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Jan 20, 2020 - 6:54:39 AM
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47 posts since 11/14/2018

I am building a banjo out of aerospace grade materials (mostly discards being repurposed) for the fun of it. I'm not sure if it will sound good but I don't really care - the journey is the destination; I like to make stuff. If it happens to sound OK I will take it backpacking (backpacking banjo) - my weight goal is around 1.5 pounds or less. I would like it to be water resistant and light so that is why I'm looking at a carbon fiber neck. It might have an epoxy impregnated wooden fret board, I'm still thinking about that.... The pot end is aluminum with a kevlar hoop. Another design goal was to make it rugged because it will get abused out on the trail. Amplification of sound isn't that important because its for entertaining only me and maybe one or two other people. A panjo was my original inspiration.

Its going to be headless and I'm working on the tuner now. The tuner is a compact arrangement of levers that will be mounted on the pot end. This gets the center of gravity down on the pot end and saves some weight also.

Anyhow, if anyone has some experience with making a carbon fiber neck I'd appreciate any ideas or tips you might have. I can either make a balsa plug and cover it with carbon fiber layers or make a female mold (way more work) and mold it. It may require a reinforcing rod of carbon fiber also. I haven't though through that yet.

I work with composites in my job so I basically know how to do this but lessons learned from someone who has done it are invalueable.

Jan 20, 2020 - 7:14:36 AM

2058 posts since 12/31/2005

Why a separate fretboard? That is just something that might try to expand and contract independently, leading to separation. Graphite necks incorporate fretboard. I am fascinated by this project. There is actually a place in the market for impervious instruments. Cost would be the biggest challenge. But I realize you are doing this for your own enjoyment. Plz post pics along the way.

Jan 20, 2020 - 8:18:59 AM

39 posts since 3/13/2014

Doesn't Gold Tone offer a carbon fiber neck?

Jan 20, 2020 - 9:01:48 AM

Banjo40

USA

632 posts since 9/6/2004

Jan 20, 2020 - 9:06:14 AM

1827 posts since 2/28/2003

I've never made a full-on carbon fiber neck, but I have made a few ultra lightweight headless necks with CF reinforcement instead of a truss rod. That will save you quite a bit of weight, and with a light weight wood you can get the neck below 1.5 lbs easily. The lightest neck I've made was about 1.1 lbs. I've found curly maple is the lightest, strongest wood I've tried and will save you a few ounces over hard maple or walnut. Mahogany might be lighter but I've never tried it. 

I get carbon fiber strips from Dragonplate, sized .125 x .375 in, and epoxy 2 of them side by side into the truss rod slot. That's plenty strong for steel banjo strings but of course you won't be able to adjust the relief. If you start with a dead-straight neck the string tension should take care of that.

With the CF neck and using a bamboo body reinforcement "dowel stick" instead of the standard extruded aluminum bar, I've made a few of my Tranjo Express travel banjos that weighed in at around 2.25 lbs overall. Tranjo Express III

Sam Farris

Edited by - sdfarris on 01/20/2020 09:08:58

Jan 20, 2020 - 9:50:21 AM

47 posts since 11/14/2018

quote:
Originally posted by Brian Murphy

Why a separate fretboard? That is just something that might try to expand and contract independently, leading to separation. Graphite necks incorporate fretboard. I am fascinated by this project. There is actually a place in the market for impervious instruments. Cost would be the biggest challenge. But I realize you are doing this for your own enjoyment. Plz post pics along the way.


Thanks.  So far I've spent about $10 on it and I have the pot and most of what I need for it done.  Often you can buy expired composite prepreg or off cuts  on ebay cheap.  You don't need top quality composites for a banjo.  Aircraft quality is needed for airplanes butnot necessarily for DIY projects that don't leave the ground.  I've been working on this along with a bunch of other projects for over a year.  It may not be done for a while!  

The incorporated fretboard might work for me but I like the look of the low tech wood against modern materials.

Jan 20, 2020 - 9:52:44 AM

47 posts since 11/14/2018

quote:
Originally posted by Banjo40

goldtonemusicgroup.com/goldtone/parts/gn2f


Thanks but a headless stringed instrument doesn't have the tuners at the end of the neck.  That won't work for me without modifying it and if I have to get dirty working with composites I'd rather just start from scratch.

Jan 20, 2020 - 9:54:27 AM

6737 posts since 8/28/2013
Online Now

I'd like to see what you come up with for your tuners. I've sometimes wondered why banjos and other string instruments are tuned from the peghead, which can throw the instrument out of balance.

Jan 20, 2020 - 9:59:24 AM

47 posts since 11/14/2018

quote:
Originally posted by sdfarris

I've never made a full-on carbon fiber neck, but I have made a few ultra lightweight headless necks with CF reinforcement instead of a truss rod. That will save you quite a bit of weight, and with a light weight wood you can get the neck below 1.5 lbs easily. The lightest neck I've made was about 1.1 lbs. I've found curly maple is the lightest, strongest wood I've tried and will save you a few ounces over hard maple or walnut. Mahogany might be lighter but I've never tried it. 

I get carbon fiber strips from Dragonplate, sized .125 x .375 in, and epoxy 2 of them side by side into the truss rod slot. That's plenty strong for steel banjo strings but of course you won't be able to adjust the relief. If you start with a dead-straight neck the string tension should take care of that.

With the CF neck and using a bamboo body reinforcement "dowel stick" instead of the standard extruded aluminum bar, I've made a few of my Tranjo Express travel banjos that weighed in at around 2.25 lbs overall. Tranjo Express III

Sam Farris


Thanks, that's a nice banjo you make.  I'm shooting for 1.5 lbs or less total.  Its easily done, I believe, if using high strength ultralight materials.  That said, I'm doing this for fun and haven't made an engineering project out of it.  I've been chosing light materials when I have to make a decision.  Hopefully, I'll make my weight goal.  But, I don't want to make a spreadsheet and design this in my head because it will take the fun out of just doing it as I go.

Jan 20, 2020 - 10:10:51 AM

47 posts since 11/14/2018

quote:
Originally posted by G Edward Porgie

I'd like to see what you come up with for your tuners. I've sometimes wondered why banjos and other string instruments are tuned from the peghead, which can throw the instrument out of balance.


google Tuning-Tailstop-3a and you'll find a pdf of what I'm using.  I've modified that design to just have 5 tuners instead of 6.  The person who did that did a beautiful job of providing drawings and all the details.  I haven't decided whether I'll use the ultra fine tuners and bushings or go out on my own and use 8-32 stainless fasteners for the tuning screws.  Its a 35 cents each versus about $8 to $15  each (depending on the options) comparison.  The ultra fines would be nice because they are 100 threads per inch, but they are spendy and violate my idea of using free, nearly free or cheap materials.  A panjo is supposed to be "found stuff.  My 5th string will be full length will a "railroad spike" at the right spot on the fret board.

Edited by - 98v70dad on 01/20/2020 10:12:36

Jan 20, 2020 - 10:14:31 AM

47 posts since 11/14/2018

quote:
Originally posted by 98v70dad
quote:
Originally posted by Brian Murphy

Why a separate fretboard? That is just something that might try to expand and contract independently, leading to separation. Graphite necks incorporate fretboard. I am fascinated by this project. There is actually a place in the market for impervious instruments. Cost would be the biggest challenge. But I realize you are doing this for your own enjoyment. Plz post pics along the way.


Thanks.  So far I've spent about $10 on it and I have the pot and most of what I need for it.  Often you can buy expired composite prepreg or off cuts  on ebay cheap.  You don't need top quality composites for a banjo.  Aircraft quality is needed for airplanes but not necessarily for DIY projects that don't leave the ground.  I've been working on this along with a bunch of other projects for over a year.  It may not be done for a while!  

The incorporated fretboard might work for me but I like the look of the low tech wood against modern materials.


Jan 20, 2020 - 12:04:34 PM
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Banjo40

USA

632 posts since 9/6/2004

Here is a video of Gordon Acri’s headless banjo. I saw it years ago at the IBMA World of Bluegrass, but I don’t remember the details about his tuners.
youtu.be/0PT6VfyCitQ

Jan 20, 2020 - 1:00:37 PM

47 posts since 11/14/2018

quote:
Originally posted by 98v70dad
quote:
Originally posted by Brian Murphy

Why a separate fretboard? That is just something that might try to expand and contract independently, leading to separation. Graphite necks incorporate fretboard. I am fascinated by this project. There is actually a place in the market for impervious instruments. Cost would be the biggest challenge. But I realize you are doing this for your own enjoyment. Plz post pics along the way.


Thanks.  So far I've spent about $10 on it and I have the pot and most of what I need to complete it.  Often you can buy expired composite prepreg (preimpregnated with resin) or off cuts  on ebay cheap.  You don't need top quality composites for a banjo.  Aircraft quality is needed for airplanes but not necessarily for DIY projects that don't leave the ground.  I've been working on this along with a bunch of other projects for over a year.  It may not be done for a while!  

The incorporated fretboard might work for me but I like the look of the low tech wood against modern materials.


Jan 20, 2020 - 7:43:28 PM

1981 posts since 2/7/2008

quote:
Originally posted by sdfarris

I've never made a full-on carbon fiber neck, but I have made a few ultra lightweight headless necks with CF reinforcement instead of a truss rod. 


I’d be very interested to learn more about this for a project I’m planning.

How did you do the tuners for your headless neck?

Jan 21, 2020 - 8:56:17 AM

1827 posts since 2/28/2003

quote:
Originally posted by Quickstep192
quote:
Originally posted by sdfarris

I've never made a full-on carbon fiber neck, but I have made a few ultra lightweight headless necks with CF reinforcement instead of a truss rod. 


I’d be very interested to learn more about this for a project I’m planning.

For my Tranjo travel banjos, I use Steinberger gearless tuners mounted to the wooden body. There's no tailpiece - the string angle behind the bridge is taken care of by the tuner placement. Plenty of pictures at my web site www.tranjo.com.

Sam

How did you do the tuners for your headless neck?


Jan 23, 2020 - 2:13 PM

47 posts since 11/14/2018

Here is the link to the tuners I'm making. I adapted this plan for 5 levers instead of 6.
The brass bracket is really difficult to make to exact dimensions using simple DIY home workshop tools. Mine came out pretty good but it is about 2 mm long. I will compenste for that with either two extra washers or will make the 5 levers slightly wider. I think the other parts will be easier to make. You can easily cut aluminum with carbide tipped blades and woodworking tools if you are careful. I haven't decided whether to use the ultrafine tuning screws or just go with 8-32 screws from the hardware store. The ultrafine 100 tpi screws are around 10 times the cost.

buildingtheergonomicguitar.com...op-3a.pdf

Jan 23, 2020 - 2:26:46 PM

47 posts since 11/14/2018

sdfarris Thanks for the comment on the curly maple neck reinforced with carbon fiber rods. I had considered something like that if I go with a wood neck. Do you use a seperate fretboard? If so what wood do you use for the fret board.

One of the lightest woods considering the strength to weight ratio is cedar or cypress. Either of those is really soft though and would get beaten up easily. That said, reinforced with carbon fiber rods a cedar neck would do the job if you used a harder wood for the fretboard.

I have always liked curly maple and the cedar would probably not save a lot of weight on such a small item but ounces count when backpacking.

Edited by - 98v70dad on 01/23/2020 14:28:51

Jan 23, 2020 - 2:59:02 PM

1827 posts since 2/28/2003

quote:
Originally posted by 98v70dad

sdfarris Thanks for the comment on the curly maple neck reinforced with carbon fiber rods. I had considered something like that if I go with a wood neck. Do you use a seperate fretboard? If so what wood do you use for the fret board.

One of the lightest woods considering the strength to weight ratio is cedar or cypress. Either of those is really soft though and would get beaten up easily. That said, reinforced with carbon fiber rods a cedar neck would do the job if you used a harder wood for the fretboard.

I have always liked curly maple and the cedar would probably not save a lot of weight on such a small item but ounces count when backpacking.


Yes, I've always used a separate fretboard made of either hard maple, ebony, or rosewood. My Tranjos are built by a professional luthier who uses a CNC machine to perfectly cut the neck shape and fret slots. I had him send me a prefretted fingerboard and slotted and shaped neck, and I epoxied the CF rods into the slot and then attached the fingerboard. You might consider bamboo laminate for your neck - it's very light and extremely durable. You could cut up a bamboo cutting board or some bamboo flooring to make a neck blank. We used to make Tranjo Express body plates out of bamboo plywood, but it's expensive (several hundred dollars for a 1/2" x 4' x 8' sheet) and not that easy to get, so we switched to birch plywood.

Sam

Jan 23, 2020 - 3:24:13 PM

47 posts since 11/14/2018

sdfarris the bamboo is a great suggestion. I hadn't thought about that.

Jan 24, 2020 - 7:24:02 AM

47 posts since 11/14/2018

quote:
Originally posted by G Edward Porgie

I'd like to see what you come up with for your tuners. I've sometimes wondered why banjos and other string instruments are tuned from the peghead, which can throw the instrument out of balance.


Here is a link to a pdf that I based my tuner on.  I'm not done with making my tuner but I've sourced some parts and made  the brass bracket.  Many of the parts can be gotten at a hardware store for much cheaper than the suggested sources.  The pdf is an excellent resource though.  I've modified the idea to meet my needs (5 tuners) and reduce the cost.
buildingtheergonomicguitar.com...op-3a.pdf

Jan 24, 2020 - 8:23:55 AM

1827 posts since 2/28/2003

Speaking of tuners, I forgot to mention that my lightest custom Tranjo used Gotoh Stealth tuners instead of the Steinbergers. They work very well and only weigh 12 grams each - 60 grams (2.1 oz) for 5. You might consider them if your custom tailpiece tuner doesn't work out or is heavier than you want.

Gotoh Stealth Tuners

Sam

Jan 24, 2020 - 10:59:50 AM

47 posts since 11/14/2018

sdfarris Thanks for the idea. Those are really nice tuners.

I may not have mentioned it but my inspiration for this project was 1) backpacking - my favorite hobby and 2) panjo or old time open back banjo made from repurposed stuff I had around the house (junk I can get for free). The carbon fiber neck was/is way off regarding inspiration 2) but right on for 1). I'm probably not going to go with the carbon fiber neck because it isn't really necessary and its not stuff I have laying around in my workshop.

I have almost everything I need to construct the banjo and have spent somewhere between $10 and $15. I'm not shooting for a fine instrument - just something that works.

Feb 22, 2020 - 10:33:14 AM

1827 posts since 2/28/2003

This discussion got me interested in some more experimentation. I'm going ahead with a new model - the Tranjo Express III XLT - and I'm trying to get the final weight down to 2 pounds or less. I put all the parts (except for the Gotoh Stealth tuners and the bolts) on the scale, and it came at 1 lb 13.8 oz. The tuners weigh 2.1 oz total, and I'll use aluminum bolts which I estimate will weigh about 0.4 oz total. That will put me an ounce or two over 2 pounds, so I'll probably drill some holes in the body plate to shave more weight.


The neck by itself came in a lot lighter than I remembered - 11.2 oz. I'll cut that carbon fiber bar in half to glue into the truss rod slot.

XLT neck parts

By comparison, the same neck with a Stewart McDonald Hot Rod weighs just over 1 pound.

Sam Farris

Feb 22, 2020 - 3:27:25 PM

7531 posts since 1/7/2005

I believe Scott Vestal's "Stealth" banjo has a carbon fiber neck.

DD

Feb 22, 2020 - 3:59 PM
Players Union Member

rudy

USA

14980 posts since 3/27/2004

quote:
Originally posted by 98v70dad
quote:
Originally posted by G Edward Porgie

I'd like to see what you come up with for your tuners. I've sometimes wondered why banjos and other string instruments are tuned from the peghead, which can throw the instrument out of balance.


Here is a link to a pdf that I based my tuner on.  I'm not done with making my tuner but I've sourced some parts and made  the brass bracket.  Many of the parts can be gotten at a hardware store for much cheaper than the suggested sources.  The pdf is an excellent resource though.  I've modified the idea to meet my needs (5 tuners) and reduce the cost.
buildingtheergonomicguitar.com...op-3a.pdf


You might pick up some ideas from the "Cane Jo" Walking Stick Banjo I posted a few years back.  I made it specifically as a walking cane that would double as a relatively quiet instrument that could be used without running off the wildlife!  wink

"Cane Jo" A Walking Stick Banjo

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