Need input on Carving Banjo Necks: Initial Design & Twea

[Rcnewcomb]

(Also posted on the Shopbot forum...)
I've decided that I want to build some banjos and I'd appreciate some input on the best way to get the initial cutting file for the neck and how to be able to fine tune the design for efficient machining and proper playability.

Necks are typically carved out of a block of wood that is 26"x2"x3". It is usually a glue-up of maple, mahogany, or walnut.

Since I currently have no 3D design software it looks like my choices are to pay someone to:
1) scan a physical neck that I provide
2) create the neck file based on blueprints that I have

Which method would provide a better file for tweaking later?

If you were in my position would you go with option 1 or 2?

(James B, if you are looking at this what would you need to create this type of design?)

Additional information:
I'll probably use Cut3D for toolpathing. Probably a 1/2" ballnose would work as the carving bit. I'd prefer a design that would only need to be carved on the front and back, rather than having to machine 4 sides. Final shaping would be done using a spindle sander so I can do some of the undercuts and sand out stepover marks.

[CRFultz]

I watched "Made in America" yesterday afternoon...They went to the Deering plant in Spring Valley.
Most of there necks were Sugar maple....They formed the neck using a bandsaw and then glued on the
two pieces at the top. It would seem to me that the basic shape would not require a CNC to fabricate.
If the shape could be cut out and then sanded then a CNC used to get the frets and the keys placed correctly...and therefore use VCP for the software.
Inlays and such could also be accomplished using VCP.

Maybe a jig on the CNC could be designed to get the neck placement on a 2d plane.

What I'm getting at, do you need a 3D file of the neck?

I know nothing about musical insturments....but I am looking to make a stringed instrument, using my machine, of some sort just so I can say I did.
By looking at the Deering prices I can see where one would want to construct a few.

[CRFultz]

These may or may not be of any interest but....

[dighsx]

Where the cnc work would come in real handy on making necks is on the fret board. Doing inlays becomes a lot easier and also laying out the fret locations and cutting them for fret wire is a snap.

Another place you may want to think about some 3D work is the back of the bell. I could some cool carvings or inlays there. But depending on if you make a flat or arched bell back it could get tricky.

I've done some instrument work and here are a few tips I've learned. (I'm not trying to discourage you from making them):
- It helps a lot if you play the instrument you're trying to make
- Find a good book or two on the construction of the instrument and by careful attention to tuning it as you build it. (sound bars, resonator, etc)
- Keep a build log and measurements of all tuned parts
- It's easy to make an ok to good instrument, it takes a long time to make a great instrument
- Once you make a few that are good you realize how crappy some "professional" (read factory made) ones are
- Let as many people as you can play the first few you make and listen to what they tell you. If you can find a few really good players their feedback can really pay off in the end.
- Buy a digital tuner

Good luck and keep us posted on your efforts. I've repaired a few mandolins and guitars and I'm just starting a mandolin build for my brother-inlaw. So I've been down this road a couple of times.

[CRFultz]

Jay is there anything that you don't dabble in?

I don't want to step on Randall's thread...so lets discuss Musical insturments in the general forum.

I am VERY interested in building a Hammered Dulcimer.

[dighsx]

There are just to many interesting things and not enough time if you ask me. I drive my wife nuts with all my crazy projects.

I started a new thread on instrument building: http://vectric.com/forum/viewtopic.php?p=6924#6924

Ok Randall you can have your thread back. hehe

[doglaw]

I am in a very similar situation. I decided to take a stab at building violins and I likewise wanted to cnc the necks. I ended up downloading Wings, some modeling software, and Blender (all free 3d design packages) and evaluating them. Having never done any 3d design before, it is a daunting task. Because Blender looked to be the most supported, most professional package, I decided to go with it. I downloaded and watched the video tutorials (8 of them) and also did the modeling tutorial in the manual. Last Thursday, I started designing the neck and after about 16 hours of design work I was cutting a prototype on the Shopbot. The process is not as daunting as I once thought it was and would highly recommend Blender to anyone who wants a good - solid - free 3d package.