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Comment by Madurobob on January 16, 2012 at 10:06am

I strung up All Walnut #2 a few days ago.  Sounds goods, plays good, and no issues with the neck bowing so far.  I'm convinced the issue with #1 was grain orientation.

Also, FWIW, the AW #1 has not bowed anymore since the original stringing.  The action is a little high towards the saddle, but I can shave the saddle down to compensate.

As for sound, I think it could be better.  But, I'm not sure if its the relatively large walnut bracing inside the box, or something to do with the boxes themselves, or something else.  I have several more necks ready to play with, so I'll try a couple of different boxes.

Comment by Madurobob on January 10, 2012 at 7:50am

OK, I'm mid-way through All Walnut #2.  Much beefier bracing inside the box, and a bit more care in selecting neck stock with a better grain orientation.  I'll string it in a couple of days I think, but it already feels much stronger than #1 when I try to bend it.

A couple of quick pics.  First, a quick view of the bracing.  The end pieces are rough cut 1X1s. Then, another 1" piece is scabbed onto the back of the neck where it passes through the box.  The end pieces are cut out to hold the neck firmly to the box top, and they are glued to the neck and box and hold everything firmly in place.
I forgot to take a pic of the neck before I glued it in, so I drew a pic of the basic construction:

Finally, the top of the box, as of yet unadorned with guitar-type stuff and no fingerboard yet.

Comment by Madurobob on January 5, 2012 at 4:01am

Just to be clear on the grain direction issue:

The first board I pulled out to make necks from is a 6/4 board (will plane down to 1.5 inches w/o almost no waste) about a foot wide and 8 feet long and milled "through and through" from somewhere about midway from the middle of the tree.  So, looking at the end of the board you can see the curvature of the growth rings.  The rings run at about a 30 degree angle to the cut of the board on the outsides and trending towards a 90 degree angle as you move towards the middle.  In the middle of the board the growth rings run all but parallel to the cut of the board.

I cut a piece off that board the length of my necks and then ripped that down to pieces just over 1" wide.  Then, I ripped those into two pieces, one 3/4" and one 1/4" so I had a neck and a fingerboard from the same piece of wood.  The problem was, I think, that the first neck I chose to use was from the middle of the board where the growth rings run almost parallel - a poor angle in terms of bending strength.

Comment by Madurobob on January 4, 2012 at 10:18am

Wade, I think you may have hit the nail on the head.  I cut my first few test necks just like I have been cutting my oak necks that have had no bending problems.  But, it seems obvious looking more closely at the grain that it would resist bending a lot more if I turned the neck 90 degrees.  I'll need to pay more attention to that when I bring the next board in for cutting.

And I agree on the oil: walnut with hand rubbed oil is, to me, about a pretty as wood can get.  I built a walnut  humidor/beside table for a friend of mine a few years back and gave it to him unfinished at his request.  Later, he invited me to his house to show it off and I had to just bite my tongue and grin as he showed me that wonderful piece of furniture completely slathered with polyurethane.  Ugh.

Anyway, its cold here and my shop is not heated but for a burner on a propane cylinder.  I'll get back to testing walnut necks soon when it warms up a little.  But, as I said, I think grain orientation is the problem with my first build.

Comment by Wade on January 3, 2012 at 4:30pm

I love walnut. I made a few dulcimer cbgs and really enjoyed working with this wood- like the smell too. Finishes really well with tung oil. From my experience as long as the grain is perpendicular to the fretboard no worries.

Comment by Madurobob on January 2, 2012 at 12:28pm

If guitar #2 isn't much better with just a bit more bracing inside the box, then I'm going to look into steel reinforcement.  The walnut neck is too pretty to completely abandon.  And, if guitar #1 doesn't get any worse then I can find a way to make it work.  Trouble really happens when it just keeps warping more over time.

What I've done before is simply rout out a 1/4" wide and 1/4" deep box channel in the neck and drop in a length of 1/4" square steel rod before gluing on the finger board.  Its not adjustable, but adds quite a bit of bending strength.  But, I'm a big fan of simple and want to avoid any routing and steel if possible.

Comment by Chris Thomas on January 2, 2012 at 11:41am

Hi mate, hard to tell from the pics but a real shame that it did not work out perfect. A truss rod could be installed inside but would add a lot of weight, maybe a 4mm threaded rod with a couple of nuts to pull back against a couple of aluminium brackets might just do it, as I have no experience as yet it's just an idea, shame to waste all that work though. Nice job all the same, a real shame but something to overcome, keep us all posted on progress as I am sure were all on tenterhooks with this one, well I am mate. Chris. :)

Comment by Madurobob on January 2, 2012 at 11:19am

Should have mentioned, I checked two of my oak necked guitars with the same strings and tuning, under tension for about the same amount of time.  One was perfectly flat, one had about 1/8th inch deflection.  Both were perfectly flat on the frets (thus the bend is occurring inside the box).

Comment by Madurobob on January 2, 2012 at 11:10am

OK, a couple of pics.  This is what the neck deflection looks like after two days at tension.  Strings are .045, .035 & .026 inch and tuned to GDG.

 

First, with the strings slack:

Then in tune:

Where the straight edge reaches the nut perfectly flat would be flush with the top of the neck/bottom of the fingerboard.  As it is the neck has bent about 1/4 with the strings slack and slightly more when under tension.

I ran the straight edge over the frets and there is some warping evident there, but not enough to impact playability.  So, the bulk of the warping must be going on inside the box where the neck is thinner.  I'm going to leave this one as is for a few more days to see if it gets worse.  In the meantime I'll build another with a bit more bracing inside the box to see how much that helps.

Comment by Dan Sleep on January 1, 2012 at 1:19pm

Bob, too bad you aren't closer to Camp Lejeune. I would take you up on that next time I am down that way!!

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