Side tillering...removing mass question

[straightarrow]

Heys guys,

Working on a bow that might be a little overbowed....I still have to weigh it. I don't know much of anything about side tillering. If I remove wood from the sides will it change the draw weight of the bow??? Right now I am 25#@14" and I am shooting for 55#@28". I did the mass formula and I was around 23 oz. I will repost when I weigh the bow?

Thank You Jon

[bubby]

is it a pyramid bow, on a pyramid you would remove material from the side, other styles mainly remove from the belly, how thick, wide, and whats the baisic design of you're bow

[straightarrow]

Its a pyramid style bow....non bending handle...less then 1/2 thickness....1 5/8" and the widest tapering to 3/8" at the nocks. Its 69" long tip to tip and the wood I am using is Hop Hornbeam.

I got the bow tillered out now to 28" and its 55#. It weighs 21.5 oz. I'm gonna recalculate the mass principle again, but I think I'm gonna be good.

But to answer the question...Does side tillering lower draw weight??? I can't seem to sort this out in my mind....but I'm thinking yes???

Jon

[macbow]

Hi, yes taking wood from the side will reduce weight. If I remember correctly the ratio is in the 8 to 1 range. That is removing wood from the thickness will be 8 times removing the same amount from the sides. On a pyramid bow removing on the wider portion would have more effect. Along the same lines trapping, removing wood on the sides at a angle is also effective.
Ron

[jwillis]

Jon, this thread from a few days ago should really help...

http://www.primitivearcher.com/smf/index.php/topic,22061.0.html

[mullet]

 Yes, it will reduce weight. Don't try to over think what you are doing, if you remove wood you are reducing  draw weight. I'm tillering a bamboo back and belly with osage as the meat. I'm removing only wood from the sides and will tweak it with heat when I get close. Like Ron described, I'm trapping it. You just have to be carefull and remove the wood slowly and equally, so you don't make one side of the limb weaker. This will cause one to twist to the weaker side.

[straightarrow]

Thank you for your replies fellows. Gonna check out that thread...jwiilis. I did the mass principle formula again and got 24.75 oz and the bow weighs 21.3 oz. I still got to round the edges and do the final sand. This whole mass thing is new pretty new to me. I took a friends advice at the begining of my bow making and that was "just make a bow and don't worry about speed" Now that I have quite a few under my belt I am ready to advance my skills...Thats one thing that I am really enjoying about this hobby...Its constant learning. There are some great guys on here and I appreciate their knowledge!!!

Jon