Some thoughts/advice on this layout

[monterey]

Here is a representation of an oak board molly that I'm contemplating.  Not a very good representation so hopefully it will be understandable.

This represents 1/2 of the bow.  Finished bow would be 72" long.  This shows one limb from the center of the riser section to the tip.  Riser is not shaped, just shows as a rectangle.

Am wondering if maybe a 17" riser is too long?  How about the ratio of lengths of the working limb (pyramid) to the lever?

Any other thoughts you might have?

 

[blue_beast_66]

was really hoping one of the big boys would have commented on this one

[John Scifres]

I've never made a "molly".  A 17" riser would be very long for any of the selfbow designs I have made.  Mine are generally 10" max.  What is your goal in making it so?

[monterey]

John, Was thinking of extending the length to ease full draw string angle.  Was having doubts about the length and now you have me doubting even more!  If I leave the levers at their present length, shorten the riser and add the length to the working limb maybe that would be wiser??

Any and all suggestions greatly appreciated!

[PEARL DRUMS]

50/50 is a good lever to working limb ratio. I have a 61" osage molly that is 40/60, but that's osage and not a red oak board.

[John Scifres]

Don't doubt yourself on my account.  Jim Hamm used to talk a lot about longer risers to decrease string angle so there is certainly merit in your thinking.  I would try it and see what happens.  Test it against a shorter riser and see what you get.

[LittleBen]

I'd also consider keeping the outer portion of the working portion wider.

I'd mark it out like this 2.5" wide at the fades, the draw a long tapering straight all the way to the tips, like you were making a pyramid bow with a "0" (Zero) width tip. Then mark a line where you want to start the levers. This way you're working section will taper so it'll basically be an even thickness in the working portion.

You'll have say 2.5" at the fades and 1.25" wide or so at the outer portion of the working limb section. Then make the levers whatever thickness/width you were intending ... Just a thought. Never made on of these. Been thinking of makign one, but almost a flightbow style limb, just not as stressed.

[monterey]

Ben, I like your design concept and consider it well worth trying.  In fact, on my next molly I'll do just that.

For this one, am going to reduce the riser section from 17" fade to fade to 12" fade to fade and put that extra length into the limb leaving the levers as they are.

Can see how this is a difficult design to work up with boards.  The difference board to board could be misleading.  Next go around, am going to follow your suggestion and do some chrono readings while gradually bringing your design concept around to match mine.  Draw weight won't stay the same, but fps per lb of draw weight should tell us something.