Red Ironbark

[hellier]

I got some wood yesterday...2" x 2" x 80 ", red ironbark....from Proserpine Mill...I reckon I might get two self bows out of it. The Holmegaard specs I've got are for a bow that has it's handle at dead centre, I'm supposing then that the top limb will need to be longer to bring the arrow to dead centre...how much longer I dunno.....help. It's basically gonna be 65" between the nocks, unless I should change that too...I draw 28"...any ieads..Glenn ??
Hellier :?

[tracker]

A thread with some info on tillering a Holmegaard style bow.

http://www.ozbow.net/phpbb2/viewtopic.php?t=2648

Mick.

[Glenn]

You can do it both ways Hellier, if the bow handle is dead centre and the limbs are of equal length then normally hand placement on the handle is the middle finger of your bow hand is the centre of the bow and the arrow is shot off your index finger. If you are shooting a bow with equal lenght limbs then you will need to make the top limb stiffer because you string hand is further up the string you are putting more pressure on the top limb.
If you want to get the arrow in the centre of the bow the top limb will have to be longer than the bottom limb. To get this measurement measure from the centre of your middle finger to the top of your index finger which will be around 30mm to 35mm and that is the measurement you lengthen the top limb. Hand placement on a selfbow is middle finger of bow hand is placed on the middle of the handle so you don't upset the tiller of the bow. On a bow with the shorter bottom limb the bottom limb is stiffer than the top by 1/8" to 3/16" the reverse of the bow with the equal lenght limbs.
The Holmegaard is a very good selfbow design especially for our hardwoods, I made one out of grey ironbark that I have used for hunting, I like it a lot, it only holds 1/2" of string follow. I made mine with half sapwood and half heartwood...Glenn...

[hellier]

Thanks for both of those...yet to read the link download but it looks good. Glenn I'm not sure if this wood has much of either heart wood or what...I may have to run it through a planer thicknesser just to get a better idea of it's structure...it's pretty much rough sawn at the moment. I noticed that the shape of your bow ( the one you've photographed on the hood of your car ) has much finer fades ( ? ) than the diagram that I'm working to...that said the diagram is not to scale...so I guess I'll try and follow your example and make all those transitions smoother...yours looks better too!