Advice on design for #100 osage selfbow

[cool_98_555]

Hello everyone,

I am making another osage selfbow with a slightly cut arrow shelf (8 inch handle), and i'm wondering about a particular design that would work best.  It is 72" long and has no knots with medium rings.  My draw length is 30".  I'm trying to decide between a pyramid design and a parallel limbs design for 2/3 of the limb tapering out to the tips at the last 1/3.  Since this will be thicker in the limbs to accomodate for the 100# draw, I don't want to have too much mass in the limbs that would kill arrow speed and rob performance.  Also, I don't want to make it too wide to have too much mass in the limbs either.  My original plan for this bow was to do 1.5" wide at the fades with a pyramid design with the taper being from the fades to the tips, but i'm not sure this design will work with this type of bow.  Any recommendations for design on this bow would be appreciated.  Thanks!

[bubby]

Personally if i was going to build a 100# bow with a 30" draw I'd build a warbow period, no cut in shelf no nothing

[make-n-break]

I'd be a little nervous cutting a shelf into a 100# selfbow. I usually cut small shelfs into all my bows, but at around 80+ lbs I can really start to feel the the flex in the handle. I might be doing it wrong, who knows, but at that weight I'd personally avoid the cut shelf. You can definitely get away with super heavy pyramids, but I couldn't give you advice on osage dimensions.

I've got a couple heavyweight hickory pyramids between 80 and 95 lbs that are 2" wide for 2/3 of the limb and a straight taper to 3/8 tips on the last 1/3 of the limbs. I've had a handful of monsters break at the fades from too sharp of a transition into working limb. My survivors all have 2.5 inch long fades with a very gradual and rounded angles into working limb.

Also, Pretty much every heavyweight I built that bent full compass/circular broke at the fades from too much stress. It wasn't until i switched to a slightly more eliptical tiller that they lived. I just don't let the fades bend quite as much as I would otherwise.. A good majority of stress is placed on the outer 3/4 of the limb. Don't take any of this as professional advice, I'm just letting you know what has worked for my surviving heavyweights.

I usually use 68-70 inches for a heavy hitter at 28" draw. I'd think with osage you could probably get away with 70 inches for 30 draw.
My favorite bow of all was a 95# hickory pyramid with the above dimensions that shot sooo smooth. It outperformed any other bow I've ever made and would launch an 850 grain arrow scary hard. It was gifted to my brother when he got back from SF training and he still shoots it regularly.

[bradsmith2010]

I would make the limbs parallel,, your limbs wont add too much mass,, cutting shelf I am sure will work,, but with a heavy bow,,having no cut would be stronger

[Del the cat]

Personally if i was going to build a 100# bow with a 30" draw I'd build a warbow period, no cut in shelf no nothing

+1
8" handle is a waste of working limb. 5-6" is plenty IMO...
Cut in arrow shelf is a built in weak point...
just sayin'
Del

[bubby]

It's a proven design for those specs and a classic looking bow to boot

[crooketarrow]

  If it's your 100 osage selfbow. You know whats the best design. Matter fact you've ran out of unsued designs along time ago.

  A 72" osage bow is very close to haveing to much mass. The only thing helping you is it's omly 30#'s,