Truss rod trench

[nvanlaar]

Does anyone cut the trench into the backside of the neck and fill with another decorative wood? I have not seen it in mandolins, but have seen it in several electric guitars. Is there a reason for not doing this? Strength or mostly aesthetics? I have always liked the look, but especially the hand-rubbed, silk-smooth necks on some guitars.

Thanks,
Nick

[Jim Hilburn]

When Leo Fender and his staff designed the Broadcaster, they decided to use a single plank of slabcut maple for the neck. The fingerboard wasn't a separate board, the top of the neckblank was radiused and the frets were cut right into it. The only way to install a rod was through the back.
When they decided to start using rosewood boards in the late 50's, there was no need to install them from the back anymore and they went to the more conventional way of doing it.

[thistle3585]

I just recently did it because I discovered a flaw in the wood when carving it so I decided to give it a try. It wasn't difficult but I wouldn't do it again. If you want the contrasting strip then glue up the neck that way.

[nvanlaar]

Yeah, that's kind of what I have been thinking about - a solid maple neck with no rosewood/ebony fret board. Just for something different. Aside from the fret board becoming dirty with use is there any other drawbacks? Would a solid maple neck even need a truss rod (on a mandolin)?

BTW- I have seen a few other manufacturers do this as well, Ibanez comes to mind. That or maybe it was just a thin inlay for looks. I don't recall, but I do remember the stripe of brown down the back of the neck.

Follow up question- Which neck-joint is stronger? Dovetail or Siminoff "V"?

Cheers,
Nick

[pops1]

Usually guitars with a maple fretboard are brighter sounding than ones with rosewood or ebony. Seems to me a mandolin would be brighter too.

[Bill Snyder]

If you see a stripe down the backside of a neck it is probably a three piece (or more) neck.
You can certainly find mandolin necks like that.

[nvanlaar]

If you see a stripe down the backside of a neck it is probably a three piece (or more) neck.

Not always. The stripes I am thinking about began and ended in the neck with half round ends (they were not the entire length of the neck). They clearly were not a part of a laminate. Jim is spot on.

Now that the multi-strip laminated necks have been brought up, that is an idea I hadn't thought of. Perhaps add some thin strips of white ash to really make the walnut(?) pop.

[Bill Snyder]

Yes, I knew that.

[nvanlaar]

With the added structure of the lamination is a truss rod needed? It seems to me that a laminated neck would be very stiff.

[Lefty Luthier]

Usually guitars with a maple fretboard are brighter sounding than ones with rosewood or ebony. Seems to me a mandolin would be brighter too.

Here is a shot of an oldie that I made with a maple fretboard. Can't say that there was much difference in sound quality. Main problem with maple fretboards is that they tend to get scratched more easily and should be protected with a coat of varnish which then makes the fretboard more difficult to keep looking good.

[Michael Lewis]

Adding glue joints in a neck do not make it stronger. The strength of a neck comes from the selection of material, shape, and size. There are mandolin necks with no reinforcement, but usually they are the shorter 12 fret variety. If you are going to make a long (15 fret) or thin neck it will need reinforcement.

[Rob Grant]

Lami', how I loves ya', my dear 'ol lami' <G>

I've got a strong affection for three-piece necks. Like the "glulams" used in building construction, they are stronger and more stable then a one-piece neck. I make a stainless steel truss rod which I install in my three-piece necks. I've never had to adjust one of these rods to correct a problem. In future I'll probably eliminate the weighty rod and replace it with carbon fibre.

One added advantage to the three-piece neck is that you can use the center stripe as a reference point when carving the neck.

Below is an image of several laminated neck blanks and a finished F4. The lighter timber is Queensland "Maple" (Flindersia) with darker Cooktown Ironwood (Erythrophleum) as a centre strip.

[nvanlaar]

Like the "glulams" used in building construction, they are stronger and more stable then a one-piece neck.
This is what I was thinking. I would be willing to bet that if a person took a solid blank, sawed it in half and glued it back together it would be stronger/stiffer in the direction directly inline with the seam, especially if one half was flipped or turned 180 degrees so the grain was opposite on the pieces.

Thanks for the pics everybody. It gives me inspiration. Now if only my wallet were a little fatter...

[Martyweir]

Lami', how I loves ya', my dear 'ol lami' <G>

I've got a strong affection for three-piece necks. Like the "glulams" used in building construction, they are stronger and more stable then a one-piece neck. I make a stainless steel truss rod which I install in my three-piece necks. I've never had to adjust one of these rods to correct a problem. In future I'll probably eliminate the weighty rod and replace it with carbon fibre.

One added advantage to the three-piece neck is that you can use the center stripe as a reference point when carving the neck.

Below is an image of several laminated neck blanks and a finished F4. The lighter timber is Queensland "Maple" (Flindersia) with darker Cooktown Ironwood (Erythrophleum) as a centre strip.

Wow Rob - nice looking back on that one! Is that also Queensland "Maple"? Very cool...

[Rob Grant]

Martyweir wrote:
"Wow Rob - nice looking back on that one! Is that also Queensland "Maple"?"

The back is what we call "black walnut." It's not really a walnut at all, but one of our local rainforest timbers that the early pioneers thought resembled the black walnut of the norther hemisphere.

The butts of these trees (where the best figure is found) often contains large amounts of silica. Cutting our black walnut with a bandsaw often results in a red hot, totally destroyed blade. I usually cut my walnut back wedges with a handsaw. The smell of the green timber when you're cutting it is very memorable. It has the odor of a "technicolour yawn" ("Oz speak" for throwing up).<g>