating - this is fun for me!

I am using a string tension calculator and I really can't get it much less then 200lbf. I'll check online, and if the recommended tension is anything less than 180 (which I am told is standard for laminates?), I'll go with 4 courses.

[Martin Jonas]

As it happens, there is a page at frets.com about adding a tailpiece to a guitar with pin bridge, too, but I wouldn't say it has Frank's seal of approval...

Link (http://www.frets.com/FRETSPages/History/UsedToBe/usedtobe1.html)

http://www.frets.com/FRETSPages/History/UsedToBe/UsedToBeViews/tpstrap.jpg

Martin

[8ch(pl)]

You may be applying pressure in a direction not originally intended. The pin bridge on a guitar is designed to have upward,forward tension and the top is braced with this in mind. A tailpiece and floating bridge apply downward pressure.

[markishandsome]

There's only one way to find out if the Yamaha will handle the string load in this configuration: try it and see! If it doesn't work out it will just give you an excuse to try again. http://www.mandolincafe.net/iB_html/non-cgi/emoticons/smile.gif

[PT66]

"I am using a string tension calculator and I really can't get it much less then 200lbf. I'll check online, and if the recommended tension is anything less than 180 (which I am told is standard for laminates?), I'll go with 4 courses."
The 180 is for a pin bridge pulling up on the top. With a tailpiece you don't have that. I feel that you get can put a lot more pull on a tailpiece.