multi-lam bows

[LESKEN2011]

I have made a good many bows with all natural materials. By that I mean wood, bamboo, backed, multi-lam, etc. I just recently made my first couple of glass bows which caused me to want to know more about them. One thing I am curious about. I initially was under the impression that the reason for multiple laminations in bows was to allow the pieces to bend in the form under pressure without breaking, but as I looked at the Hill style longbows there isn't really that much of a bend other than the handle fade. Why wouldn't you use a single piece of wood between the glass rather than multiple ones? Would a single one take more set? Would it be weaker? Just curious..

[Ice Mike]

I'm no expert by any means, but my understanding is that there are a few reasons for the multiple lams.

For one, with multiple thin lams it is easier and more predictable to calculate a final draw weight. Second, with all of the "character"  wood used in glass bows, multiple lams help reinforce the weak areas from one peice to the other.  Third, yes, a single thicker lam would be more likely to take a set. One more I think would be that you couldn't make a decent bend up the fade curve without damaging the lam if it is too thick.

Again, this is just the way I understand and that does not in any way make it an end all answer.

[Bowjunkie]

Multiple lams of thinner wood are easier to bend in forms and around shapely risers than a single thick piece. They may help a tiny, tiny bit in taking less set, but a few more important reasons are... multi-lam bows are less likely to fail because of an issue in the wood. An issue like a knot, cluster of pin knots, growth ring runout, grain runout, and others can mean the death of a bow made from a single piece, whereas in a multi-lam bow, the effects of a defect in one lam can be virtually negated by virtuous wood around it.

Using multiple lams in a bow also helps to distribute stress more evenly... stress at the fades and wedges and such. I have seen single-wood lam bows, sandwhiched between glass fail in such places where I feel surely that multiple lams there would have been their saving grace.