R/D Tiller Help

[BCWV]

I made a second run at a BBO. This one's holding so far. It looks to me that the bottom limb needs a little work right out of the fade but on my tillering tree, my gizmo says it's good all the way around. I went with Dean Torges dimensions and the bottom limb is 1 1/2 shorter than the top. It shoots sweet and is the smoothest bow I've made so far the way she sets now. 1/8 positive right now.

 What do you fellas think it needs.

 

 Thanks

 Brad

[Echatham]

I can't see anything wrong with that.... maybe a more experienced eye can...

[BCWV]

Thanks Eric, the more I look at it the more confused I get! I stopped on it this evening and my daughter and I took momma out for an early mothers day dinner. I thought I'd post the picture and get some more eyes on it. It may be the shorter bottom limb making it look different to me.

[Echatham]

makes sense to me

[takefive]

Looks great to me    

[red hill]

Looks good from here, too!

[jsweka]

Looks good to me too.
Limbs of different length would just mess my head up.

[BCWV]

Thanks fellas. I'll shoot it in and post some pictures when I get it finished.

[J.F. Miller]

both limbs look a bit stiff in the outer most 12". not much, but I like to see a little more movement in that area than you have. how long is bow ntn? where did you measure the tiller to determine it is 1/8" positive? I'm assuming you mean the upper limb is bending 1/8" more than the lower. for D/R bbo's around 64" with lower limb 1 1/2" - 2" shorter I usually wind up with even tiller or very close to it. sometimes I have slight positive tiller in lower limb, sometimes positive in upper, but I don't really care about the measurements as my destination for correct tiller. make yourself a tillering tree with a single point of contact on the handle and tiller for balance, not to a predetermined measurement. let the design, the wood, and your hand pressure/placement on your grip guide you to final tiller. the lengths of the limbs does not matter (Yumi style bows are extreme example) if you tiller for balance.

I made bows with the lower limb too stiff for 15 years because I didn't know any better. yes, they shot ok, but a few years ago I started tillering for balance, and instantly made noticeably better shooting bows. tillering to a predetermined measurement will seldom, if ever, result in optimal tiller.

[Art B]

I think it's always best to tiller for even limb strain at full draw. Looking at your method of drawing and the way you're gripping your bow I'd expect you would wind up with 1/8" positive tiller anyways.

So, how's the limbs feel at full draw? Strain on each limb feel the same? If so, then do nothing and shoot your bow in. Check for tiller changes often using a ruler. But if you have even limb strain now, then I would expect things to stay the same over time.

Using a split-finger draw, the greatest limb strain will be right at the lower fade. I generally leave that area alone and move further out to even up tiller, if necessary........Art

[Roy from Pa]

I think it looks very nice. Like Art said, the lower fade area will get a workout, so after many shots it may come around a little. But I would  stain her and seal her and call her done. And your Apron is so sexy. Dye it pink and you will be all set... LMAO:)

[John Scifres]

Why did you make your riser so long?

[Bowjunkie]

J.F.  Miller, you sir are a man after my own heart. Your view on tiller, timing, and predetermined brace heights mirror my own. My bows too took a leap forward when I began to better wrap my head around the bowmaking why's and what for's and then began using syncronization of the limbs as my compass, which coincidentally also makes bows more user friendly, arrow friendly, predictable, tunable, stable, etc... all the sorts of things bowyers and archers claim to value.

As far as BCWV's bow pictured above. I too wondered why the handle section was so long, and while it looks flat to me as well in the outer limb, without an unbraced profile to compare it to, I'd be hesitant to advocate trying to attain a perfect circular arc. If considerable reflex is glued into the outer limb, in order for the whole limb to do equal work, you'd WANT it a little 'stiffer-looking' there, IMO. In other words, just because it 'looks' stiffer, doesn't mean it's 'acting' stiffer.

Without the unbraced profile as a starting point reference, we can only guess what it should look like at full draw.... for all we know, the outer limbs may already be working more than elsewhere..


Now, I gotta go dig a piece of osage out of my eye  

[BCWV]

Thanks fellas.

 The bow is 64'' T to T, 62 N to N. Yes, the upper limb measurement is 1/8 more than the bottom. The bow shoots very well and both limbs seem to be pulling even.

 As for the handle length, I can say I have no idea why I had it that long. I used the piece of osage from my last try and after grinding my broken boo off and I was a little thin in the middle. I glued an 18" long piece slat in when I did my handle glue up to give me a little more to work with. I guess I just got a case of the dumb butt and ended up with too much handle. I've worked it down and now have a 9" handle on it.

 I have a coat of stain drying on it now but plan to shoot it more before putting finish on it. I'll post an unstrung pic when it dries.

 I'll see if I can find a pink apron Roy, my mom should be able to help me out there. Do you need one? May be able to hook you up.

[J.F. Miller]

Bowjunkie, my friends call me Jamie.   :D  

Brad, are you measuring your tiller at brace height or at full draw (or nearly so)?  just outside the fades at deepest measurement, a foot from the nocks or both? lots of questions, perhaps all irrelevant if you are satisfied with results.

to what length is bow drawn in picture?

[BCWV]

Jamie,
 I'm measuring at brace height, just outside the fades at deepest measurement. Didn't have a clue there was any other way to measure it!    :D   and I'm drawing 26".

 It seems that some think I'm tillering with a predetermined positive measurement goal but I'm not. I'm green as grass to bow building and am trying to just get her bending as even as I can. I just posted the measurement as information along with the limb length.

 I shot it quite a bit today and am very happy with how the bow performs but I've learned on each bow and always want the next one to be better.

 Brad

[J.F. Miller]

what the bow looks like at brace height is practically meaningless. the tiller measurement and bending profile at full draw or therabouts is what matters. your bow is bending gracefully and looks good. if it shoots to suit you, then it's time for some finish.

[BCWV]

Thanks Jamie.

[John Scifres]

A long handle isn't necessarily a bad thing.  It can make for a snappy bow with more work being done closer to the tips, minimizing the amount of mass being moved.  It does this while allowing a lower string angle than a similarly made limb with a shorter handle.  Jim Hamm talks about this in TBB 1 I think.

I agree with Jamie, if the bow makes you happy, finish it and shoot it like you love it.