3 Under Tiller

[huntwithastick]

What is the main difference in tiller for a bow tillered for three fingers under?

[Pat B]

With a glass bow it probably doesn't matter. It's more a matter of nock placement.  With a wood bow the bottom limb should be a tad stiffer.

[dutchwarbow]

with 3under you're grabbing the string more to the center than with split fingers. The latter makes you grab it higher, and thus makes your bow need a stiffer, lower limb.

Correct me if I'm wrong

Nick

[stickmonkey]

That is my understanding as well Nick.

[bjansen]

I had the same question...I got some really good feedback ...check this out

 http://tradgang.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=125;t=000553

[huntwithastick]

Guys,

Thanks for the comments.  Most of my bows come out in 1/8" to 1/4" range in difference between top/bottom limb.  I guess if I want to shoot three under they are in the ball park.

Have a good one!

[Shaun]

Split finger standard is 3/16" positive tiller (more gap at brace height on the top limb as measured at the fades) and three under is to have even tiller top and bottom.

[DCM]

In the intervening months since the thread bhanson cited I've seen this discussed, and a very notable bowyer's comments.  In essense, at least in glass bows, the conclusion was tiller (measure) doesn't matter, as bhanson commented.  Rather nock point can be used to compensate for whatever the tiller is.  But the dogma has always been what Shaun wrote.

When I shoot a bow tillered positive using 3 under, they are nearly always louder than using split finger.  Not sure why, but perty sure it means something, even if not significant.

On selfbows I'm convinced the more balanced (the less positive tiller required) the better in terms of not overworking the upper limb and having it become set and weak over time.  I tend to do this with geometry, putting arrow pass closer to center, rather than positive tiller.

[bjansen]

In my experience, tiller in the glass bows I have built is equally important.  DCM, since you provided my the insight back in the orginal post...i have  since tillered almost all of my new bows with zero tiller (for 3 under)...and have gone back and adjusted a few of my previous bows, noting that zero tiller (for me with 3 under shooting) produced less noise and reduced handshock.

[DCM]

Sorry Brad, it was Pat who said tiller doesnt matter on glass bows.  I think everyone understands it matters, just a question of  how much.

[Glenn Newell]

Regardless of whether your bow has equal length limbs of a shorter bottom limb any bow should be tillered from where the bow is held in the hand and where arrow is nocked. If you don't you will never see what is happening to the limbs when being drawn. It's a waste of time pulling a bow down on the tiller board from one position and then nocking the arrow and drawing from another position, you will pull the bow out of tiller srtaight away. Even glass bows like to be tillered from where the arrow will be nocked, it does make a big differance to how they shoot...Glenn...

[2treks]

Tiller is key with all bows.The glass will just keep you from pulling a glass bow "out" of tiller. As Pat said nock placement can work, it will be high. I have seen it as high as ONE INCH above the shelf. As noted by Shaun, a positive tiller for split and an even tiller for 3 under is the norm. design and shooting style can play into this as well. As it can with most aspects of shooting/building.

[dutchwarbow]

I've tested it on a 54" bow, wich I drew to 30". Once while holding the bow extremely high, once when holding it very low.

when I grabbed the string HIGH, the lower limb bent much more. -> it's stressed more, and needs to be stiffer

when I grabbed the string LOW, the upper limb bent much more. -> it stressed more, and needs to be stiffer.

Nick