A comparison between Blackwood and Cocuswood

[Sillydill]

Hey Lorenzo,

Sorry I couldn’t find any Janka values for Cocus (Jamaican Ebony, Brya ebenus). But I did find values for Blackwood (Mpingo, Dalbergia melanoxylon), ranging from 1750# (this could be for one of the Acacia species) to 4050#.

I don’t believe the Janka values are the best for our purposes anyway. The Janka value is the pounds of force necessary to drive a 0.444-inch diameter steel ball halfway into a wooden board (depth of 0.222-inches). This includes a fair amount of crushing the wood fibers.

I think something like scratch resistance would be more appropriate (wanting to measure the force necessary to disrupt the surface tension of the material). I can state that the Cocus flutes I’ve had were more resistant to scratching than my Blackwood flutes. But admittedly, most of my Cocus flutes have been seasoned antiques (about 150 years old).

Cocus seems to form high surface tensions as it ages, this contributes to its surface hardness. But these tensions are also why old Cocus is so brittle.


I have a set of turning squares of Lignum Vita (Janka = 4500#) that someday I would like converted into a flute. But I would also like to have a flute made of Balsa (Janka = 88#) for comparison. Then I would like to apply a bore coating of graphite epoxy to the Balsa flute, to see how the tone and performance would be affected.

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Bottom Line = I wouldn’t go out of my way to obtain a flute made of Cocus over one made of Blackwood.

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Here is an excerpted list of the 125 hardest woods on earth (by Johnny W. Morlan) :

The Hardest Wood In The World Or On Earth Is
1 - Baraúna - Quebracho - Soto {Schinopsis brasiliensis/glabra} 4800
4800 Pounds Force {lbf} - 2177 Kilograms Force {kgf} - 21.35 Kilonewtons {kN} - 21350 Newtons {N}
2 - Belah {Casuarina cristata} 4500
2 - Lignum Vitae - Tree Of Life {Guaiacum officinale} 4500
2 - Waddy Wood {Acacia peuce} 4500
3 - Mgurure {Combretum schumanii} 4430
4 - Lignum Vitae - Holywood {Guaiacum sanctum} 4400 - Hardest Wood In United States
4 - Red Bauhinia {Lysiphyllum carronii} 4400
5 - Curupay - Kurupay {Anadenanthera colubrina} 4390
6 - Tubi - Blackwood Solomon - Ebony Queen {Xanthostemon melanoxylon} 4370
7 - Knob Thorn {Acacia nigrescens} 4290
8 - Gidgee {Acacia cambagei} 4270
9 - Tiga {Tristania decorticata} 4260
10 - Snakewood Australian {Acacia xiphophylla} 4150
10 - Wattle Lakewood {Acacia enervia} 4150
Brown Spearwood {Acacia rhodoxylon} 4100
Gimlet {Eucalyptus salubris} 4090
Blackwood African {Dalbergia melanoxylon} 4050
Wattle Australian Ironwood {Acacia excelsa} 4050
Jutahy {Dialium guianense} 4000
Lignum Vitae Argentine {Bulnesia sarmientoi} 4000 Note: Not related to #1 or #3 Lignum Vitae
Verawood {Bulnesia arborea} 4000 Note: Related to but different from above
Blackbutt Dundas {Eucalyptus dundasii} 3960
Miraúba {Mouriri callocarpa} 3960
Ebony Brown {Libidibia paraguariensis} 3900
Curupay - Mahogany Andean {Piptadenia macrocarpa} 3840
Morrel Red {Eucalyptus longicornis} 3840
Coolibah {Eucalyptus microtheca} 3820
Ebony Red {Erythrophleum chlorostachys} 3820
Mulga {Acacia aneura} 3820
Snakewood {Piratinera guianensis} 3800
20 - Urucurana {Sloanea nitida} 3720
Olivewood Brazilian {Ferreirea spectabilis} 3700
Ebony Brazilian {Swartzia tomentosa} 3690
Ipe {Tabebula serratifolia} 3680
Maria Preta {Zizyphus itacaiunensis} 3680
Leadwood {Krugiodendron ferreum} 3660
Momoqui {Caesalpinia pluviosa} 3660
Sapote {Licania sparsipilis} 3570
Wawra {Combretum imberbe} 3570
Orosi {Dipteryx panamensis} 3540
Shihuahuaco {Dipteryx micranta} 3540
Teak Brazilian {Dipteryx odorata} 3540
Katalox {Swartzia cubensis} 3510
Jarána {Holopyxidium jarana} 3500
Redwood - Boongul {Eucalyptus transcontinetalis} 3500
Desert Oak Australian {Acacia coriacea} 3480
Gum Salmon {Eucalyptus salmonophloia} 3480
30 - Uxirana {Vantanea parviflora} 3470
Cachaporra Do Gentio {Terminalia argentea} 3460
Macucu Branco {Licania oblongifolia} 3460
Morrel Black {Eucalyptus melanoxylon} 3460
Umzimbeet {Millettia grandis} 3450
Cabreúva Parda {Myrocarpus frondosus} 3440
Box Bimble {Eucalyptus populnea} 3390
Box Grey {Eucalyptus microcarpa} 3370
Box Red {Eucalyptus intertexta} 3370
Mallet Brown {Eucalyptus astringens} 3370
Wandoo {Eucalyptus wandoo} 3370
Angelim Rajado {Marmaroxylon racemosum} 3350
Azobe {Lophira alata} 3350
Blackwood Burmese {Dalbergia cultrata} 3350
Rosewood Kingwood {Dalbergia cearensis} 3340
Caraiperana {Licania gracilipes} 3330
Casca Preciosa {Aniba canelilla} 3310
40 - Buddah {Eremophila mitchellii} 3280
40 - Pau Santo {Zollernia paraensis} 3280
Muirapixuna {Cassia scleroxylon} 3270
Abiu Pitomba {Pouteria egregia} 3260
Ebony Macassar {Diospyrus celebica} 3250
Angelim Vermelho {Dinizia excelsa} 3220
Boxwood Hickory Australian {Planchonella euphlebia} 3220
Ebony Ceylon {Diospyros ebenum} 3220
Muirapiranga {Brosimum acutifolium} 3220
Rosadinho {Pouteria anomala} 3220
Casuarina {Casuarina equisetifolia} 3200
Mahogany Mountain {Cercocarpus ledifolius} 3200
Beefwood {Manilkara bidentata} 3190
Rata Southern {Metrosideros lucida} 3180
Rosewood East Indian {Dalbergia latifolia} 3170
Cuchi {Astronium urundeuva} 3150
Gum Grey {Eucalyptus propinqua} 3150
Ironbark Grey {Eucalyptus paniculata} 3150
Ironbark Red Broadleaved {Eucalyptus fibrosa} 3150
Ironbark Red Narrowleaved {Eucalyptus crebra} 3150
Myall Weeping {Acacia pendula} 3150
Rata Northern {Metrosideros robusta} 3150
Sheoak Rose {Casuarina torulosa} 3150
50 - Leopard Tree {Caesalpinia ferrea} 3140
Anoerá Ferro {Acioa lehmbachii} 3120
Cuerno De Ternero {Bucida macrostachya} 3120
South African Black Ironwood {Olea laurifolia} 3120
Sapucaia {Lecythis pisonis} 3100
Sonoran Desert Ironwood {Olneya tesota} 3080
Barrote {Tetragastris panamensis} 3050
Angelim Pedra {Hymenolobium petraeum} 3040
Betharaba {Tabebuia avellanedae} 3040
Belian {Eusideroxylon zwageri} 3020
Abiurana {Couepia robusta} 3000
Angico {Parapiptadenia rigida} 3000
Chin Chan {Dalbergia oliveri} 3000
Rosewood Madagascar - Rosewood French {Dalbergia greveana} 3000
Tamarind {Tamarindus indica} 3000
Teak Rhodesian {Baikiaea plurijuga} 2990
Cuiarana {Buchenavia grandis} 2980
Muhimbi {Cynometra alexandri} 2970
60 - Tuturubá {Pouteria oblanceolata} 2970
Aromata {Clathrotropis brachypetala} 2960
Rosewood Cocobolo {Dalbergia retusa} 2960
Uxi {Endopleura uchi} 2950
Banga Wanga {Amblygonocarpus andongensis} 2940
Cape Plane {Ochna arborea} 2940
Mopane {Colophospermum mopane} 2940
Nieshout {Ptaeroxylon obliquum} 2940
Pracuúba Da Terra Firme {Trichilia lecointei} 2940
Tambootie {Spirostachys africana} 2940
Missanda {Erythrophleum ivorense} 2930
Bloodwood Brown {Eucalyptus trachypholia} 2920
Box Grey Coast {Eucalyptus bosistoana} 2920
Box Yellow {Eucalyptus melliodora} 2920
Ironbark Red {Eucalyptus sideroxylon} 2920
Leopardwood Australian {Flindersia maculosa} 2920
Sasswood Tree {Erythrophleum suaveolens} 2920
66 - Bloodwood {Brosimum rubescens} 2900
66 - Kaneelhart {Licaria canella} 2900
66 - Pau Branco {Drypetes variabilis} 2900

[LorenzoFlute]

Seems like cocus wood is not in the top 125 hardest woods. Mopane (similar to cocus, some people say) it's almost at the end. I wonder if hardness does matter, or if it's mostly about density...

[Sillydill]

Hey Lorenzo,

Cocus doesn't make the list because it is commercially extinct!

Only Irish Flute and Bag-Pipe makers seem to seek it.

[Sigurthr]

I would love to see a list like that but of Density.

[Sillydill]

Hey Sigurthr,

Try here: http://www.csudh.edu/oliver/chemdata/woods.htm

Or here: http://tropix.cirad.fr/index_gb.htm

[Aanvil]

Oh Cocuswood! Thou art my Density!

[Denny]

don't be twistin' JD's nickers....

[Tommyflute]

Thank you lads, for fantastic answers, but also for new questions and ideas: It would be great to hear the opinion of flutemakers, too (yes, I know they're between us... )

At this point we can conclude that cocuswood and blackwood sound quite the same, but even if it can only be an idea, whit no scientifical bases, lots of players say that they feel in a different way while playng a cocuswood rather than a blackwood flute.

In particular I have a question for you: Is blackwood louder, while cocuswood more round, flexible and mellow?
I ask this 'cause it probably is the opinion of the majority of flute players I've thalked to (I said the majority, not all...).
But now the show must go on...

PS - for Othannen - Lorenzo, I think we don't need a moderator, so could you express your opinion once and for all?

[Terry McGee]

Fascinating list, Sillydill, thanks! I'm intrigued that most of those hardest timbers appear to be Australian (most acacias and eucalypts are from here).

From your list, I've used:
2 - Lignum Vitae - Tree Of Life {Guaiacum officinale} 4500
6 - Tubi - Blackwood Solomon - Ebony Queen {Xanthostemon melanoxylon} 4370
8 - Gidgee {Acacia cambagei} 4270
Blackwood African {Dalbergia melanoxylon} 4050
Wattle Australian Ironwood {Acacia excelsa} 4050
Ebony Red {Erythrophleum chlorostachys} 3820
Mulga {Acacia aneura} 3820
Box Red {Eucalyptus intertexta} 3370
Rosewood Cocobolo {Dalbergia retusa} 2960
plus a few other acacias not on the list (and possibly not hard enough to be on it), and cocuswood.

My feeling is that they are pretty much the same until you get down to Mulga, where I feel the sound and response is more approaching boxwood. Their densities are also more approaching boxwood, so whether it's a matter of hardness or density, I don't know.

On the topic of surface hardness, I suspect most timbers form a "skin". Certainly, when you go back to re-ream a flute in production, after some period, I get the feeling that the reamer has to "break through" before it can cut freely again. Could be imaginitis, of course!

My own guess is that it has more to do with surface porosity than denseness or hardness, although these are probably indicative of fineness of grain.

The other datapoint we need to look at is Delrin, which has a density of around 1.4 (compared to blackwood at 1.2 and boxwood at 1.0) but I imagine not a high hardness? But it certainly makes a very responsive flute.

Terry

[LorenzoFlute]

PS - for Othannen - Lorenzo, I think we don't need a moderator, so could you express your opinion once and for all?

A moderator? Anyway, I didn't express my opinion because I didn't try a cocus wood flute for long enough to judge it. And you wanted only direct experiences, didn't you? But i'm also interested in this topic, that's why I wrote.

Terry, you also use Mopane {Colophospermum mopane} 2940, right?

[pflipp]

Ah. I think I finally nailed the definitive answer to this one.

Whether or not different timbers produce different timbres may depend on whethre it's American or British English.

Whether or no whetre.

[uillmann]

what kind of Blackwood we are talking about?
and what kind of Cocus we are talking about?

These would likely be the most relevant questions in my mind. There is a big difference between old growth, nearly black, slow growing, and glassy smooth cocus and the current commercially available cocus that grew rapidly and has wide annular rings and may be predominately light tan, and full of microscopic voids. Blackwood, too, can be dense black and smooth-surfaced, or it can be a drab brown and comparatively rather rough-grained. The bore finish will depend on the actual pieces of timer in question, and I would hazard to say that it is this microfinish which would have some of the most dramatic effects on the sound of a completed flute. Additionally, I would submit that some of the less dense examples might soak up a great deal of linseed oil, which would then harden (crystalize ? polymerize ?) inside the timber and change its properties somewhat. A good flute maker might, (should?) introduce the copious amounts of this oil and allow it to dry long before the bore is finished in order to obtain a superior result. Of course, that may all be baloney that I made up just now...

[Michel]

here's my humble opinion on it. Bear in mind that I do not have any technical or technological knowledge whatsoever.
I owned and played on daily basis a cocus flute for a good while (3/4 years) and tried some others both antique and modern. I had a chance to play two very similar flutes (same model by same maker, Tom Aebi) of which one was blackwood and the other cocus. I thought the blackwood one was more sonorous and darker while the cocus was somewhat brighter and more flexible.

[LorenzoFlute]

Wow, four italians on this thread

[Casey Burns]

I've turned enough Cocus and lots of blackwood that I can make a comparison.

Blackwood is much more stable. Almost every cocus wood flute I turned split, even though the wood measured at 8% in my workshop.It may have been that the log I used had inherent stresses. This was the primary reason why my experiment with it ended, once I used up the log.

Because of its rarity cocus is generally more expensive!

Once turned both woods move to some degree and I plan for this. The bore goes slightly oval which has a beneficial effect on the tone. Like boxwood, cocus does this right away. Blackwood takes about a year to catch up.

Its tone may be a little warmer than blackwood at first (richer in overtones). But blackwood catches up. Mopane is very close to cocus in tone right out of the gate. I still like Mopane the best.

There are several species of wood that would be suitable for flute making, as the list posted above suggests. There is one very hard and dense species here in the NW called Mountain Mahogany. But most flute makers including myself have little or no time and experience to go log these species. Thus we are subject to what we can get commercially. Also, what is likely to remain available, what is relatively affordable (Pink Ivory and Snakewood are lovely woods but frightfully expensive), safe to work with (cocus is definitely not, with its uriosol-like oils, and I am allergic to most rosewoods and ebonies), what is stable, and what is close enough to be dry and ready to use. Much of the cocus on the market still needs some years of curing and drying. I can get dry blackwood. The mopane needs a few years and boxwood can be microwaved. So there it is. These work for me well and I have little incentive to try other woods.

Casey