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http://www.sizes.com/units/janka.htm

struck me as pecular but according to this janka scale it is ????

Verrrry interestink!

One wonders how many samples they tested.

Wow...dazzle 'em with bulls..t, eh?

What a crock...

Heh, this is a strange co-incidence. It was only a couple of days ago I first ran across janka hardness ratings on a page dedicated to charting which common cabinetmaking wood offcuts make the best firewood (seriously) (oh, and I wasn't actively looking for firewood information it was one of those sites you 'stumble across')

What immediately strikes me are that this is side hardness as opposed to end hardness, the two can be very different and on the other site there were lots of examples where a type of wood with greater side hardness than another type had less end hardness and vice versa.

Also, note that these are measures at a rather unhelpful '12% moisture content'. Why unhelpful, well - again, on that site (being about firewood) it described how there are several different ways of expressing moisture content of wood using percentages. They vary from weight of green versus 'dry' wood through to proportion of remaining wood which is wood fibres versus water. Without knowing which test is applied it would impossible to compare as to whether this data is accurate as to 'dried' wood used in luthierie etc

Actually BRW sure does crack more readily than IRW doesn't it? So perhaps it's not that innacurate.

Of course, science can only take us so far - I suppose the final acid test is the ole 'caveman test' - so which of you guys/gals with stock of IRW and BRW fancies smacking a few planks of each against each other to see which one breaks first?...

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^^Above post posted by the artist formerly known as Dave Bamber^^

IRW is 1760 Janka hardness, not more:
http://www.efloors.com/qwikfacts/Janka.asp

I can only tell you that Brazilian rosewood burns with wonderful colors dancing above the surface with the volatile oils off-gassing, evaporating, and combusting. I'd think that compressed briquettes of BZ would be wonderful in pellet stoves...ebony not so good...and German or Adi spruce is only good as fire-starter, while western red cedar has some nice oils to add to the mix...

Questioning the sample ratio is a very wise thing to do.

I have handled a LOT of Jarrah in my time. Some is as light as mahogany both in colour and in m3, some is just about as heavy as ebony and near as dark. This phenomenon has everything to do with growth conditions IMO.

It has been my experience that if you have a tree which has been grown with abundant sunlight and nutrients, has received adequate rain fall, and established itself in a soil PH which makes all of the above exploitable, the converted timber from that tree will be much less dense than that which is converted from a tree of the same size and species that has been grown in a more testing extreme of that species ecological tolerable environment.

Take each board as it comes is my thought, if you think you know all there is to know about a certain timber, you probably have not worked enough of it to teach you not to ever make assumptions.

Cheers

Kim

Interesting...if I were to use this chart to select a bridge plate material, Maple would not even make the short list. Yet it's one of the most common choices. Just another case of junk science IMO.

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JJ
Napa, CA
http://www.DonohueGuitars.com

if your talking bolivian rosewood .. I think thats a different continent than indian rose wood .. but hey .. l am no expert jody

and IPE is harder yet

I will have to see how well it burns.

Todd , thanks for the excellent link ... Jody

They have maple about right on that chart. What differs from your preconception should not be assumed to be junk science.

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.