Lignum Vitae, Latin for "Tree of Life," is the national tree of the Bahamas. It's also the world's densest wood, and has such unusual properties that the USS Nautilus, the world's first nuclear-powered submarine, has its aft main shaft strut bearings made out of the stuff. In addition to being strong, hard, heavy, dense, water- and salt-water-resistant, Lignum Vitae contains natural oils that make the bearings self-lubricating.
The USS Nautilus isn't an anomaly; Lignum Vitae has been used as propellor shaft bearings in conventional ships, and hydroelectric plants dating back to the 1920s have used bearings for their turbines made out of the stuff.
Virginia-based Lignum Vitae Bearings calls their product "the world's only renewable (and greenest) bearing on the market." Company President Bob Shortridge has acquired land in the Bahamas, one of the tree's native origin islands, and plants at least one Lignum Vitae tree for every block of the stuff that passes through his facility. "Although Lignum Vitae has been harvested for over 500 years before I was born," Shortridge writes, "I feel an obligation to replace it... I wish for this incredibly useful wood to be available for generations to come."
Here's Shortridge himself explaining Lignum Vitae's properties and applications:
This factoid came to us by way of Rob Wilkey, Core77's newest guest writer, who will shortly be breaking down the properties of different species of wood. Stay tuned for his contributions to our Material Matters: Wood series.
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It's good for tools too.
It is! LV woodcarving mallets have been popular for a long time, since you only need a small volume of wood to get the right heft for a mallet. And they're durable to boot!
And I have to point out one small thing - the planes in your link seem to be made from Verawood, not Lignum Vitae. Very similar woods in many ways, but there are some visual markers that separate them, primarily that bright green color: http://www.hobbithouseinc.com/personal/woodpics/_discussion_lignum_vs_verawood.htm
I think it passing disgusting how environmentalists first deny the existence of God then in their arrogant turn right around and try to play God as in "we are here to save the planet".....they can't even keep alive their own souls and yet they would have everyone believe they can create humans and know all about managing a planet as if they built it and they own it....thas the perfect example of a religious nut job who belongs in a loony bin.....the very ones screaming the loudest to save the planet are actually the ones most dangerous to the human race ...public enemies
Lignum Vitae is Waterproof, Yes. To Ray Doeksen: Wood working is not altruism you nihilst!!!!!!
Jon, I think you may be assuming density and hardness are the same. From what I found, Lignum Vitae is actually more dense than Australian Buloke, even though it has a lower Janka hardness. If you look on wood-database.com, it lists the density of Lignum Vitae at 1,260 kg/m^3, while Australian Buloke is listed at only 1,110 kg/m^3.
didn't know that.
I used to work for a company where had some maintenance projects for hydroelectric plants (some of them dating form 1910-1920's but remodeled in 50's-60's) and never found those Lignum Vitae bearings. Instead of them I found Brass+Pb which I think they have more or less the same worklife.
Mostly the only maintenance operation was to dissasemble them for cleaning, sanding a little to get a uniform surface without scratchs and measuring to confirm that tolerances where ok. But the whole dissamsembling porcess takes almost 10 days and they only were 1 MW turbines.
My question was more if wood would need more or less inspections or maintenance operations than other materials.
Anyway it seems like an awesome material.
As far as I know, Lignum Vitae is a better choice than synthetic in any situation where the bearing is exposed to water, but not to sand or sediment. It is not as dense as steel or synthetics, so it won't endure exposure to sand or other dense debris. However, in applications such as hydroelectric dams, it is the ideal candidate as it is commonly less expensive, is self-lubricating, and lasts almost indefinitely even under pressurized water exposure.
The reason that it saw a drop in use many decades ago was due to a steep decline in the population of the Guaiacum genus of trees that it is harvested from. Due to modern environmental restrictions and responsible harvesting, Lignum Vitae is available at reasonable prices again. I applaud Mr. Shortridge's efforts to sustain the species for future generations.
The only "responsible" part is the owner of the company planting new trees which is self serving anyway as it is part of what makes him money.
Still and incredible use of wood.
I wouldn't call it self-serving when the trees a person plants won't be available for useful harvest within their lifetime. Enlightened self-interest, barely. Very close to true altruism.
Because I don't really see the point of trying to go green in a so important component of a turbine.
I mean, being a hydro-power plant already green energy, you become more green increasing the production of renewable energy not reducing it because of more maintenance operations.