Thread: Black wattle, the hardest wood

Add pics of how you are trying to do it also if you can.

I know I am trying to hog out the inside of the bowl into end grain, that is the problem. I'll get some pics up soon.

Dry Wattle Black {Acacia mangium} is rated at 1750 lbs force hardness while Wattle Green {Acacia decurrens} is 2250 lbs.
Both are softer than Gum Spotted {Eucalyptus maculate} being around 2470 lb

The hardest reported wattle is Wattle Lakewood {Acacia enervia} and at 4150 lbs is the 12the hardest wood on earth.

Wattle Australian Ironwood {Acacia excelsa} is 4050 lbs and 16th hardest.

All other Wattles are less than those above.

REF: Wood Species Janka Hardness Scale/Chart By Common/Trade Name

Bob, you and Runge should join forces!!

At those sorts of hardnesses I guess 12th and 16 are relative. Generally they can be described as bloody hard.!!

interesting link bob thanks , but i had a good look on there and i cant find cooktown iron wood ........ Erythropleum Chlorostachys.
shame cos i have a little lump of it and would like to of know where it fell on the hardness scale .

Well here are the pics.

The problem is going into the end grain, cutting the long grain is fine.




It's starting to crack a bit.





This is the other half of the blank. I think I'll be cutting it up for pen blanks.

Originally Posted by texx

interesting link bob thanks , but i had a good look on there and i cant find cooktown iron wood ........ Erythropleum Chlorostachys.
shame cos i have a little lump of it and would like to of know where it fell on the hardness scale .

It's there - listed as Ebony Red {Erythrophleum chlorostachys} 3820 = so yeah pretty hard stuff, 18th hardest in the world in fact.

Originally Posted by artme

Bob, you and Runge should join forces!!

At those sorts of hardnesses I guess 12th and 16 are relative. Generally they can be described as bloody hard.!!

They're only 100 lbs difference and at 4000+lbs there are almost certainly individual bits of the excelsa that will be harder than the enervia.

Paul. I will hazard a guess and say that you are trying to turn it like a normal bowl, that is from outside in.

It doesn't work that well. You have to go from inside out with a very sharp raked back bowl gouge or a lady finger grind detail gouge.

Rest on centre line (allow for tool thickness) and tool almost horizontal. It helps to drill about a 3/8" hole to just above the depth you want.

If I get time tomorrow I will photograph what I mean.

, I have been trying both outside in and inside out. The inside out seems to catch less and I'm using a bowl gouge with a fingernail grind, it's just taking a long time. I had a hole drilled into it, 12mm and I have gone down to the end of that. I'll drill out some more on the weekend. I thought I would try and get a hole going so I could open up the long grain and reduce the amount of end grain I was cutting.
Thanks for the advice, I'll see how I go.

Paulphot ... potentially funny question. Why have you got the worm screw going into the 'foot' of the bowl???

Funny story...the blank wasn't very square so I couldn't mount it on a faceplate. I decided to worm screw it on the top where I would cut away, then wasn't happy with the purchase I had on the blank so thought I would mount it the other way...that was even worse so I swapped it back. I'll turn the tenon off when I finish and that will get rid of most of the screw hole.
I look at it as a design feature...

Originally Posted by texx

cooktown iron wood ........ Erythropleum Chlorostachys.
shame cos i have a little lump of it and would like to of know where it fell on the hardness scale .

Just don't let it fall on your toe...... it's hard and heavy!

.

This is the way that I do end grain turning.

A swept back bowl gouge or a lady finger nail grind on a detail gouge can be used. These are the angles I have on the detail gouge.

Attachment 148864Attachment 148862

Set tool rest so that tool is almost horizontal and the tip of the tool is on centre. I have the handle down a bit because of habit as a spindle turner.

Attachment 148863

This allows you to start the cut here,

Attachment 148865

I use a rest just long enough to do the job but it doesn't matter. Put the palm of your hand on the outside of the rest and your fingers over the tool.

Attachment 148867

Put the flute of the tool in the direction of cut at about 45 degrees or 20 to 2.

Attachment 148866

Now just squeeze or pull.

Attachment 148869

You can remove a lot of material quickly with this cut but the chisel needs to be sharp and will require a bit of sharpening in hard timbers.

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