Lee: Thanks for the clarification on iron density. I got my info from *Know Your Woods* by Albert Constantine, Jr. Revised by Harry J. Hobbs and published by Charles Scribner's Sons. The hardness test link is a great resource for flooring products.
Tim On Sat, Oct 31, 2009 at 5:01 PM, Lee Frelich <[email protected]> wrote: > > ENTS: > > The Janka hardness test for wood is an interesting measure--it is the > amount of force required to embed a 0.444 inch diameter steel ball in > wood to half its diameter. It was developed to rate woods for resistance > to denting when used for flooring. See its description and a list of > wood hardness at this website: > http://en.wikipedia.org/wiki/Janka_hardness_test > > Lignum vitae comes out at the top of the list at 4500 pounds-force, > compared to 1700 for black locust and 1450 for sugar maple. There are > many tropical woods in the 2000-3700 pounds-force range. > > Regarding density, actually no wood approaches iron, which has a > specific gravity of 7.87, so that a cubic foot of it weighs 491 pounds > at room temperature, compared to 81.1 pounds for Lignum vitae. Balsa > wood has a specific gravity of 0.2, so a cubic foot of it weighs 12.5 > pounds, although keep in mind that all these statistics are the average > of several tests, and that there is variability within each species. The > matter in a typical neutron star is much denser than any known wood, > with a specific gravity of 370-590 trillion, so that a cubic foot would > weigh 190-300 trillion tons. > > Lee > > > Timothy Zelazo wrote: > > Guaiacum officinale, Lignum vitae is the hardest, heaviest and > > closest-grained wood known and has a density almost equal to iron. > > The weight is about 83 lbs. per cubic foot with a specific gravity of > > 1.3. It also has the ability to withstand the great working pressue > > of 2,000 lbs. per square inch and has resistance to the action of many > > mild chemicals and acids. One application is for propeller-shaft > > bearings in the largest liners. > > > > There are about eight distinct botanical species which are listed and > > referred to as ironwoods. A few are Billian, Hophornbeam Eastern, > > Ipil, Mesua, Pau d'Arco, Pau Ferro, Pyinkado, Quebracho, and Hornbeam > > European. The common name "ironwood" is generally applied to whatever > > wood in any particular section of the country is considered the > > densest and the hardest. > > > > On Sat, Oct 31, 2009 at 2:56 PM, Timothy Zelazo <[email protected] > > <mailto:[email protected]>> wrote: > > > > Cornus florida has a cubic weight per foot of 50 lbs. also used > > for golf-club heads. > > > > Xylia xylocarpa, Pyinkado known as the iron wood of Burma weighs > > 70 to 81 lbs. per cubic foot. > > > > Andira inermis, Partridge wood is about 75 lbs. per cubic foot > > which emanates from Venezuela and Colombia. > > > > Prosopis glandulosa, Mesquite averages 55 lbs. per cu. ft. and > > found in Arizona, Texas, and Oklahoma. > > > > Carpinus betulus, European Hornbeam is considered one of the > > hardest woods growing in England. > > > > Ostyra virginiana, Eastern Hophornbeam is about 51 lbs per cu ft. > > > > Russ, thanks for the walking stick info. I've experienced the > > same results when working the species you mentioned. > > > > Tim > > > > > > > > On Sat, Oct 31, 2009 at 2:21 PM, <[email protected] > > <mailto:[email protected]>> wrote: > > > > ENTS: > > > > Of all the smaller eastern trees I would give dogwood, Cornus > > florida a vote for one of the hardest woods. Over the years I > > have used all sorts of woods for walking sticks and I have > > found that dogwood does not split or splinter like hickory and > > it doesn't shred or warp like hophornbeam. Hornbeam, Carpinus > > caroliniana, seems to be fairly soft, it is easy to cut with a > > knife it splits extremely easily and it will rot while you are > > looking at it. > > > > Ostrya viginiana, hophornbeam splits extremely easily and > > warps very badly. > > > > Walking sticks made out of dogwood never split on the point > > end and with daily use will wear at a rate of less than half > > an inch a year. Nothing else compares in terms of wear and no > > tree I have tried for a walking stick has been more stable > > than dogwood is once it has seasoned. > > > > Oak and ash walking sticks break much easier than dogwood and > > are much heavier > > > > If you make a walking stick out of dogwood it is best to dig > > out the entire tree and trim the roots with loppers. The best > > size tree is, usually about 1" in diameter and has a straight > > stem for at least four feet above the root collar. Carve the > > handle out of the root ball. You can almost always get a very > > comfortable hook to it. In my walks around the steep hills of > > WV a dogwood walking stick has become my third leg....the one > > that never slips. > > > > When freshly, cut a dogwood tree can be carved into a walking > > stick with just a jack knife but once it dries it is like > > trying to carve bone. > > > > When completely dried the wood is very light, which would mean > > it is weak if one of the measures of strength is density. > > > > The walking stick in the photo is over five years old. The > > patina that develops from long term use makes it very > > comfortable to hold and after several years of use it becomes > > a fairly reliable tool.....that hook on the end is extremely > > helpful to pull the tip of a 10' high limb down close enough > > to tie plastic ribbon when you are marking a trail in dense > > brush. > > > > Other woods may be slightly harder in certain uses but nothing > > I've encountered compares to the utility of a dogwood tree. > > > > > > Russ > > > > > > -----Original Message----- > > From: Timothy Zelazo <[email protected] > > <mailto:[email protected]>> > > To: [email protected] <mailto: > [email protected]> > > Sent: Sat, Oct 31, 2009 1:52 pm > > Subject: [ENTS] Re: What's the hardest hardwood? > > > > Carpinus caroliniana is American hornbeam (bluebeech, water > > beech) and Ostrya virginiana is Eastern hophornbeam and had > > the common name "ironwood" often applied to this species. The > > Textbook of Dendrology by Harlow and Harrar Fifth Edition > > published by McGraw-Hill. This was the info they were pushing > > over thirty years ago when I studied forestry. The two trees > > look very different in the forest. > > > > On Sat, Oct 31, 2009 at 1:36 PM, Josh Kelly > > <[email protected] > > <mailto:[email protected]>> wrote: > > > > > > Don, > > > > On the contrary, I think I noted hop hornbeam (Ostrya > > virgiana) in my > > earlier post. > > > > Josh > > > > On Oct 31, 1:11 pm, DON BERTOLETTE <[email protected] > > <mailto:[email protected]>> wrote: > > > Josh- > > > > > > I guess that 'ironwood' (aka eastern hophornmeam, > > American hornbeam, Ostrya virginiana; member of the > > Betulaceae), member of the doesn't rate in this exotic > group? > > > > > > -Don > > > > > . Learn > > more.http://www.microsoft.com/windows/pc-scout/default.aspx? > > CBID=wl&ocid=P. > > < > http://www.microsoft.com/windows/pc-scout/default.aspx?%0ACBID=wl&ocid=P > .>.. > > > > > > > > > > > > > > > > > > > > > > > > > --~--~---------~--~----~------------~-------~--~----~ Eastern Native Tree Society http://www.nativetreesociety.org Send email to [email protected] Visit this group at http://groups.google.com/group/entstrees?hl=en To unsubscribe send email to [email protected] -~----------~----~----~----~------~----~------~--~---
