Length and draw weight?

[monterey]

This should be pretty simple and I have a pretty good idea of the answer..... but, there the blank sits on my bench needing a bit of shortening to hit the desired raw weight.  So, I defer to the learned opinions of this board;

typical 68 inch long bow with a bit of limb set back.  eighteen inch riser.  My calcs say it well be a 43.4# draw at 28".  I want it to hit around 48#.  How much should I shorten the NTN to shed that 5# + or -?

[Pat B]

Cut temporary nocks 1" below the existing ones and weigh it. If not enough weight cut two more temporary nocks 1/2" below the last two and weigh it again. Exercise the limbs well after each change. When you get to the weight you want reshape the tips and finish. By shortening the limbs you will be adding more stress to the limbs so take it slow and easy.

[monterey]

Pat B, going out to the shop to do just that right now.  Be back in a few minutes.

Thanks.

[monterey]

Ok, did nocks at 70" for starters.  This bow goes to a guy who draws to 31".  Here's what I got with nocks at 70:

28"---------42#
29"---------44#
30"---------46"
31"---------49#
32"---------52#

Close as I can get with the bathroom scale.

I want this bow to land around 53 to 56 at the 30 to 31 inch draw length.  At this point I'm thinking to go straight to a 68" NTN.  What do you all think?

[Pat B]

With temporary nocks 1" below the original nocks will be the same as a 68" bow(n/n). If that gets you what you want, make the nocks permanent and reshape the tip. If not go 1/2" less and see. It is easier to cut temperary nocks than to reshape the tips each try.

[monterey]

Pat, advice well given and taken.

At 68" NTN I was so close to the desired end that I decided to stay right there and made the 68" permanent.  FD curve ended up like this;

 

Thanks for your suggestions.