Hey folks,
I’m new here as a user (although I’ve read a lot of topics in the past), and now I need more specific information. I hope someone here can help me out.
I have the opportunity to use some beautiful wood from my parents-in-law to build a new instrument. I’ve already built a grain measure banjo a few years ago.
Now I’m asking myself whether I should build the neck from a single piece or laminate two pieces together, as described by user Ken LeVan.
If I choose the one-piece option, which grain orientation do I need? Should it be flatsawn or quartersawn? To get more specific, which variations were used in old banjos like the Fairbanks Whyte Laydie?
The wood I’m referring to is birch. I know it’s quite unusual for building a banjo or for other luthier projects, but it’s local, coming from my parents-in-law’s property. It would be wonderful to give their beloved trees a new purpose in an instrument played by a professional musician.
Best greetings from Bamberg (Germany),
Steve
The two-piece version resists the warping that might happen with the same wood as one piece. (You likely know that but others might not.)
I don't know about banjo history, but builders huge and small that I know use quarter sawn. High end violin makers are fanatical about that. (They can be because they command high prices, and the size of the necks is tiny compared to banjos.) In particular, every neck blank shows grain going absolutely vertically -- from fingerboard to the bottom of the heal. In contrast, the accompanying photo shows four Deering one-piece Goodtime necks, which are all nominally from quarter sawn. (Note that the heel block is pieced to the main neck piece.)
That can get a little confusing depending how you use your lumber.
Quarter sawn will have the annual rings oriented from face to face rather than edge to edge.
So guitar makers cut their necks with the fingerboard on the lumber face. Which is why they want quarter sawn lumber.
But when making banjo necks, whether you choose to laminate two pieces of 6/4, or cut a blank from on piece of 8/4 and glue "ears" on the headstock, the fingerboard is on the original lumber edge.
So if you've got a piece of flatsawn turned on its edge, then the annual ring orientation is as desired (perpendicular to the fingerboard).
Although, I once asked Richie Dotson about this because he seemed to have some neck blanks with rift sawn orientation; He basically said if the wood is stabilized, it doesn't matter.
A further speculative comment as to the why's: Wood stiffness is highly anisotropic with respect to the three obvious growing directions. Once you've cut your one piece into two and glued them back-to-back (e.g., as described by the late-great Mr. LeVan), you've got something resistant to twist and sideways warp. The tone of the instrument is impacted by the stiffness with respect to the natural banjo axes. So, just as different wood species produce very slightly but discernibly different sounds, the same wood will show some variation for different grain orientations.
In another, recent thread, I described "better" as being closer to what your Momma played when you were young. Every string instrument made of wood, even with the same design and species, will sound different. If carefully made, I am certain that the above-described birch will sound wonderful -- however the wood is milled.
(I forgot to add the shameless self-promotion to my first reply. The photo comes from Four Banjo Necks and One Pot.)
Sorry if the way I phrase things is confusing.
Here is a picture of 8/4 flat sawn lumber.
When turned sideways, the annual rings are oriented perpendicular to the fingerboard surface.
For the same reason that plywood is stable, a banjo neck made of several pieces of wood is sure to be more stable than a single piece neck. For sure, quartersawn wood is an essential ingredient, and if you add a center line of wood between the two halves of the neck that will increase the stability. If you add purfling and edge binding to the fingerboard that makes the neck sort of a very complex piece of plywood. Add an ebony or rosewood fingerboard and a truss rod and you should have a neck that will withstand the apocalypse.
All this is the result of many years of dealing with lots of old and newer banjos. The neck of my main banjo - a thirty-five year old custom Deering Calico that has been heavily played every day - has all the neck characteristics I described above, and the neck has never needed any adjustment or repair in all these years. No seasonal adjustments, no warping, holds its perfect relief year after year.
I don't know anything about the stability and moisture characteristics of birch wood; other more knowledgeable folks might know about that particular wood; worth checking out before starting the build.
Even more important than grain orientation is dryness.
Don’t assume wood that’s down for a “few years” is appropriately seasoned.
Don’t ask how I know this.
Another big benefit to building laminated necks is you have the center line to index from. Helps keep everything straight when you start shaping.
A luthier friend uses the same approach as shown by Douglas Berry, except that he uses a flat sawn piece half as thick and twice as long. He cuts it in half and folds it back on itself so that the end grains are perpendicular to the fretboard and mirror imaged.
Seems that a truss / steel / carbon fiber rod should be considered in this discussion somehow. Its not just the wood grain, right?
