If I build a bow with a 21 degree angle for the limb pads and when I am through with it the poundage comes out to be 50#s @ 28" will the poundage be affected if I build an exact copy of the riser but now the angle is 17 degrees using the same limbs? If there is a change can you explain why?
Yes it will change. It will increase draw weight if you go to 17 degrees. Probably about 5-15 pounds
I built a T/D 10 years ago and wanted to increase the weight without building another set of limbs. I used 22 degrees on my riser limb pads. I took off an additional 1/4" on the limb pads on the end with the bolt this flattened the angle. Somebody that is good in geometry can refigure the angle. I have to get to work. The pad was 4.5" long. Long story short I only gained a pound! It wasn't worth the work! This was my experience.
It will put more preload on the limb and increase the weight some.How much will depend on the stress already on the limbs at brace and how smooth the limbs pull at the end of the draw.An ilf riser works the same way to increase weight and change tiller but normally will only be about a 5lb range on limbs around tha weight.The easiest way to see before hand is to shim the limbs on your riser to that angle and weight the bow.Be carefull to make sure the limbs won't move and don't shoot it unless you have some kind of solid setup. jmo