Crossbow prod(bow)

[TMM]

Hey, i am in the process of making a crossbow- got the stock and trigger mechanism all done(and it looks and works damnfine if i do say so myself)

the first try with a torchcut leafspring had a ~100lb pull and shot an arrow 20 feet... and the laminated ash prod is 1) delaminating 2) too heavy 3) bent/laminated wrong(short lamination on the outside)

So- time for a third try. how would a steam-bent Hickory prod work? is there a certian part of the log i should get for optimal performance?

~TMM

 

[carebear]

How heavy is your bolt? If it is too light, the acceleration from the bow can either not be transferred properly to the bolt (won't fly right), or, like dryfiring a trad. bow, can rip itself apart.

I have no idea how to figure out proper bolt weight other than trial and error, but I assume too heavy is better at first than too light.

 

[Cadwallader]

Having made lots of hickory bows I can maybe help a little. The most important thing is straight grain, and especially unbroken grain on the back (what you ideally want is individual wood fibers on the back running uncut from tip to tip). For this reason lots of people make wooden self-bows from a split piece of a log (using the face of the tree right under the bark as the back of the bow) rather than using milled lumber (if you have a dealer with lots of hickory and he doesn't mind you digging around you can definitely find usable wood). Hickory sapwood is as strong as heartwood given equal density (some wood is just going to be denser due to growth conditions, species, etc., and therefore stronger).

If the piece you need isn't too long or wide you can just buy ready-made pick handles - guaranteed to be pretty good quality and straight grain.

Hickory steams okay, but you may have to do some trial and error on the length/severity of your recurves, as they increase the strain on the remaining straight limb by a whole lot, and even if you don't break limbs you'll put extreme set into them (permanent deflection that robs you of pull weight and efficiency).

I know that medieval crossbows mostly had laminated horn/wood limbs, which makes sense because at short limb lengths plain wood has a very tough time of it.

 

[TMM]

carebear: just a medium weight bolt i guess, double-bladed broadhead, ~16g. steel- birtch shaft, fletching...

Cad: my dad's a woodworker, he said that the guy might even just let us get scraps for free. so i bet we can do a few tests...

~TMM