Do you guys use belly rings as a rough guide when tillering? Or are they're just too many other variables to make it worthwhile.
Belly rings are an excellent guide IMO. I use 'em in conjunction with any applied taper...........Art
Nope. I pay very little attention to them. Too many variables. I gauge my thickness, tapering, tiller by other more reliable means.
I don't use belly rings either. I scrape wood until both limbs bend evenly and together. I don't think I've ever built a bow where the belly rings were centered or evenly spaced well enough to depend on them for tillering.
Way back when, I watched the Glenn St Charles yew bow making tape where is stressed feathering the grain on the belly of his bows nice and even.
I tried to make a few osage bows with the same feathered grains and the results were awful, horrendous tiller.
If you had a perfectly even grained piece of wood you could use your belly grains for a rough tillering guide. For the rough, twisty stuff I make bows out of it would be impossible.
I don't use growth rings for anything other than a secondary or tertiary reference when tillering. it has been my experience when you can manage to center the crown of your staves back correctly and follow any side to side undulations on the grain correctly, (both of which you should always strive to do, imo) growth rings will feather out down the middle of the limbs by default.
from the other direction, if growth rings don't feather out pretty much down the center of a bows limbs, you didn't align the crown on the back properly or didn't follow the grain. both of these things are considerations that need to be addressed when laying out the bow, not when you get to the tillering phase. by then, it's too late. while it isn't always possible(for a variety of reasons) to nail the crown and follow the grain religiously, it can be done satisfactorily most of the time.
I use them as a guideline during the beginning stages of tillering. I dont pay as much attention to them later on in the tillering except for up around the fades.
I agree with Mr. Miller. I have found that most of the time things work out that way unless a know or other defect is present in the stave. Imo they are excellent guidelines and teach my apprentices that way. However, they are not the end all answer and that needs to be considered like stated above.
Thanks guys, thats about what i thought the answer would be.
I use them religously. Most of my bows come off the vice and get braced with little extra tiller work.
Well it hain't no wonder all your bows come out all screwed up then Pearly Boy :laughing:
Now you know!
The reason that i began to think about this is that I am working on an osage pyramid bow, so theoretically the belly should all be in one ring. well it just so happens that after roughing it out and cleaning it up both limbs were in the same belly ring but one was waayyy stiffer than the other. i think the culprit is a section of the bow where one limb is concave on the back of the bow, making it structurally much stiffer.
Double check your width measurements. Mark every 3" along both limbs. Number each mark from the handle to the tips on each limb. Use a caliper and make sure the #1 mark from the upper limb matches the #1 mark from the lower limb. I am always shocked how far off I can get when I don't take this extra step.
Osage can get screwy in its growth rings especially from limb to limb. But my most carefully laid out, best tillered bows do follow the belly rings really well. Good luck. Take pics. Post 'em.
The butt end rings are probably thicker so that would make a difference.
I pay attention to them when I am roughing out the bow as a general guide. Once to tillering, really don't pay much attention then.
should'nt the very end of the growth rings stay in the center of the limb when scraping and tillering. thus keeping limb thickness the same from one side off the limb to the other. in the tbb vol 2 i think they referred to these as rifts. keeping the rifts down the middle of the limb but not always evenly spaced???