Grey Myrtle Flat Bow

[GraemeK]

Hi Folks

Below are some photos of a flat bow I am working on. It is 70" long and about 1.5" at the fades and a little less than .5" at the tips.
It is made from a small diameter log ( about 6" ) so it has a fair bit of crown on the back. It is an unusual timber from a tree that never gets much bigger than this one. I has an S.G of 1.4 and is exceptionally close grained and is stiffer than any other timber I ever worked with. It is not used for anything I know of these days but was commonly used in the 1800's for the spokes of wagon wheels.
I think it has great possibilities for a bow timber but I have found that it is not possible to heat bend it -- I have tried it green and dry with steam and dry heat at temps up to ignition but just will not bend  -- it does like to crack from the heat though.
My opinion is now that to achieve a nice bow you really need a stave that needs no adjustment but I have started this one and I would get it shooting. The problem is that the limbs junction the handle at opposite angles -- in other words right limb in the photo is basically reflexed and the left is deflexed. Since I can not correct this I have been attempting to tiller  so it bends evenly despite the angle problem. This seems to be working but I can not help but think that it is not such a great idea. ( not that I seem to have much option)
Any feelings about this?


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[El Destructo]

Go for it Graeme....Looks to me like you are working it it fine...just remember like I have heard here a thousand times....Patience makes the Bow...dint get in a hurry...and work the wood good after every time you remove any wood to get a true look at the new bend....I think it is going to be Nice!

[welch2]

With one reflexed and one deflexed limb, lot's of guys tiller like you are ,concentrating on the full draw profile. Seems to work for them.

I tiller bows like this ,like I would any other character bow..... I strive to have each limb ,and parts of each limb, bend the amount a straight limbed bow would.  Becuase to tiller so that the full draw profile looks like a straight stave bow, means you have made the reflexed limb quite a bit weaker than the deflexed limb. Sometimes this means shortening the deflexed limb.  Kinda like a yumi or a Andaman Island bow. 

I've never heard of grey myrtle ,where does it grow?

Ralph

[GraemeK]

Hi Ralph

Grey Myrtle ( Backhousia myrtifolia) is an Australian tree that grows along creek lines in coastal areas. It is often the most common vegetation in these areas but most of the plans that you see ate small bushy shrubs. When you find one that has developed into a tree with a 6" trunk and cut it you can see from the growth rings that it is about 150 years old. I have often wondered why most of the plants seem to stay as shrubs but maybe the deal is that many seeds germinate and grow for a few years but do not survive long enough to become a tree because of drought or fire or something but these are quickly replaced by more seedlings so you tend to see small plants not trees.

What you say about the result of tillering to the same shape as a bow with a straight stave ( one limb weaker than the other ) is exactly what I am concerned about. It seems that I will end up with a bow that looks nice at full draw but will not work well.

Graeme

[welch2]

So tiller it out like I do. Watch each limb carefully ,and get them to bend the same amount(as in inches of movement from thier unstrung positions)
   So that at full draw the reflexed will appear to be bending less than the deflexed limb, but in fact the limbs will be moving the same amount...
   If you also shorten the deflexed limb a couple inches , they will appear more even at full draw, and brace too.

Ralph

[Rich Saffold]

Graeme, your bow is looking good. On bows like these I'm usually shooting them before making any decisions about shortening a limb. Your tiller looks rather symmetrical at this point so the difference in these limbs should be less as you work on them. The higher strain on the reflexed side can balance with the less strain on the deflexed side..

By having even length limbs, I don't make one the upper or lower limb until I have shot it and the feedback from the bow lets me know  which way it shoots the best..

1.4 sg. Thats the kind of wood I look for

Rich

[GraemeK]

Hi Rich

I think you are right, the difference is reducing as I tiller it further. I think the reflexed limb is taking a bit more set and evening it out. With a bit of luck it will be just enough to give me a nice amount of positive tiller when I have finished. If not I will adjust the lengths like you and Ralph suggest.
I really do like the wood -- but I have to admit I am biased towards high density woods -- even when the lighter timber is good and stiff it sort of seems insubstantial. Crazy way to feel I guess given the mass per pound of draw weight is more or less a constant.
Still we all have our preferences.
I have a few more well seasoned staves that are a perfect shape with a couple of inches dried in reflex and I am going to try a heavy ELB from one of them. It would seem from this bow that you would not need much wood to give you 80 - 100#.
Not sure what I am going to do with it if it works since my shoulder problem means that I am shooting lighter and lighter bows every year

Graeme

[Pappy]

Looking good to me so far,we get some Hickory like that sometime ,that will do that at the handle and if you try and take it out it will split up on the belly side of the handle,so we just go with it as is
and they usually work out fine. Slow and easy is the word.
   Pappy