Hello, I just started to build my first CBG yesterday and after watching a bunch of different videos and reading some different plans I have a few questions about the placement of the neck for my next build.
Does it matter if the neck is touching the top of the box. I built a through body neck and I read somewhere that if the neck is touching the sound board it wont sound that good. The box I used had a lid that didn't sit flush on top of the bottom part of the box, it was not as wide as the bottom and when closed sat flush in between the lower half, So I cut a hole in the middle of the bottom half of the box and ran the neck straight through that way, but since the neck is so far away from the top of the box the action is going to be really high. I apologize for not providing pictures as it is at my father in laws house drying from the polyurathne coat.
Basically I was wonder how people treat the neck and the soundboard of their boxes and weather or not they cut holes in the top and bottom of the box and allow the top to rest on the neck or if people take actions to prevent the top of the box from resting on the neck.
Thanks!
Replies
Hi Shawn,
You need to decide on what scale length you want before you decide on the neck length. Different people have different preferences for scale length. Some like them short, others long. When you make them very short you end up with a Cigar Box Ukulele, when you make them very long, you end up with a Cigar Box Bass. Cigar box guitars usually range from 22 to 26 inches with 24 to 26 being most common as that's what most common with real full size guitars. I, myself prefer 20" scales, but then the instruments I build all have diatonic scales and are what I call "stick dulcimers". What ever scale length you decide upon, be aware that part of the scale length will be located over the cigar box, and part over the neck. Usually, the bridge is placed something like 2/3s the way across the cigar box to give the player enough room over the sound board to pick and strum. So, if your box is 9" long, six inches of that length will be part of the scale length. If you decide on a 24" scale, minus 6" for the area over the sound board, that leaves 18" of scale that has to be covered by the neck. A five inch headstock is pretty common, and if you are doing a neck through design, maybe 1" or 2" on the tail end of the neck, what you will need is 5" + 18" + 9" + 2" or 34", which as you can see from above is what Dan Sleep typically uses.
On my instruments, I build up the neck using 6 or 7 slats of cherry trim wood that is sold in lengths of 2.2 meters. If I am careful, then that means I can get 3 slats of 73.3cm from one 2.2 meters of wood. So, I'll need at least two 2.2 meter lengths of cherry trim wood (but I usually buy a bit more and so may but on a 7th slat). So, given a 73.3cm (about 28.75") neck and head length limit, I first allocate 4.5" to 5" for the headstock, then the rest for the neck. I have to play around with the numbers a bit because the length of the cigar box varies, and so the portion of the scale length of the neck verses the portion of the scale length over the box varies. I do save some on neck length by making my instruments "neck-almost-thur" builds. This is where the tail end of the neck does not penetrate the tail end side of the cigar box. Instead, the neck butts up against the side and is secured to it with a couple wood screws. So, give 24.75" of wood, 4.5" to 5" for the head, my necks tend to be 23.75" to 24.25" in length and the amount of exposed neck (as opposed to the part under the sound board) varies depending on cigar box size.
So, when I make my neck, I do my measurements and calculations, cut a series of perpendicular cuts into the part of the neck that will be under the soundboard to create my neck hollow. This series of cuts is made with a small hack saw and the cuts are about 3/8" deep and each cut is about 1/4" apart. After making all the cuts, I use a chisel to wedge down into the cuts, snap the piece of wood out of the hollow. I repeat this until all the wood has been removed from the hollow. The resulting hollow is rough, so I file and sand it down till it looks half decent and get on with the rest of the build. I use a similar process to form my headstock. With the headstock, you have to design it around the tuners you plan to use. I often use those sets of 1x3 guitar tuners, and they require at least 3/4 inch of wood around then to be screwed down properly. I am also concerned about something called the string break angle of the strings coming over the nut. For these two reason, I cut about 1/4" off the top face side of my headstock, and then I slot the head stock (by drilling a series of holes about 4" in length and redrilling then with larger and larger drill bits untill the start to break through. Then I use chisels, files and sand paper to break out the remaining waste wood and to clean it up. I then drill 3 holes for the 1x3 set of tuners, making sure to measure and mark my wood so the cuts will be accurate. Once I'm done, my headstock looks like this:
-Rand.
It needs to be long enough to reach the box, of course.
Seriously though...I make the headstock about 5 inches, and usually make the scale 24 inches. My necks overall are typically 34 inches or so.
Rand Moore said:
Yeah. That's a great drawing.
-Rand.
I do it pretty much exactly like this:
And I make sure the bridge sits over the part that is recessed so the lid can vibrate the most.
Hi Shawn,
I don't really have a good photo of how I shape my necks and allow space for the sound board to vibrate (a place I call the "sound board hollow"), but I do have this photo of an early laminated neck that shows this "hollow" area. Here it is:
When I cut the hollow, I take a mini hack saw (or similar saw) and cut a series of lines across the grain of the neck. Each slot is cut maybe 3/16" into the neck. Each slot is separated by maybe 1/4" of wood, and after making enough slots to cover the length of the sound board hollow, I then use a chisel to snap and pry out the little pieces of wood. The resulting hollow is rough, so I use a wood rasp and sand paper to make it relatively smooth. Because this area will be hidden by the sound board, I usually don't take the time to make it as pretty as the rest of the neck, but I do put a few coats of polyurethane on it and the rest of the neck to protect the wood.
When installed within a cigar box, I slot the sides of the cigar box in such a way that the top side of my neck is level with the sound board. If I use a fretboard, I might even lower it a bit deeper into the sound box. On my more recent builds I have been making the neck side of the cigar box a little deeper, and I glue on a little bit of scrap wood (1.5" x 3cm x 0.5cm) to the inside of the tail end of the cigar box to make a little shelf to receive the tail end of the neck; making sure to raise the tail end of the neck relative to where the neck enters the cigar box. This forces the neck downward a few degrees and lowers the action for the strings. The neck is usually glue in place and sometimes re-enforced with a screw, especially on the tail end of the neck.
If you look around on the CBN website, I sure you will be able to find similar photos of how other builder do it.
-Rand.
Well, I had "some thoughts", there's much more space under the strings when you're playing an upright or electric bass. I tried and it seems to be enough for me - YMMV.
It's the way Kazakh dombras' necks are connected with the body - one can actually use the soundboard as an extension to the fretboard. Not really an option with the small box I used for my CBG...
The neck angle -- I love the way the fingerboard of a double bass or cello "misses" the body of the instrument by few inches.
Never played a guitar configured that way, but want to give it a try -- someday.
Hi Rafal.
My first instrument started out with the fretboard level with the top of the box as you describe. I didn't like it as there didn't seem to be enough room between the strings and the box. Of course it depends on a number of other factors. Personal taste, how high you like the action and to some extent weather you like the neck angled back a bit or not, although the last point will make only a small difference unless the neck angle is silly.
I discussed this on the forums at the time and quite a few people were saying that they liked to have the fretboard higher. I do too. I make mine so that the neck without fretboard is just above the level of the box and then add a substantial fretboard. Weather you have frets or not also make a difference as this is in effect an added thickness to the fretboard when considering the action height.
Some well respected makers keep the fretboard flush with the lid. Others don't (do I hear someone saying "no rules").
Returning to the mention of neck angle that is something that I don't think I have seen mentioned here. I prefer to angle the neck back a bit. It helps raise the bridge and give a greater angle at the bridge/saddle, which means more pressure on the bridge (which I take to be helpful).
Just a couple of thoughts.
you don't have to notch out/carve anything. Just install the neck not directly below the soundboard, but a bit lower (say "thickness of the fingerboard lower") and glue the fingerboard onto it. This way you'll have a "free-to-vibrate soundboard" and a fingerboard lined up nicely with the soundboard. Check my pictures if you're not sure what I'm talking about. It was quite intuitive solution, but I'm gonna to use it again (and again, and...)
-
1
-
2
of 2 Next