Draw weight

[Pappy]

What Mike said, all I want it for it to gain weight pretty even as you draw inch by inch,then it will be a smooth bow,obviously the heaver you want the bow to wind up the more per inch it will gain,most bow I make are in the low 50's and gain
2 to 3 lbs per inch. EST. 
   Pappy

[PEARL DRUMS]

I had a feeling I should have put 5-6 disclaimers in there to cover ALL the bases rather than just 92.421% of them.

[Pappy]

 
   Pappy

[Del the cat]

They tend to be pretty linear and it's easy to do the arithmetic...
BUT The thing you have to remember is draw length isn't draw length!!!
10" 'draw' is really 10" minus the brace height. So your 10# at 10 " isn't 1# per inch increase it's really 2# per inch!

This blog entry may be of interest! It explains why a lady shooting a little 35# Hazel bow was shooting as far as some guys with a 50# longbow!
http://bowyersdiary.blogspot.co.uk/2013/07/draw-and-poundage-arithmetic.html
But even this is a simplification.
You really want two figures say at 10" and 20" draw you can then subtract the lengths from each other. Subtract the poundages from eachother divide the poundage by the distance and get a reasonable figure.
E.G 15#@10" and 35# @20" would give (35-15)# over (20-10)" which is  20/10 which is 2# per inch
Del

[twisted hickory]

Its a spongey piece of junk.

Sure but the 2-3 pound is more of an average not every bow is the same 2-3 pounds an inch

I have only made 12 bows so far and as an average it is 2-3 lbs per inch. If it's less than that or more something is wrong with tiller/design. towards the end of draw length/weight it may gain like 3.5 lbs per inch on the last inch. This is also called stack. how much  a bow gains poundage depends on how much wood there is and where it is at on the limb as well as lenght of bow and lenght of draw. Lots of variables here to account for. Generally speaking ya want 2-3 lbs per inch.
Hope this limited knowledge helps.
Greg

I really don't want to argue about it but I disagree your saying tht a 120 pound warbow is still only gonna pull 2-3 pounds an inch ? And that a 20 pound bow is gonna pull 2-3 pounds an inch ? I don't think so. And saying that if it doesn't pull 2-3 pounds per inch then it is the wrong design/tiller is just silly

Got the proof setting in my corner of shop. Tiller one really screwy and pull it to full draw you will see what I mean. Leave the inner limbs way to stiff and see what happens It will stack bad and gain more than 3 lbs per inch the last 4 or 5 inches. 3.5 lbs per inch over 30 inches = 105 lbs so its ABOUT 3 lbs per inch. No one claimed to have some formula set in stone. If its a 400 lb cross bow of course it's not going to be 2 lbs per inch.

[Buckeye Guy]

I think Del has it right ,but all this math is making my head hurt!
Think I will just go make a bow , it is more relaxing and way more fun than all this math !
Have fun !

[Joec123able]

Its a spongey piece of junk.

Sure but the 2-3 pound is more of an average not every bow is the same 2-3 pounds an inch

I have only made 12 bows so far and as an average it is 2-3 lbs per inch. If it's less than that or more something is wrong with tiller/design. towards the end of draw length/weight it may gain like 3.5 lbs per inch on the last inch. This is also called stack. how much  a bow gains poundage depends on how much wood there is and where it is at on the limb as well as lenght of bow and lenght of draw. Lots of variables here to account for. Generally speaking ya want 2-3 lbs per inch.
Hope this limited knowledge helps.
Greg

I really don't want to argue about it but I disagree your saying tht a 120 pound warbow is still only gonna pull 2-3 pounds an inch ? And that a 20 pound bow is gonna pull 2-3 pounds an inch ? I don't think so. And saying that if it doesn't pull 2-3 pounds per inch then it is the wrong design/tiller is just silly

Got the proof setting in my corner of shop. Tiller one really screwy and pull it to full draw you will see what I mean. Leave the inner limbs way to stiff and see what happens It will stack bad and gain more than 3 lbs per inch the last 4 or 5 inches. 3.5 lbs per inch over 30 inches = 105 lbs so its ABOUT 3 lbs per inch. No one claimed to have some formula set in stone. If its a 400 lb cross bow of course it's not going to be 2 lbs per inch.

Yep

[twisted hickory]

I think Del has it right ,but all this math is making my head hurt!
Think I will just go make a bow , it is more relaxing and way more fun than all this math !
Have fun !

Yep gotta try to patch some frets on a hickory bow.

[medicinewheel]

Damn pearl, that actually made me laugh outloud

It's not funny, it's true.

[BowEd]

For me it's always the 5# every 2" estimation on my bows after you've made enough bows to know your tllering results on your bows[45-60 pounds].Now I like knowing this because of heat treating in tiller bows early at low draw length[white woods,avoiding crushing belly wood]and putting together composite components onto a lighter weight in tiller bow to get close to my draw weight at 28".It's a very handy thing to know in bow making.

[Don Case]

If two bows of different wood but the same draw weight(say 40#) shoot the same arrow, will it go the same distance/speed? I'm guessing no, but I've got no good reason. What other factors enter into this?
Thanks
Don

[Weylin]

there are too many other factors in play but I'd say that the type of bow wood is one of the least.

[SLIMBOB]

If the unbraced profile on those two bows are the same, then the arrow speed will be the same, or very very close regardless of them being 2 different woods IMO.  One say is Osage and the other Ash, to get them both pulling the same weight and maintaining the same profile, the Ash will take more wood, i.e. wider than the Osage.  That is the modifier. 

[Don Case]

That surprises me. If that's the case, then why is there so much discussion about which wood to use? Workability?
Don

[SLIMBOB]

Bad example really, you see Osage is magic!  So use any other dense wood and the example is in my estimation accurate.  The joke illustrates my answer to your question.  People have a favorite wood.  Maybe because it is readily available in their area, or its density, or color or any other attribute they find desirable, but if you leave Osage out of the equation, wood is wood.  Its variability can be greater within a species than it might be to another species.  End of the day, unbraced profile tells the biggest part of the story, and you have to treat different woods differently to get them to achieve the same profile.  Once you have, I think they will behave similarly.