Wednesday, June 9, 2010


I like to tinker with archery equipment.  I got my first bow before I turned 10 - a Bear Blue Denim compound (I still have it).  I still remember my dad and brother trying to change the draw length for me out in the front yard.  Dad forced the limbs together while Ricky moved the cable ends to holes drilled in the eccentric brackets bolted to the ends of the limbs.  It came from Target in South Bend.  I shot it so much that dad realized I was serious. 

When it became obvious that I'd outgrown the Blue Denim, dad consulted with a cousin, Billy Joe Risner, who had his own basement pro shop, and was notorious for trying out the latest-and-greatest bow gear.  He directed dad in purchasing my first REAL bow, a Martin Cougar Magnum.  That Martin still ranks as one of the top 5 gifts of my life, and I still have it.  The craftmanship is exquisite, and every year I toy with the idea of setting it up and killing another deer with it.

Anyway, I've been hooked on archery since I was a little boy, and my affliction doesn't seem to improve.  I recently bought a new bow press that handles the modern parallel limb bows, and this week built a prototype draw board to help look at cam timing, cam lean issues, nock travel, draw force curve dynamics, and much more.  I'll eventually have my brother help me build a metal (welded) frame instead of the wood variety I'm experimenting with, but the fun is in refinement!

As an example, I put my Hoyt ProTec on the draw board last night, and used the draw lenght/weight data to build this draw force curve table:

It shows the bow has a pretty gradual build to peak, a wide peak top, and a fairly gradual shift down to the wall.  This curve doesn't show it, but the bow has a very narrow valley at full draw.  Taking peak draw weight (44 pounds) and subtracting holding weight (16 pounds) gives the let-off amount of 28 pounds.  Dividing 28 by 44 and multiplying by 100 gives the percent let-off of 63.6%.

I'll compare these numbers with those of my new Maxxis when I get a chance.  Note that I've shortened the ProTec up as much as the cam modules and cable/string twisting will allow, and backed the limb bolts out as far as possible.  I'm setting the bow up for a beginning adult archer that needs low draw length and weight.

No comments:

Post a Comment