Recurve shape when strung

[DCM]

Absolutely.  But I'm not sure you and I really ever got closure on just which limb is already getting a free ride in the conventional config.  I have tried to argue the lower, but you'd have to concede the questions of a) stess on the upper and b) longer lower string segment versus upper.

If you do, and if the lower limb enjoys a better string angle, the upper is under more strain (being both shortened and weakened), then why not stack a few more potaters on the lower limb's wagon?  Yes it would add stress, but it would also help balance the stress, given the aforementioned.

Admittedly, in glass bowyery there are practical constraints, how much riser one has below center for limb attachment and handle, which might well outweight the potential benefits, which are very small since with glass we have gobs of extra capacity in the material we don't really tax.  But I think the theory is sound, and WELL practiced in antiquity (English longbow for example, not the yard bows of the 18th and 19th century, the war bows of the 14th and 15th).  In wooden bowyery to be honest the benefits are not so pronounced as to be compelling.  But in cases where one is treading the edge of calamity, I've convinced myself allowing the upper to have parity with the lower works in ones favor.  I would argue, have argued, having the arrow pass, but more importantly the nock point, be at dimensional center is the more balanced config, one where the lower is not shorter, but even with the upper.  And in all other aspects, of tuning and shooting manners, I think there's either no difference or the nod goes to this config (arrow pass at center) as well.  Very accomplished bowyers (Eric Krewson you would know of for example, but others like JD Jones) will disagree, but I have not heard them make a compelling argument other than.... hearsay and antectdote.  LOL

[Orion]

DCM:  The fulcrum/arrow shelf is above center so the bow hand applies most of the pressure/force on the dimensional center of the bow.  That's why high wrist grips are located closer to center of the bow and low wrist grips further above center.

I haven't recorded the tillers on the bows I've measured to date, but if recollection serves, they were all pretty similar, about 1/8 - 3/16 positive tiller in the top limbs.  Also, I shoot all of them with the nock point at the same height, about 9/16 above the shelf, except for the Morrisons, which require me tomove the point up about 1/16 to 1/8 inch more.

Dan:  I believe you're right.  A grip that places the palm of the hand directly over the center of the bow (i.e., an arrow shelf cut 2 inches above center) would tend to flex both limbs equally, while a grip that is located closer to center (shelf 1 1/4 above center) would place more of the hand below the center of the bow (unless it is shot with very high wrist), which would seem to stress the lower limb more by bending it more in relation to the top limb.  The hand placement in effect shortens the lower limb vis-a-vis the top limb.  Thus, the negative tiller of the lower limb, (or the positive tiller in the top limb) is a way to equal out the bend in both limbs at full draw.  Am I making any sense?

[Orion]

Just checked a few tillers.  My Robertsons, with arrow shelfs about 1 5/8 to 1 3/4 above center, have modest positive tiller in the upper limb, about 1/8 inch.  So do the Hills, with shelfs about 1 1/4 above center.  My Dwyers, on the other hand, with shelfs 2 inches above center, have no difference in tiller between the upper and lower limbs.  Supports what I just said.  Could be a fluke, but got to assume these guys know what they're doing.

Whittler:  We sort of hijacked your post.  Sorry.  To state what I said earlier.  Your bow design is normal.

[DCM]

Whittler got his answer in the first reply.  I understood what he posted to be, 1" of negative tiller.  I'd go to the bowyer for that question, for sure.  Although hickstik made a good point as well.

Boy, that part about "with shelfs 2 inches above center, have no difference in tiller between the upper and lower" sure puts a kink in my step.  Honestly, the more I investigate this topic, the harder it gets to understand.

Notwithstanding the stuff about where we put our bow hand, conceding we want it as close to the fulcrum as practical, I still think where we put our string hand matters, actually the arrow nock, as much or more.  The dang bow is gonna balance itself in your hand regardless of what we do (by rotation) when we draw, and grasping the string increasingly higher, towards the upper string groove, can't help that balance.  At least that's what I think.  And when we loose, the string is what's driving the bus.  And let's face it, what's really important is what happens to the arrow when we loose.  Every choice we make is about getting the arrow to come off clean, converting as much energy from the bow as we can manage.  Hard for me to imagine how having the arrow leave the string from 4" above center helps in any way.

For a "simple stick and string" this stuff can get freaking complicated.  LOL

[kennym]

Keep goin fellows,this is very interesting!!
       

[Orion]

DCM:  I agree where the arrow shelf is not only determines where one's bowhand is in relation to the center of the bow, it also affects where the drawing hand/fingers are in relation to the center of the bow.  And different positions are going to put different levels of stress on the top and bottom limbs.  Of course, the shape of the riser, the length of the fadeouts, whether they're symmetricaal or not also play a part.  This is about as far as I care to take it.  My head hurts (L0L)  Good luck.