85lb Osage Selfbow Layout?

[cool_98_555]

Hello everyone.  I have a beautiful straight osage stave that I can't wait to get started on.  My draw length is 30" and I am aiming for a minimum of 85lbs.  Please note that I am not looking to adhere to the strict rules of the ELB with the rounded belly design in the D shaped cross section.  I am looking at a flatbow design.  I use 30" arrow shafts and I draw the full length of the arrow.  Right now my favorite bow is a 75lb hickory sapwood selfbow made out of a board that is 60" and can be drawn to my 30" draw length but with a bit of finger pinch.  I have thought about the layout for this bow and I have come up with some proposed dimensions for it:

1) Length tip to tip:  70" ( I would like to go shorter if I can, but I want to accomodate for the 30" draw, so I am open to 70")
2)Handle section:  4" (1" above center, 3" below center)
3)Length of fades from handle:  1.5"
4)Width of limbs at fades:  1.5"  (I think 1.75" would be sluggish in this design, but many have told me that wider limbs were good for osage selfbows in flatbow designs)
5)Taper: 1.5" at fades, taper to 1.25" at midlimb, taper to .5" at tips.
6)Thickness:  5/8" parallel limb thickness for starters
7)Arrow shelf will be cut into riser, preferably center-shot.

Knowing my draw length at 30" and my desired minimum draw weight of 85lbs, I am most curious as to the length of the bow, width of the limbs at the fades, and taper design I should be looking at here.  Any suggestions for these dimensions in particular would be very much appreciated!  Thank you!
-Dustin

[adb]

You want to shoot an 85#@30" flatbow? What do you want to shoot at? What are your plans for it?

[Newindian]

There is a lot there I can't comment on, but I would defiantly say lose the shelf

[adb]

I totally agree.

[toomanyknots]

I say make the bow however you like your bow, it's your bow, you should make it how you like it. That said, I think with your designs you could go a good deal shorter and still make 30". I would also go with at least 1 3/4" fades, unless it is some good dense osage. You might end up with somewhat of an oval cross section which ain't too bad of a thing really.

[cool_98_555]

Hello again everyone.  Thank you for your replies.  I knew something would come up on the draw weight.  To be honest with you, I like making high draw weight bows.  First, it gives a challenge, and second, I can pull 85# at 30", so I would love to make a bow of my own to those specs.  75# is not a problem, and I like shooting heavier arrows,...it is just a thrill for me. 

The width of the fades I have been struggling with in terms of osage, especially with the dimensions I want to go for with this bow.  There are several people that tell me I should go with 1.75 or 2" because osage apparently likes the wide flatbow design, and then there are others that say that osage is a very strong wood and if the stave is of good quality it is acceptable to go to 1.25" with a thicker profile to start the tillering process.  I would also love to go with a shorter length, like 66" if it will safely accomodate the 85# at 30".  I have also heard that it depends on how wide the limbs are in this case, so I'm not positive with the 66."

[toomanyknots]

You can go 66", but 68" would be better. Especially stack wise, the higher the weight, the more you notice stacking at the end of the draw. (and some people might say it is pushing it, but I won't with good tiller and a good osage stave) If the wood is good enough, you can go with 1 1/4" wide fades, but if it ain't the best osage, especially with the length of the bow, the cross section is gonna be a little deep. It is hard to answer these precise questions, because every piece of wood is different, and every bow is different for that matter. Alot of making bows from staves, and making bows in general, relies on "going by feel". If it feels like it is gonna make 90# or so at 30" (like a 80# at 28" bow) when floor tillering, than your good, etc. If it feels like it is gonna make a 120# bow when floor tillering, then you might wanna decrease the fades a bit, etc. Maybe add a couple inches back onto the bow...   ( j/k). Floor tillering always feels a bit heavier than your goal weight though, after making a couple you will get a hang for estimating the floor tiller to get the weight you want, shoot for more than you need.

[cool_98_555]

Toomanyknots, thank you for your elaborate reply.  68" is a great length to start with, and if I want to, I can always pike it later.  The stave is really almost flawless, so I think i'm going to go with 1 3/8" wide at the fades.  The only issue that worries me is the arrow shelf.  At 1 1/4" wide or 1 3/8" wide, it is difficult to picture the bow having a center-shot arrow shelf, even if the riser is at least 1.5" thick.  As a general rule, how thick does the riser need to be and how much wood do you need on the other side of the arrow shelf in order for it to be safe to cut a shelf into the bow?