Bows by the numbers - modelling a bow before cutting timber

[yeoman]

This week a friend and I made a pair of bows on the basis of some mathematical modelling.

I modelled a pyramid bow using non-published, aggregated/averaged data from some white oak. I used a working strain that should theoretically have induced about an inch and a half of set. Between us I we made two - one 50 lb at 26 inches and the other 40 lb at 26 inches.

I haven't made exhaustive measurements, but the early indicators are that the final dimensions (thickness) are within 1 mm of the projected dimensions. You can see from the photos that we didn't get the finished bows to match the projections exactly, but they're pretty close. And the average set of two limbs is 40 mm - just slightly over 1.5 inches. As predicted.

[Stickbow Hunter]

Good work and very interesting. I know Dennis La Varenne was always interested in your mathematical modelling. I have the last bow he ever made, a beautiful Yew flat bow.

Jeff

[yeoman]

That should be a national treasure.

[Stickbow Hunter]

That should be a national treasure.

Yes very special. I have a number of his bows etc that I would like to see go to a museum but sadly the national bodies don't have one as yet. Hopefully one day.

Jeff