Board bow thickness and width

[Wolftrail]

Building a simple maple board bow, backed with a 1/8" lam of maple.  Its 7/16"+ thickness and 1 3/8" at the fades how long should I make it to achieve 42#.   I like to keep it  around 65-66" NTN.

[Roy from Pa]

66

[Pat B]

x2

[Wolftrail]

Thats what I thought as well,  2nd. and 3rd. opinion confirms that.

[YosemiteSam]

After a bunch of errors, I'd start long & tiller it to whatever it comes out being.  Then, if it's too heavy, you can use a pocket knife to gently scrape away a little extra material & bring the weight down.  And if it's too light, you can shorten it a bit.  I'm pretty new at this so I like to find ways that I can correct a mistake later rather than plan on getting it right the first time (because I rarely do).