Knotted string

[Jim Davis]

Asharrow,
                  He mentioned a string, a bow stringer and a tillering string, so we are all on topic sir...
                                                                                                                                                  Don

Right you are. I guess it seemed to me that he wanted most to know if his stringer was safe to use.

[Onebowonder]

Isn't a bow under the most stress while at brace?

NO, I'm pretty certain that there is considerably greater stress on a bow while at FULL DRAW.

OneBow

[PEARL DRUMS]

The string is under the most stress at brace while the limbs are at the most stress at full draw.

[Onebowonder]

The string is under the most stress at brace while the limbs are at the most stress at full draw.

 

HELP!  I don't get the physics of that idea.  A bow's limbs and the string attaching them seem like a closed system to me.  If there is increased stress on the limbs, that stress has to be equivalent on the high tension string connecting them.  ...am I missing something fundamental here?  ...are you being funny maybe and I'm too dull to get the joke?  I'm getting more coffee!

OneBow

[DC]

I don't understand it clearly but I have measured it. On a 40# bow the string is under about 43# at brace and then drops off steadily to 40# at full draw. It's really bizarre to watch the scale drop as you draw the bow. The lower the brace height the higher the string tension is. At least until the scale ran into the bow, that's when I stopped.

[JoJoDapyro]

The string is under the most stress at brace while the limbs are at the most stress at full draw.

That is what I meant. 

[joachimM]

HELP!  I don't get the physics of that idea.

OneBow

Smartphones are not ideal to explain this, but IMO it comes down to string^tip angle increasing during the draw, and the resultant force on the string decreasing because of that. When a string breaks, it happens at the end of the return to draw when an arrow has been shot, most of the time.