I figure I should give a little update. As with most new designs, I ran into quite a few problems along the way, learned a few things that I'll do differently on the next one, and spotted a few places for improvement.
These limbs were originally designed to make a 58" bow on the 14" riser. I filed in shallow string grooves at 60.5" before final profiling to see how the limbs were bending. I screwed up when I marked my tree, and forgot to add the 1 3/4" from the throat of the grip.
So when I thought I was at 28", I was in fact at 29 3/4". I ended up only taking the bow down to 59" instead of the planned 58". Naturally, this threw my draw length and weight readings. It was originally intended to have a 1/2" longer top limb, but I didn't care for the profile so I made it symmetrical.
I like the braced profile now, but it threw me a curve ball with the tillering. While the riser was in block form, the limbs wanted a neutral tiller for level nock travel at my designed nock height. After shaping the riser, and final prepping of the limbs, I ended up with 1/16" positive tiller. I thought this would be close enough to shoot and make final adjustments later.
I sprayed some thunderbird high solids sealer on the riser, and spent some time shooting her with the longer string. I settled on 6 3/4" brace and found some arrows that flew true. I ended up re-working the grip a touch, and concluded that the tiller still needed some adjustment. That's where I'm at now.
Only problem is, I'm not sure which limb needs to be worked on. Conventional knowledge would dictate weakening the upper limb and increasing positive tiller. My past bows have all shot best between an 1/8-3/16" positive. But they have also been slightly asymmetrical. I put the bow back on the tree, and it says the bottom limb is too stiff (cable drifts toward the bottom limb). Here's the weird thing; when I nocked the arrow at 3/4", the bow smoothed out a bit and was quieter. But after seeing the results on the tree, I lowered the nock to 5/16" and the bow shot the best it has! Only problem is that nock height is too low compared to the shelf to get clean arrow flight. 5/16" was definitely better than 3/4"! It seems that 1/2" has the limbs too far off time to shoot smoothly, but the nock height is just about right for proper arrow flight.
Has anyone else had a similar situation? If so, what was the proper fix? More or less positive tiller? It's my thinking that less, or a weaker bottom limb, will shift that balance point and like wise the nock point up a tad. I'm hoping that will bring the limbs into better timing with a high enough nock point for clean arrow flight.
I really can't afford to go the wrong direction here, as my limb profiles are just about as narrow at I want to take them, and I'm already at the bottom end of my desired draw weight. I do have room to pike the tips, but I'd prefer not to as the overlays and shaping is already complete. Any and all advice is welcome. Sorry for the long post, but thanks for any insight.
Topic: My latest hybrid 3pc (update) (Read 1059 times)
