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Permalink Reply by Andy Eight Spades CBG on July 21, 2011 at 12:22pm

Just cut down about 1/8" on the top of the neck under the soundboard except on the very ends.  So really the top is just resting on a small section at the nut side and tail side, and the middle is free to vibrate.  Some people brace the neck in from the bottom and leave the top free all together.  There is no set way just find what works best for you.

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Permalink Reply by Rand Moore on July 21, 2011 at 12:43pm

Hi Shawn Jennings,

 

You definitely want to have the sound board free to vibrate. In order to do that, you need to cut out maybe 1/4" worth of wood from the lower end of you neck where it passes under the sound board. It is okay to have maybe a 1/2" overlap at the top where the neck meets the box, and where it leaves the box. If you cut the holes for your box down toward the middle of the box, then definitely your action will be very high. You want to mount the neck (or neck and fretboard) such that the fretboard is level with the soundboard (or at least maybe slightly above the sound board. If you cut your box already, here is a fix you can try (I'll draw a picture):

 

 

This may shorten your neck and scale length. To prevent that, see if you have another piece of wood you can use for the neck-thru and heel joint.

 

Hope this helps.

-Rand.

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Permalink Reply by Seaman Jay on July 21, 2011 at 9:18pm

nice picture, Rand

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Permalink Reply by Shawn Jennings on July 22, 2011 at 2:46am

Thank you very much, thats exactly what I needed, The build plans on the website were a little confusing when it came this subject. thanks again!

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Permalink Reply by Rand Moore on July 22, 2011 at 4:37am

Hi Shawn,

Happy to help out.

-Rand.

 

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Permalink Reply by Skeesix on July 22, 2011 at 6:12am

How long do you make the board overlap for the "fix" design so that it's a strong joint?

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Permalink Reply by Rand Moore on July 22, 2011 at 8:52am

At least 3 inches. Four if you are worried. Now tell me some secrets for winding mag pups ;-)

-Rand.

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Permalink Reply by Shawn Jennings on July 22, 2011 at 8:58am

So for my second build what are your suggestions for neck placement so Im not cutting into the middle of the box and having to "fix" the high action. I was thinking notching out the part of the neck that is in the body so it doesn't touch the lid

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Permalink Reply by Seaman Jay on July 22, 2011 at 9:31am

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...)

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Permalink Reply by Roadkill a.k.a. John Maw on July 22, 2011 at 10:04am

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.

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Permalink Reply by Seaman Jay on July 22, 2011 at 10:19am

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.

 

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Permalink Reply by Rand Moore on July 22, 2011 at 11:29am

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:

Most of my necks are laminated, as shown above. The main reason is that I don't have access to good building materials in China, so I glue together "trim wood" to build up my necks. On this early version, you can see I laid the slats horizontal, which makes it easy to leave off a piece for the sound board hollow, and even re-strengthen the neck by adding another board beneath. I could do the same for the headstock. However, my last 5 or 6 necks were built with these slats standing on their side is a "vertical" orientation (turned 90 degrees from what's shown here) to make the neck even stronger. With this "vertical orientation", I have to cut out some wood for the sound board hollow, and for the headstock, but I'm willing to do it for the stronger neck.

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.

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