Hi All,

I started making crossbows years ago so I could find out about them as there was so little reliable information. As part of this push, I try to disseminate what I find out using originally this site and now You Tube as well, where I have a channel with videos on such subjects as how far does a windlass bow shoot and how a two Axel crossbow trigger works as well as sword related bits and pieces.

This particular video looks at 9 different ways to span a crossbow and how powerful a bow you can span using that system and what the ratio of mechanical advantage of the system actually is. https://youtu.be/2IdfmaC_t-Q

Hopefully it will be useful to some of you.

Tod

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Note to everyone the video is well worth taking the time to look at.

Tod, really informative about the relative draw weights and leverage advantages of the different ways to span the prod.

I was really surprised to find out that the cranequin leverage ratio was better than the windlass as far as how heavy a draw it could manage.

As to the 1:1 ratio when not using a system with a leverage/mechanical advantage I think your numbers are in the ballpark, but some hugely strong guy might be able to span a bit heavier ..... If the guy was the size and strength of " THE MOUNTAIN " from the Game of Thrones ...... ;) :lol:

But then that guy might be able to draw a 300 pound longbow if he trained for it a little bit ..... :eek: :lol:

Very good video, well presented and very informative and entertaining.

Tod has made at least a couple bows that use a gaffle like that. His opinion is that they are less effective and less easy to use that a got’s foot, if I recall, if not, I hope he corrects me. I can’t measure the gaffle of course, but it looks like maybe a 4 to one advantage? A goat’s foot is interesting in that if has a variable advantage that is quite high near full draw.

I’m sure super beefy guys can draw more directly. But one advantage of a cross bow with a good spanning device is that huge beefy arms aren’t necessary.