shelf point of contact

[RySanpei]

What is the reason for the shelf point of contact to be inline with the narrowest part of the grip? I've been told a few reasons, but when I tried to move the point of contact I couldn't see the affect on arrow flight.

[Charlie Lamb]

Part of the archers paradox is that the bow rotates on an axis and that axis is at the low point of the grip.

In theory this is the most forgiving spot for arrow contact.

This isn't always a hard and fast rule because of design variations, but is a great rule of thumb.

In days gone by, when I was a much younger man, it was suggested that in tuning the bow to the arrow (we most often tune the arrow to the bow these days) the spine of the arrow could be effectively "softened" by moving the rest or arrow plate toward the arrow's point from the pivot.
To stiffen the spine of the arrow one would move the rest or arrow plate toward the feathered end of the arrow.

[RySanpei]

Thank you Charlie.
I have this custom bow that has two different contact points for the shelf and the strike plate. The contact point on the strike plate is inline with the throat of the grip which would work with the concept of the axis and arrow paradox, but the contact point on the shelf is closer to the back of the bow.  So in theory as long as the strike plate contact point is inline and there is minimal contact on the shelf, I would not need to build up my shelf in order for it to be inline also?  Sorry if this sounds confusing.

[ChuckC]

What Charlie said.  I think...to say it so I can understand it, if you have a point of contact anywhere but imediately above the deepest part of the grip, or, the contact or pivot point for your hand, any change in grip or holding the bow CAN move the arrow a bit out of line and cause a change in contact point (twist the bow a bit and see what I mean).  Works both for up and down and sideways twist if you count the pivot points on the shelf and the riser.
ChuckC

[Charlie Lamb]

Ryan... you should be fine.  I've never found it to be real critical.

Chuck... thanks. You cleared it up quite well. I was struggling a little to explain what I knew.   :D  

And just for the sake of clarity... there are two types of archer's paradox. One is the gyrations the arrow goes through as it passes the bow and the second is how the bow moves in reaction to the archers release and bow grip.

Both are definable and important to the proper delivery of the shot.

[ChuckC]

Aw Charlie...you know that stuff way better than I do.   You just have to speak slowly and use small words so then I can understand them too !

Oh, and pictures help me also !  

ChuckC
 

[RySanpei]

Thanks guys!
Ryan

[Richard in OK]

OK -- so here's a question. On every photo I see of a bow, and on my own longbow, the high point of the shelf is forward (toward the point) of the deepest part of the grip. Why?

[ChuckC]

Don't know.  but not all.  If I make it it is not.
Pretty certain at least SOME others as well.

If the maker draws an arc as the template for the shelf, the center, or high point of the arc is in the middle, front to back.  If they do not offset the arc at all, they, you, will end up with a shape as you described.

As Charlie stated, it probably doesn't mean as much in real life as it does in theory.

ChuckC