hazel primitive hollow-limb set?

[stuckinthemud]

Hi Del, thanks for all your advice.  I want 40# at 26", currently she's drawing 45# at 24".  When I heat treat the bow, I am anticipating the draw weight to rise to about 50# - I think that either this is a really good hazel stave, or hazel works really well with this type of design but the other hazel bows I have built have ended up much thicker than this one and been much lighter in draw weight.  I am wondering whether to take a 1/4" off the width, or radius the corners more, or to scrape down the belly, or do a combination of all three.  What is really foxing me is the little bit of twist about 8" in from the left hand tip, I don't want to put a hinge in trying to get rid of it but hopefully if I'm very careful when knocking the weight down I should be able to deal with it.

[FilipT]

Btw, only now I noticed you left bark on, looks really good!

[stuckinthemud]

Not the bark - I stripped that off and then patterned the xylem with a small gouge, but glad you like it

[stuckinthemud]

OK, so I hit it pretty hard with dry heat, got it all nice and straight, draw was 57# at 24".  Have taken it down to 52 - long way to go to get to 40#.  Thing is an inch of the set has come back, so I guess I'll just have to put up with it?

[BowEd]

Say if you want a 40 pound bow don't pull it to 57 pounds.Don't pull it over your intended final draw weight.You might have to tiller it down with a combination of side tillering and belly tillering if you refer to Badgers mass formula to help guide you there.Your doing fine so far but don't pull beyond your intended draw weight no more.

[FilipT]

Yeah, stuckinthemud, that causes unnecessary set. That was my first mistake on my first bow, at the end it had almost 2" of set, because I pulled it more then intended draw weight of 40#.

[stuckinthemud]

OH! So, you chase the weight out to the draw length, not get the draw length and then reduce the weight  

[Del the cat]

OH! So, you chase the weight out to the draw length, not get the draw length and then reduce the weight

Exactly... drawing past the intended poundage is a recipe for set, chrysals, global warming, recession, bubonic plague etc  .
Del

[stuckinthemud]

we can tolerate the plague, but please don't afflict us with Crysals!

I spent the last hour reading all the various threads on the mass theory  I could find - I have no idea how heavy this bow is, but anyone have any idea how heavy it should be - stiff handle, parallel side, hazel, high crown, concave belly, 66" ttt

or should I just go with my instinct and leave the thickness alone and reduce the width - currently 2" (50mm), although Del's wonky hazel bow was also 2" wide

[FilipT]

Give me email and I will send you excel type document with mass calculator. It is a gift from heavens. It says how much grams or ounces bow should weigh at intended draw weight, draw length, length ntn and reflex/deflex.

Then you weigh your bow during tillering every once and a while and you see how much till that calculated weight.

[stuckinthemud]

email sent (hopefully)

[PEARL DRUMS]

Don't forget to calculate that hollow limb design into that calculator.

[stuckinthemud]

Thanks PD, will do.  Maybe if I post my results someone might check them. Am looking forward to getting to grips with the calculator, I think it will make a big difference to my bow-building

[stuckinthemud]

Thanks Stalker, that was really quick 

I have run a calculation which comes out as 15.75oz.  As I understand it, heat treating means a 10% deduction - so 14.18oz.  Should I subtract a further 10% for the hollow limb?

[FilipT]

Can you put photo that shows how yours hollowed limbs look like? I don't know about 10% reduction because of that as I don't completely understand how limbs look like.