Solving a neck problem

Construction and repair of Classical Guitar and related instruments
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attila57
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Solving a neck problem

Post by attila57 » Mon Mar 13, 2017 8:00 pm

Hi,

I've come across a guitar that has an excessively sloping neck. Therefore, the action at the 12th fret is too high (7 mm @ E6). First I wanted to shim the fingerboard, then I thought of a better solution.
I removed the fretboard with cc. alcohol, as it'd been glued on with hide glue.
I found that the neck itself is not only too sloping, but too flexible, too. So I decided to make it more stiff by routing a channel into it, and gluing a hardwood piece in it.
Right now I've just finished the routing job. This is how it looks:
Routing_the_neck.JPG
I'm going to glue in a piece of ironwood. Afterwards, I'm going to prepare a new fretboard with a thicker soundhole end to compensate for the excessively sloping neck.
Any comments?
Attila
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Music to hear, why hear'st thou music sadly?
Sweets with sweets war not, joy delights in joy...

William Shakespeare, Sonnet 8

Paul Micheletti
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Re: Solving a neck problem

Post by Paul Micheletti » Mon Mar 13, 2017 8:42 pm

That should work. I inlay a stick of quartersawn hard maple into every neck I make. I had a piece of Spanish Cedar that I could easily flex with my hands. The hardwood inlay stabilized the neck nicely.

I've also used carbon fiber reinforcement beams in the past, but I prefer hardwood. Carbon fiber is pretty much instant death to any tool edge so you have to set it down too low as it cannot be planed. You can set hardwood proud and plane it to the level of the neck later as I prefer.

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James Lister
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Re: Solving a neck problem

Post by James Lister » Mon Mar 13, 2017 10:20 pm

Paul Micheletti wrote:I've also used carbon fiber reinforcement beams in the past, but I prefer hardwood. Carbon fiber is pretty much instant death to any tool edge so you have to set it down too low as it cannot be planed. You can set hardwood proud and plane it to the level of the neck later as I prefer.
There's a simple solution to that. Glue (epoxy) a piece of hardwood to the top of the carbon fiber (about 3mm), then rout your channel 1 - 1.5mm deeper than the carbon fiber + hardwood. Glue the bar in, then plane off the excess hardwood.

These days I also glue a strip of hardwood to the side of the CF - it's much easier to plane this down to get a perfect fit in the channel than it is to adjust the channel with the router to fit the CF bar.

CF is much stiffer than maple (or ebony - not sure about ironwood)

James
James Lister, luthier, Sheffield UK

Marshall Dixon
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Re: Solving a neck problem

Post by Marshall Dixon » Tue Mar 14, 2017 12:10 am

I used ebony and rosewood, but CF for the most part, insetting it just slightly with a wood fillet on top as mentioned above. An old file with a chisel edge ground into the end is what I use on any edge dulling material.

How about using aluminum? - it's cheap and readily available.

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attila57
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Re: Solving a neck problem

Post by attila57 » Tue Mar 14, 2017 9:39 pm

James Lister wrote:
...CF is much stiffer than maple (or ebony - not sure about ironwood)

James
Ironwood is very stiff indeed. I got a quartersawn piece that I cut in two halves with a band saw, 6 & 8 mm thickness. The rings' are parallel with the longer side of their cross section, so in the neck they will be perpendicular to the fretboard plane. The channel's width is 6 mm. It cuts right through the neck, so the depth is about 17 mm. A 250 mm long piece of ironwood with 6 x 17 mm cross section can easily hold my weight.
Marshall Dixon wrote:
...How about using aluminum? - it's cheap and readily available.
I wouldn't put aluminium in a vintage instrument. It has beautiful old rosewood back & sides and a nice old spruce top. I'm sorry about the fingerboard: it is made of very good quality ebony, but the fretwork is lousy and the overall thickness is bad, so I must make a complete new fretboard from scratch.
Paul Micheletti wrote:That should work......I had a piece of Spanish Cedar that I could easily flex with my hands. The hardwood inlay stabilized the neck nicely.

I've also used carbon fiber reinforcement beams in the past, but I prefer hardwood...
This neck is Spanish cedar, too. I also prefer hardwood. It suits much better to an old guitar. The ironwood piece will show from the backside of the neck beautifully.

Attila

Thanks for your comments.
Music to hear, why hear'st thou music sadly?
Sweets with sweets war not, joy delights in joy...

William Shakespeare, Sonnet 8

Marshall Dixon
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Re: Solving a neck problem

Post by Marshall Dixon » Wed Mar 15, 2017 3:44 pm

attila57 wrote:
Marshall Dixon wrote:
...How about using aluminum? - it's cheap and readily available.
I wouldn't put aluminium in a vintage instrument. It has beautiful old rosewood back & sides and a nice old spruce top. I'm sorry about the fingerboard: it is made of very good quality ebony, but the fretwork is lousy and the overall thickness is bad, so I must make a complete new fretboard from scratch.

Thanks for your comments.
[/quote]

I didn't realize the vintage aspect of this repair. Was more wondering about the use of aluminum in general. The only time I've read of it's use was by luthiers Boaz Elkayam and George Majkowski in an article in American Lutherie some years ago. Seems like a viable alternative to CF.

printer2
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Re: Solving a neck problem

Post by printer2 » Wed Mar 15, 2017 10:22 pm

I have used aluminum. Probably will make a spruce neck this weekend with it.
Fred

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attila57
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Re: Solving a neck problem

Post by attila57 » Thu Mar 16, 2017 9:40 pm

printer2 wrote:I have used aluminum. Probably will make a spruce neck this weekend with it.
Hmmm... Good idea! Although spruce is a bit too soft to resist the wear from the thumb. Are you going to put veneer on it? Veneering a spruce neck is common practice in lute building. Aluminum reinforcing would help Baroque lutes' necks stay straight!

Attila
Music to hear, why hear'st thou music sadly?
Sweets with sweets war not, joy delights in joy...

William Shakespeare, Sonnet 8

printer2
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Re: Solving a neck problem

Post by printer2 » Thu Mar 16, 2017 10:37 pm

attila57 wrote:
printer2 wrote:I have used aluminum. Probably will make a spruce neck this weekend with it.
Hmmm... Good idea! Although spruce is a bit too soft to resist the wear from the thumb. Are you going to put veneer on it? Veneering a spruce neck is common practice in lute building. Aluminum reinforcing would help Baroque lutes' necks stay straight!

Attila
I haven't found any problem with thumbprints on the back of the neck. I have a few dings from when it falls and hits a solid surface but that is to be expected. Made a few Fir necks that seem to survive also. I looked up the Janka hardness of Sitka (510) and compared it to Spanish Cedar (600 lbs). Not all that much softer but closer than with Poplar (540 lbs) which had been used for many department store catalog guitars. Just made a Telecaster neck out of Poplar for a body made out of a 2"x8" stud (this one with a real truss rod). I only use the softwood necks for fun lightweight builds that are not pretending to be anything else. The Spruce neck I want to do is for a Pine bodied Martin size 5 guitar. Just showing how to make an inexpensive guitar without too many tools.
Fred

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attila57
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Re: Solving a neck problem

Post by attila57 » Fri Mar 17, 2017 6:22 pm

printer2 wrote:
....Poplar (540 lbs) which had been used for many department store catalog guitars. Just made a Telecaster neck out of Poplar for a body made out of a 2"x8" stud (this one with a real truss rod). I only use the softwood necks for fun lightweight builds that are not pretending to be anything else. The Spruce neck I want to do is for a Pine bodied Martin size 5 guitar. Just showing how to make an inexpensive guitar without too many tools.
I didn't know that Poplar is used to make guitar necks...
Music to hear, why hear'st thou music sadly?
Sweets with sweets war not, joy delights in joy...

William Shakespeare, Sonnet 8

printer2
Posts: 284
Joined: Sat May 02, 2015 9:20 pm
Location: Winnipeg

Re: Solving a neck problem

Post by printer2 » Fri Mar 17, 2017 10:39 pm

attila57 wrote:
printer2 wrote:
....Poplar (540 lbs) which had been used for many department store catalog guitars. Just made a Telecaster neck out of Poplar for a body made out of a 2"x8" stud (this one with a real truss rod). I only use the softwood necks for fun lightweight builds that are not pretending to be anything else. The Spruce neck I want to do is for a Pine bodied Martin size 5 guitar. Just showing how to make an inexpensive guitar without too many tools.
I didn't know that Poplar is used to make guitar necks...
Not that popular now days :lol:

but in the past, Kay, Stella, Harmony, Silvertone, Regal, Danelectro.
Fred

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