crossbow prod

[Frode]

Hi all,
I just read through the excellent build a long on the crossbow stock and some similar posts, but I didn't see any information on designing a wooden prod.  A friend and his two sons are looking into building three crossbows (14th century design, I don't know more than that yet), ranging from "don't care so much what it looks like as long as it shoots safely with period-esque mechanisms" to "full on reproduction piece".  They will be building the stocks and other working parts, so I don't have to worry about that for now, but I have been asked to help out with the prod.  They are thinking 36" nock to nock, 80# @ 18" (which seems a bit light to me, but...).  They would prefer a wooden prod (period authenticity, no metal working facilities, worries about catastrophic metal failure, and glass is just wrong).
Can anyone point me to any information on the subject?
Thanks,
Frode

[M-P]

Frode,  You might check this site for past posts concerning crossbows.   I posted one a couple of months back, though mst point out that one arm of the prod delaminated since.   The Book of the Crossbow by Galway shows a rough diagram of the construction of a horn bellied prod, though I doubt its veracity.  At least one of the posters here has built two peice prods of non laminated hickory, and 'Orcbow' posted one with a wooden prod.  From my limited experience, wooden prod construction is little different than making a small very heavy bow.  The hard part is getting a set up that can bend the bow and let you see how your tillering is doing.   Ron

[kiltedcelt]

Most of the wood prods I've seen on this site and some others are way too long to be period looking at all. Those bows will work, but to my eyes they always look a bit unwieldy because the prods tend to be much longer than real period crossbows because the longer prods guys are making are the only way to get a high draw weight and a stable prod. Something else to consider as well is for just playing around you can make a decent wooden prod but the draw weight doesn't have the power of a similar horn/sinew prod or steel prod.  If you're wanting to make some bows that will just shoot - looks don't matter - (your one kid wants this), then you can follow the design of the some of the bows that have been posted here. For the other kid that wants something very period looking, it'll have to be a short prod and it would need to be horn bellied and sinew-backed. Or, you could make everything else yourself but the prod. If you search back through the posts you should turn up a crossbow I made. I think it's titled "Medieval Crossbow" or something like that. Anyway, my bow was made to look like a late 1500s sporting crossbow with a steel prod. Feel free to PM me if you want some links to check out or want to know where I picked up my parts.

[Del the cat]

The short answer is they didn't use wooden prods at that time.
Wood rapidly was overtaken by composite (horn & sinew) which was then overtaken by steel.
A wooden prod built to look like a composite one one probably snap.
Maybe laminated bamboo, made thiner than a genuine prod could be made to look right.
Failing that, a wooden prod made to the dimensions of a steel one would be effective, the flared nocks would be easy to fashion too, you would also get a manageable and safe draw weight.
The usual trick of making a prod from a car leafspring ends up giving a prod which which is v strong but looks too thin, e.g My repro light sporting bow 275# draw weight, here are two links to a site where I wrote up a recent refurb of the bow which may be of interest.
http://cr4.globalspec.com/blogentry/9196
http://cr4.globalspec.com/blogentry/9255
Del