Has anyone looked into modding the neck to make a mandolin?

[Rob Welch]

I'll introduce myself.  I'm 'welchomatic' on thingiverse if anyone wants to see my designs.  With the exception of a photogrammetry project, my designs consist mostly of right angles and circles.  I can do more as far as part design, but only through sheer force of will.  In other words, I'm solidly in the Hobbyist circle with regard to Solid Object Modelling.

I saw the Modular Fiddle in Make Magazine and initially did nothing more than note that it looked like an interesting project.  I play Bluegrass music on all instruments known for that genre except the fiddle.  My adult daughter took up the fiddle.  My brother gave her his old elementary school violin that he hadn't thought of in 30 years.  But when I put $300 into it to make it playable, and my daughter got a few songs under her belt, my brother asked for it back.  Now the Make article was very important to me!  My kid is a Forester, so I made her a brown and emerald green violin for her Christmas gift.  And I made myself a brown and black one.  And bought the plans for the 5 string version, which I am making for my daughter, as she wants to be able to switch between violin songs and viola/cello songs.

What I'm wondering is if anyone has looked into the amount of stress the bout would take if I were to convert the neck, tuning board, bridge and tailpiece to a Mandolin.  I think I can modify the existing parts to do this, making both a 'insert your own metal frets' version, and a 'printed ridges as a fret' version.  But if this has already been looked into and dismissed, I wouldn't want to waste the effort on a certain failure.

[Robert Peng]

I think the main thing to pops into mind here for me is that ridge between the fiddle end piece has a tendency to crack as time passes, may need to create something to disperse the tension from the 4 additional springs

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[David Perry]

Hey Rob (Welchomatic),

Thingiverse says your in Atlanta -- that's where I grew up! Somewhere between Virginia Highlands and the strip club with the neon helicopter. Good times. My mom is still in the area and plays bass -- makes it out to a lot of bluegrass jams. 

Hey, one can do a lot with right angles and circles! 

Thank you for purchasing the 5-string plans. Let me know if you have trouble with anything, but if you already built a 4-string it should be pretty straight-forward. Another thing you might consider is making another 4-string but putting octave violin strings on it. I have one and I LOVE it. That would give you a true cello range, and a badass low fiddle.

I want to say that mando strings would be too much tension. You might need to beef up the joints between pegbox/neck and neck/body. I think that's what Robert is getting at, above. Let's assume you can get the joints strong enough...then you need to make sure your tailpiece can take it, and that is no small matter. The tailpiece for the hardanger fiddle has proven tricky.  If you use a standard nylon gut -- the threaded metal stops on the nylon cord will probably rip off from the total force of the 9 strings. OK, so then you wire it to the body, that works, but it puts the tailpiece in a worse loading condition (bending). So you'll need a strong tailpiece one way or the other.

Let's assume the tailpiece is good -- now we're just talking force down on the top plate of the body. For a typical mando, the total downward force at the bridge is about 40 pounds. For a fiddle, typical is about 20 pounds. This would not work. The top plate may not fail immediately, but it will deform fairly quickly over time (creep). You can just thicken the plates, though, and that may do the trick. 

All in all, I don't think it's impossible, but you'll have to change all the parts. 

I've been wanting to build a ukelele neck/pegbox/tailpiece for the body. Maybe you could use uke strings to make a mando with less string tension? Lots of possibilities out there...

-David

[David Perry]

Or maybe you could do this...

From this page.

[Rob Welch]

Wow!  I can't even begin to imagine the stress the body must be under with all those strings.  That is an interesting solution to a problem I would never have guessed existed.  Although I do know in smaller jams I have had instrument stands around my chair and between lead breaks have been known to put one instrument down and pick another one up.  Flipping it over instead is an interesting solution.

Before I take on a mandolin neck, I'm going to use my expertise in right angles and circles to make a 5 string mute to be printed with TPE.  My wife just can't handle me learning how to play a violin at full volume and my 4 string mute won't fit.  Stay tuned!

Regarding my 'let the idea simmer a while' for the Mandolin, I think I'll use a stamped tailpiece from StewMac or Elderly, or might even fold and drill my own out of metal.  Then the problem becomes more about not cutting the plastic than not deforming it.  And as far as Robert's concern about cracking at the End Piece, Hey, I've got a printer and a file!  I can just make a new one when that happens!

One question - I can't see a difference between the two bout files you share - 4mm and 62mm.  Could you provide insight?

Also, I would bet that I don't know your mom, but am highly likely to recognize her if a picture was made available.  See if she is a regular at Everett's Music Barn in Suwannee GA on Saturday nights.  If so, then I have most definitely listened to her play, and there's a good chance I've played alongside her.

[David Perry]

I know isn't that mando/violin thing crazy? What a great bar trick though...oh let me get my mando...flip! 

Ah, nice, a mute! There's an Oregon company that makes 3D printed mutes that are pretty cool...shoot their name escapes me at the moment.

Oh yeah -- those were made by another maker here -- they modeled supports for the body so that you can print without support and don't have to add support in your slicer manually. The 4mm is for .35mm nozzles and the 62mm is for larger 0.5mm nozzles. 

-David