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Hluth
11-28-2015, 04:12 AM
About 8 years ago I acquired a quantity of Philippine narra hardwood. Much of it was quarter sawn and I liked the way it looked, so I started using it for backs and sides and eventually necks. But the test of time has caused me to stop using it altogether. It turns out that its structural integrity seems to be low, and under string load, it might deform. The last straw was a narra body that actually deformed at the waist (see picture below). I also had 3 bowed necks come back to me after being under load for a few months. The stuff is lighter than mahogany and very porous, and that might be the reason for the problem The other two pictures are of a .065 thick piece of narra showing thin CA glue spread on one side and where it ran through the pores on the other. I have built narra instruments that have held up fine and sound good, but a few bad ones are a few too many.

85871 85872 85873

Allen
11-28-2015, 09:38 AM
The problem with using "Narra" stems from it being a common name for any number of species that look similar. All being a species of Pterocarpus.

In Australia don't use the name Narra that I'm aware of. We have what is commonly called New Guinea Rosewood (Pterocarpus indices). It ranges from a pale straw color, through to deep red. And figure from straight, through rope, rain drop, curly and bees wing.

New Guinea Rosewood makes fantastic instruments. Very stable and great tone. It has a very distinct smell when working it and can be a bit over powering at times. The pores can be huge, so if you want a high gloss finish, you have your work cut out for you in filling them.

Also many people develop allergies to it.

billten
11-28-2015, 10:34 AM
Agreed with Allan, narra is a generic name for a type of local hardwood tree in the philippines and it varies enormously from white to red and soft to hard as a rock. I am quite sure that the wood referred to as Philippine narra could have actually come from several different species. I make furniture at my house in Cebu, Philippines from narra and other local woods and i always buy the darkest and heaviest narra i can find but even then it's a roll of the dice on how it turns out. I prefer many of the other local hardwoods for this reason.

Beau Hannam Ukuleles
11-29-2015, 12:56 PM
You are simply wrong Hluth, or perhaps you bought some other wood???. I explain why below.

I have used New Guinea rosewood necks on most of the 455 instruments (35 guitars a year over 13 years while i was there) we made at Gilet guitars in Sydney Australia since 2003 (not to mention the- ill say 100- student guitars we helped build).
We never had any neck issues and we used it for 12 string guitars, which have about 250 Lb of string tension (with light strings- see below for link) to a tenor ukes 40ish Lbs!!!
So, i think you have something other then what we are working with as neck deformation is just not possible for a uke when using Pterocarpus indices, aka, Narra & New Guinea Rosewood. (it should smell like roses when you cut it.)

Check out these stats which show Narra outperforming in all fields except weight but a previous post of mine shows the weight difference is actually very little (30 grams or so) with a uke neck.
Narra- aka New Guinea Rosewood
Common Name(s): Narra, Amboyna (burl)
Scientific Name: Pterocarpus indicus
Average Dried Weight: 41 lbs/ft3 (655 kg/m3)
Specific Gravity (Basic, 12% MC): .54, .66
Janka Hardness: 1,260 lbf (5,620 N)
Modulus of Rupture: 13,970 lbf/in2 (96.3 MPa)
Elastic Modulus: 1,724,000 lbf/in2 (11.89 GPa)
Crushing Strength: 8,270 lbf/in2 (57.0 MPa)
Shrinkage: Radial: 2.8%, Tangential: 4.0%, Volumetric: 6.9%, T/R Ratio: 1.4
http://www.wood-database.com/lumber-identification/hardwoods/narra/
85938

Honduran Mahogany
Scientific Name: Swietenia macrophylla
Average Dried Weight: 37 lbs/ft3 (590 kg/m3)
Specific Gravity (Basic, 12% MC): .52, .59
Janka Hardness: 900 lbf (4,020 N)
Modulus of Rupture: 11,710 lbf/in2 (80.8 MPa)
Elastic Modulus: 1,458,000 lbf/in2 (10.06 GPa)
Crushing Strength: 6,760 lbf/in2 (46.6 MPa)
Shrinkage: Radial: 2.9%, Tangential: 4.3%, Volumetric: 7.5%, T/R Ratio: 1.5
http://www.wood-database.com/lumber-identification/hardwoods/honduran-mahogany/
85939

Spanish Cedar
Scientific Name: Cedrela odorata
Average Dried Weight: 29 lbs/ft3 (470 kg/m3)
Specific Gravity (Basic, 12% MC): .38, .47
Janka Hardness: 600 lbf (2,670 N)
Modulus of Rupture: 10,260 lbf/in2 (70.8 MPa)
Elastic Modulus: 1,323,000 lbf/in2 (9.12 GPa)
Crushing Strength: 5,860 lbf/in2 (40.4 MPa)
Shrinkage: Radial: 4.1%, Tangential: 6.2%, Volumetric: 10.2%, T/R Ratio: 1.5
85940


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jcalkin
11-29-2015, 01:52 PM
I made a hammered dulcimer frame out of red narra from a hardwood lumber yard in N.J. It was very pretty, heavy and hard, but I didn't even get it tuned up before it began to give way. That's not a lot of evidence, but I never tried it again.

Beau Hannam Ukuleles
11-29-2015, 05:04 PM
My experience is using it as a neck wood so that is all I will stake my name on.

Interesting- perhaps it isn't a good back/sides wood? I don't know.

Allen
11-29-2015, 09:15 PM
I certainly wouldn't call any of the New Guinea Rosewood that I've worked with as heavy and hard. Sure it's not spruce, but it sure isn't ebony or Gidge either.

Hluth
11-30-2015, 09:18 AM
Okay, here’s the story. I bought the wood locally from a person I know whose father-in-law salvaged it in the Philippines around 1946 (he was stationed there during WW2 and stayed for a few years after the war was over). I also bought a large quantity of komogong ebony that came from the same source. Both woods are native to the Philippines. After reading billten’s post which suggests that narra varies from dense to soft, I’m thinking that the wood I got is softer than most. It’s also possible this is a different species, but it looks like other narra samples I’ve seen, and it has a sweet rose-like aroma. The good news is that I can’t say enough about the ebony—it’s the best and most valuable wood I have!

warndt
12-01-2015, 10:03 AM
Jerry,
I own one of your 2008-2009 5-string M-Style tenors, with mahogany top and narra b/s.

This one seems to be holding up just fine, and sounds just as nice as some of your other, more traditional wood combinations.

William