early vs. late growth on bellies

[jeffp51]

I have been tillering a bow today, and I was wondering if anyone has noticed a difference when the belly is mostly on a early growth ring vs. when the belly is predominantly late growth.  It felt like the draw weight would drop in fits and starts, and I wondered if there was a correlation to the rings on the belly. This is with osage.

[bradsmith2010]

I have not noticed that

[Eric Krewson]

I have noticed that some bows slide gracefully into tiller, others do it in jumps and starts. I always hated the ones that you could scrape and scrape on the limbs and nothing would happen, then BANG, everything would change. I never looked for a reason, just chalked it up to wood being wood.

[SLIMBOB]

Never been a concern.  Erik's point is on the money.

[Pat B]

I doubt that early wood on the belly has any affect on the tiller or tillering of a bow. There just isn't enough substance to it to have an affect.  Like Eric I have had bows that don't come to tiller easily but I doubt the early ring has anything to do with it.

[George Tsoukalas]

Could be but i never noticed it.  Jawge

[Jim Davis]

The early wood is obviously much softer in ring-porous woods such as Osage and locust. That is readily apparent to anyone who has chased a ring.

This is one of the reasons I like making bows that taper mostly in width and are mostly uniform in thickness--"pyramid" bows.

Bows that taper in thickness have several growth rings on the belly that taper out to early wood and then end.  Since compression (and tension) forces are concentrated at and near the surface of a bending limb, those early-wood transitions create areas that are weaker.

That's one reason there is value in using wood that has a high ratio of late wood to early wood

This variation in strength is moderated by the fact that the early-wood transition does not happen in a band straight across the belly. The ring's cross section being an arc, it makes a long elliptical transition, spreading the effect over several inches.

So in practice, the early wood usually makes no noticeable difference.

[bradsmith2010]

sometimes leaving a bow strung a few hours each time,, will help it settle in,, or equalize during tiller

[jeffp51]

I have noticed that some bows slide gracefully into tiller, others do it in jumps and starts. I always hated the ones that you could scrape and scrape on the limbs and nothing would happen, then BANG, everything would change. I never looked for a reason, just chalked it up to wood being wood.

This is exactly what this one has done--which is funny, because its sister stave from the same piece of wood was really smooth and predictable about the way it tillered--also good because that one was one I used to teach a neighbor kid, and this one has a little more character and is meant for my son.  pretty wood.