can'tlose the porpise!

[Coach]

I've made more than a few wood bows but I have had a new experience with this one! 62" ntn and 32#bamboo backed Ipe.  Eighth inch positive tiller and tiller looks good. String alignment right on.Have changed the nock point from straight to half inch in small increments.  Have shot 1716's 1816's, 2016's (know they are way too heavy), etc..  1716's porpoise like crazy.  Have gone the full gamet on brace heights as well.  Feel it must be a timing issue.  Bow shot well so I already put the finish on and then this has happened.  New one to me.  My plan is to scrape top limb down to quarter inch positive tiller and see if this helps.  If it solves the problem I can then pike it and get weight as I have plenty of length for my daughters draw. Oh, and the bottom limb is a half inch shorter..  Any thought from anyone on what the problem could be and do you think my plan is right?  Coach

[Bowjunkie]

Working the top limb down on a guess? What if it's the bottom limb that needs worked? You'll be WAY behind then.

Your troubles are exactly why I tiller the way I do.... with no preconcieved brace height measurements as my goal. I time the limbs and it is what it is. Today I tillered a bamboo backed yew/osage tri-lam bow with a shorter bottom limb, for split finger and once the limbs were syncronized, the tiller measurements were dead nuts even.

[JamesV]

I build mostly glass bows now but I have built  a number of IPE/bamboo bows and always cut both limbs the same length. Never had the problem you are describing but I think it is as you said a timing problem. You should get an exact answer from the wood bow guys here, they know everything about tillering wood bows.

James

[Coach]

I built three of these bows ant the same time and they are all identical except the draw weight varies within a five pound range.  This bow is the only one with this problem.   It is the lightest of the bows and has the least positive tiller.  I know there are lots of ways to get a job done, but am going to have to start somewhere to fix this timing problem.  Appreciate comments as this is how I continue to learn.

[Coach]

I built three of these bows ant the same time and they are all identical except the draw weight varies within a five pound range.  This bow is the only one with this problem.   It is the lightest of the bows and has the least positive tiller.  I know there are lots of ways to get a job done, but am going to have to start somewhere to fix this timing problem.  Appreciate comments as this is how I continue to learn.

[J.F. Miller]

a picture would help.

I'd be willing to bet that your bottom limb is too stiff. I'd suggest raising your nock point as high over 1/2" as is necessary to get your arrows to fly properly, but I suspect that somewhere around 5/8" above, your arrows will be flying better. I'd try this first, before you go working on upper limb.

forget what you think is correct about having positive tiller in the upper limb of every bow you make and tiller for proper balance and timing, as Bowjunkie suggests. let the wood and the design tell you how it is supposed to be tillered.

[Pat B]

Sounds more like an arrow problem. If your braced tiller looks good, your full draw tiller looks good your bow will shoot well if you are useing appropriately spined arrows. All the bow does it propel the arrow. If you get bad arrow flight, try different arrows. I don't shoot aluminum so I can't talk to that. Try cane arrows or wood arrows that are 3 or more inches onger than your draw.

[Al Dean]

Try double nock before cutting anything.  May not help but arrow slipping on string can cause this issue.  Besides it cost nothing and takes no time.