Primitive Archer
Main Discussion Area => Bows => Topic started by: GraemeK on February 02, 2008, 06:58:45 am
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Hi Folks
Thought you might be interested in the bow I am currently working on
It is made from a timber called " Brigalow " which is an Acacia (or Wattle) its botanical name is "Acacia harpophylla"
It is a tree that only grows in a restricted area in northern Queensland its habitat is about 100miles long and 50miles wide and the majority has been cleared for grazing land so it has become fairly scarce and it is protected in the native forests where it still grows.
It is a dryland tree growing in areas with aprox 10 - 12" of rain per year and when mature at about 100 years of age will reach about 50' tall with a trunk less than a foot in diameter. It has been cut as a furniture timber in past years but its small size and scarcity have meant that it has not been commercially used for the last 80 years or so but it was widely used as a bow timber in the 1920 to 1950 period. It has an S.G of 1.3 for the heart wood and .9 for the sapwood.
I know of no-one who has made a bow from this wood in recent years so all I have had to go on was rumour and a few old black and white photos which showed mostly narrow deep section target bows from the 1940's
The first problem was getting the timber since it is 900km from where I live so I had to persuade my wife that a nice road trip to central Queensland to cut down a tree was a good idea. ( Proves anything is possible )
Second problem was that I found that even with a deep kerf splitting the log produced nothing but fire wood -- just will not split without destroying the log. Resorted to sawing the logs into quarters since talking the wife into a second 1800 km trip seemed like a long shot.
So having waited till the staves stopped loosing weight ( 9 months )I decided I would take one of the less perfect ones and try a sort of generic flat bow to get a feel for the timber.
Started by roughing it out 40mm wide ( about 1.5" ) and reducing the sapwood to 8mm then left it for a couple of weeks just to check that it was stable.
Then decided that at 40mm wide it would end way to thin by the time I got it down to the 50# that I wanted -- and also that the heart wood would be almost gone by that time so I have now reduced the width to 30mm. It still seems like it is 80# or so when just bent while floor tillering it but I think I will be able to make it work at this width.
Graeme
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Beautiful looking bow. The contrast of the sapwood and hardwood is really pretty. Keep us updated. It's nice to learn about differnet types of woods from other parts of the world.
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Very nice looking wood. I hope it works well for you. The bow is turning out well also
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Great job GraemeK. I am glad you found such beautiful wood to work with. I cant wait to see the finished pics. I love the way you accentuated the fades. Justin
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Oh my that is some beautiful wood. I can't wait to see the finished bow.
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That really is a beautiful wood, I can't wait to see the finished product. Looks great what you have done so far. Steve
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that looks awesome
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.........GraemeK--------------luvs ta see foks using unknown woods. Will be very interestin' ta see how it comes out ...........oh yes nice bow so far...........bob
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That is some beautiful wood. Really like the look you came up with for that bow. Good luck.
Dale.
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Thanks Guys for the kind words
It is beautiful wood and it has a wonderful reputation as a bow timber. It will be interesting to see if it can live up to it.
One of the things that I was surprised by was that it is really nice to work despite being very dense .
The shape of the handle and fades was a bit of an accident really -- just sort of happened when I decided to reduce the limb width. Funny how interesting ideas are often the the result of chance rather than planing.
Below are a couple of photos of a larger log that I cut to make handles out of. The dressed timber really shows off the grain.
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Graeme, Great thread! ;D especially since I'm quite sure there are a few of those trees where I live..1.3 sg..ya thats what I like seeing, and its so beautiful! I have used other acacias and they were lighter but shot well..
Your bow looks like it will really perform..I'm gonna shop for one tomorrow before the game..Thanks for the tip!
Rich-so many trees so little time ;)
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Hi Rich
If you are trying to identify the Brigalow maybe these photos will help.
They are taken at our local Botanical Gardens not where I cut the timber in Queensland
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That wood is beautiful. I'm thouroughly facinated by woods from across the globe I have never seen. I hope you are able to fashion a bow from it that shoots well my friend. Danny
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Look's nice! I do like a Bow with a Sapwood back .
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Hi Loki
I think the reason that the timber was tried originally was that the finished bows look a bit like Yew -- all the photos of old bows that I have seen have been in the ELB style
Graeme
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Thanks again Graeme! Ya there's some of those trees at the local university, an downtown near the wood shop I work at..Our area has almost every Australian tree species..Over 200 or so, and there's over 1000 non-native species here. I actually thought this tree was a eucalyptus, and I haven't had the best luck with this species so far. But I know this is going to change..
I can understand why you did all that driving.
Rich
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Hi Rich
The trees near you may be Brigalow but there are 960 Acacia's and I can think of a dozen or more that are had to distinguish from Brigalow except by careful study of both the flowers and seeds and comparison to a field guide.
If you cut an Acacia that is one of the larger tree species there is a good chance that the timber will be dark heart wood and light sap wood as this is common in the Acacia's but they vary greatly in physical properties. A good example is Acacia melanoxylon ( Tasmanian Black Wood ) which has similar shaped leaves and general appearance and typical two tone timber but only has an S.G of about .6. I have tried it as a bow timber because it is common but it is only marginal as it takes a lot of set and splits badly.
Still if what you have available has a good S.G it should work to make a good bow.
It is interesting the experience you have had with the Eucalypts.
I am not surprised -- even in Australia people have difficulty and the main reason is that there are 700 species which often grow intermixed rather than in defined forests. This means that cut timber is rarely correctly identified and even if people cut it themselves it is often incorrectly identified. The problem that this causes is that the suitability for bow timber varies from complete rubbish to some of the best woods in the world.
This would be difficult enough but is further complicated by the fact that within any species the physical properties vary greatly with the conditions and location of their growth.
The Eucalypt that I think is by far the best is Eucalyptus paniculata ( Grey Iron Bark ) but I have found that it can vary in strength by as much as 50%. This is not as terrible as it seems since even at its worst it is still a strong and resilient bow wood but it means if you use the same dimensions that work for the stronger material on the weaker wood it will probably fail and in Eucalypt this will be a catastrophic failure not a case of excess excess string follow.
Graeme
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Hi Graeme,
After trying spotted gum and finding it disappointing, I have often wondered about brigalow. John Clark from Ausbow Industries has been selling brigalow logs for about ten years now and if fussy old John considers it to be worth making a bow out, then it must be good!
Another wood I have heard whispered about is Red Almond; Alphitionia excelsa. I know that some aussies were making some hard shooting high draw weight elb's out of this wood a while back. To find out more about it, try tracking down Glen Newell, sometimes he posts on the Ozbow forum.
Also, I have read that in queensland grows a small vinelike shrub called 'Cocksthorn spur', genus; Maclura. Like its brother, osage, it has yellow timber that has been used as a dyewood, large inedible friut and thorns. Could be promising.
Reagrds James
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Hi James
I am familiar with Alphitonia excelsa -- it is often called Red Ash locally. I cut a large tree about a year ago that gave me three logs 2m long and 300mm in diameter. I have tried one stave that so far has not impressed me, it has a low S.G and does not work nicely.It is going to have to have exceptional elastic properties to live up to its reputation. Also you need a nice straight stave because it does not like to be heat straightened since it likes to form cracks.
Below is a photo of the timber -- it is about the best log you are ever going to get so I figure it should be representative.
Graeme
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Nice haul,that some beautiful looking wood.Looks like the bow is coming along nicely also.
Keep us posted. :)
Pappy
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Thats a good looking shed you got there!!
Disapointed to hear about the red Ash, I found one here in NZ and was looking foward to poaching a piece. That'll teach me for trusting Aussie stories :) :)
That brigalow bow is looking good
James
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Great haul. That stuff is sharp lookin. Good luck. :)
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also, thats a nice looking osage log you cut as well.
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Hi James
I would not say I had given up on the Red Ash --- I am just reserving my judgment till I have a working bow that I can try.
I am probably a bit biased towards denser timber but obviously there are a lot of advantages to low limb mass if the wood is also highly elastic.
I will persist till I have a nicely shooting bow since I have seen a couple made from Red Ash that I was impressed by.
The Osage Log is nice but I did not cut it myself. A guy from the OZ Bow site found it while hunting along the NSW /QLD border and I picked it up from him during the same trip. I have put It aside till I feel inspired enough to try a all wood static recurve.
Graeme
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Graeme, I'm meeting the arborist tomorrow at the local Botanical gardens to ask him a few questions, and this will be one of them..Like you mention a lot of them are very similar, and he will help me get the right ones..
Rich
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Gosh darn it my wife saw that bow , now she wants me to build one because thats pretty , you guys are killing me .
sean
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Hey Sean
I wish the only jobs I needed to do to stay in the good books was make a bow or two.
Sounds like my kind of wife.
Graeme
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Hi Pappy
Yep I am real pleased with the timber and the bow is turning out nicely. I think this may the best bow from Australian wood that I have worked on.
It is good to be making some wooden bows again. I have been busy setting up the equipment for a guy who is starting a bow manufacturing business -- mainly take- down recurves and laminated long bows --- it has been interesting since I got to combine my bowmaking experience and my engineering background but it is a bit much like any other manufacturing process rather than bow making.
Still it has kept me busy long enough for some of the interesting wood that I have cut to dry enough to work on.
Graeme
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Looking good to me,good to see ya back at it,hadn't seen you on in a while.Did your
health problem turn out OK.hope so. :)
Pappy