tiller question...

[DCM]

Frank if my understanding is sound, shortening the lower is the same in effect as making it stiffer.  I am NOT saying shorteing it makes it stiffer, which while true is irrelevant.  Rather that by making it shorter one balances it's inherent disparity with the upper, making positive tiller (used to offset this) less necessary.  Seems to me we'd want our bows to shoot well with as little nock height and positive tiller as practical.  These are by definition measures of asymetry after all.  In the glass bow game it is largely irrelevant as there we don't have to worry about being so close to the edge of the elastic potential of the materials.  Perhaps this accounts for our apparent fascination with what is labelled "even" but is in fact "shorter upper" limbed bows.

[medicinewheel]

lennie! - many thanx: i had problems to understand what DCM wrote in the first segment, now i get it. and i guess it's exactly what the problem here is! longer limb PLUS 1/4" makes to much bend.
i'll retiller the lower limb a bit, doesn't matter if i loose another 3 or 4 pounds; it's a lady's bow and it's still a bit to strong for her with 38#@26".

again, thanks a lot

[medicinewheel]

david! - thank you for your comment; i certainly understand better what's going on now!!! a lot of problems i had with tillering probably came from the same source: to much positive tiller.
i'll keep you posted on the corrections of the bow!
frank

[medicinewheel]

okay, took the tiller difference down a little; it's a bit more then 1/16" now and i'd say that helped it some.
what do you think??


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[DCM]

Frank,

We were having a rhetorical discussion about tiller, on the thread where you posted your bow.  My first comments on this thread about your bow haven't changed.  I would judge whether 1/16" or 1/4" tiller is "enough" based upon how it shoots, to some extent how it looks drawn by hand and how it takes set from work.  For example, is it shocky, loud, take a lot of nock height for good flight, does it set equally along the entire lenght of both limbs?  Again, I think it looks great, but thought was fine before you softened the lower limb as well, notwithstanding the aforementioned, which is the only way to really know.

[Justin Snyder]

Frank, I believe David is right. The 1/4" positive tiller is to compensate for a bow having even limb length.  I would still shoot it and decide from that, but 1/16" is probably better. 

Perhaps this accounts for our apparent fascination with what is labelled "even" but is in fact "shorter upper" limbed bows.

The limbs are the same length on my bows. It is in the riser/handle that there is some question.  The bow certainly is not symmetrical though since the arrow passes above center and adjustments are made to compensate.  Justin

[DCM]

It is important to realize this whole discussion revolves around the 0" to 2" between the dimensional center and the arrow pass on our bows.  In fact, I think relatively few people put their arrow pass at even 2" above (on a typical 2/4/2" "handle"), 1 1/2" being the more common.  I guess my point in advocating this position, which seems to be my lot in the craft lately, is that placement of the arrow pass is a decision we make when crafting our bows just like every other one.  How wide, how long, where the bend starts, what finish, etc, these are all decisions we make, one would hope with forethought and purpose.  Just because some of us accept without question the decision to always go 1 1/2" above doesn't mean the choice doesn't have implications, and that someone else actually made the decision for us.  I just don't understand why, if there is a benefit which is my belief, folks don't at least entertain the idea we have this option, while at the same time chasing nearly every other option with vigor and wonder. 

[Marc St Louis]

Frank

When it comes to full draw I go by feel rather than how it looks. If the bow feels good when you draw it and does not pivot in the hand then that is good, this of course as long as the limbs have no hinges and bend smoothly.

[Ryano]

Frank, it looks very well tillered, I just cant get my self used to the looks of a shorter lower limb. I've made a few bows that and I see no advantage to it. For me its more of a looks thing. I do the same as Marc, shoot the bow first before finding the sweet spot where the arrow should pass.

[Ryano]

Frank, check out the pictures when Sarah gets around to posting them of the bow I gave her on the christmas exchange. It has a shorter lower limb.

[Justin Snyder]

How wide, how long, where the bend starts, what finish, etc, these are all decisions we make, one would hope with forethought and purpose. 

Cant argue with that. 
A 1/4" difference can be huge so I recomend shooting it before making any final decisions.  Justin

[medicinewheel]

gentlemen!  -  i'm so sorry for the late reply; i have been through the busiest week in a long time!

david, i understand what you mean and i'm glad about the information contained! well the bow looked strange and felt a little unbalanced, too. but i couldn't really shoot the bow to find out, since it's to short drawlenght and to low poundage for me. the lady i made it for was pleased with it, but she is not experienced enough to tell me how balanced or not it felt when she shot it.
with the little adjustment i made in the tiller it now both looks and feels better to me!
i had similar problems before, so now i know what these problems originated from!

thanks to all for - again - helping me through a problem; i've said it before and i'll probably say it again in the future: this is the right place to ask when one has a problem in bowmaking!

well, the bow is one maple-backed purple heart and i managed to finish the bow with no frets or cryssals on the belly. today i found some time to finally sand it and do some build up of the handle! leather handlewrap and finish to come soon, than i'll post pictures of her in a new thread! she's going to be real pretty!

thanks,

frank