Author Topic: Pyramid bow, tillering the taper?  (Read 3153 times)

0 Members and 1 Guest are viewing this topic.

Offline Geofbow

  • Member
  • Posts: 7
  • Lifetime traditional and primitive archer/hunter.
Pyramid bow, tillering the taper?
« on: August 24, 2010, 12:24:13 am »
This is a continuation of my first Pyramid bow, hickory backed hickory board, Ive been tillering the thickness  to this point to get some of the meat off.  and it's looking pretty good at the 20 inch draw, and still  60# and returning to its slightly reflexed position when unstrung.  My Question and confusion is about tillering the front view profile.  Do I simply shave off the sides of the taper to reduce draw weight or am I expected to adjust the arc of the tiller by shaving off wood on the sides of the areas that are not bending enough.
  My taper runs 2 3/8ths at the fades to 3/8ths at the nocks and the thickness is about 1/2 inch except the last 8 inches of tip.  Will someone give me a blow by blow, or can you point me to a site for the process for the pyramid challenged               
                                                                  Thanks  Geof

Offline 4est Trekker

  • Member
  • Posts: 311
Re: Pyramid bow, tillering the taper?
« Reply #1 on: August 24, 2010, 12:52:42 am »
I've built a gob of pyramid bows and I tillered and reduced weight on most of them by thinning the belly (within reason). Once in awhile I would would removed wood from the side to reduce weight or adjust tiller, especially if the bow was particularly wide or the limbs were getting too thin to continue removed wood from the belly.  Some swear by the rule that you reduce weight by taking wood off the sides and adjust tiller by taking wood off the belly.  I agree, but it's not the only way.  Either way, taking wood off the belly is the quicker (and often more dangerous!) way of getting both done, but you can get carried away in a hurry. Remember the rule that if you double the width of a limb, you double it's strength.  If you double the thickness of a limb, you increase it's strength eight fold. 

Now, for a basic tillering review:  You worry about the tiller first, never drawing past 1) perfect tiller, 2) your intended draw weight, and 3) your intended draw length, in that order.  If you're pulling it 60# @20" but don't have perfect tiller, you're causing undue set.  In your case, I would take wood from the belly, assuming your limb tapers are spot-on and don't draw it past where the tiller is true.  Remember to exercise the limbs between each wood removal.

Post pictures, have fun, and be patient!  ;)
« Last Edit: August 24, 2010, 12:56:49 am by 4est Trekker »
"Walk softly, and carry a bent stick."

"And whatever you do, whether in word or deed, do it all in the name of the Lord Jesus Christ, giving thanks to God the Father through him."  Col. 3:17