Limb length design

[Pat B]

I set my bows up symetrically with the center of the 4" handle the center of the bow. Generally the arrow pass is about 1" or slightly more above center. My bow is centered on the tiller tree and I pull from the center of the tiller string but I leave the lower limb slightly stiffer than the top.

[Roy]

Pat with all due respect here, if the center of the bow is the center of the 4" handle. And the arrow pass is about 1 inch above center, then that means the remaining 3 inches of your handle is below the center of the bow. Now if you pull from the center of the of the handle, which is the center of the bow, and you make the lower limb stiffer. Yes you induce a positive tiller. However when you shoot that bow, your nocking point on the string will be say 3/8th above the arrow rest. So that means the middle finger of your drawing hand will be will be about equal to the arrow shelf, which is 1 inch above the center of the bow. I guarantee you if you pull from the center of the handle, then slide your pull rope over to the right an inch and pull again to replicate your draw hand placement, your going to have a way more positive tiller. Just thinking out loud here:)

[Carson (CMB)]

Sounds like some simply dont like asymmetrical layouts because of the difficultly in reading tiller on the tree.  Here is a method  described by Glenn St. Charles that whips the problem.  layout the bow with same length limbs.  On the tillering tree, the bow is supported in its center ( the center of the handle), and pulled from the center of the string.  Bow is tillered for perfectly even, symmetrical bend, then once you have it tillered out to full draw....unstring the bow, and cut an 1 1/2" - 1 3/4"  off of the lower limb and there you go, a nice positive tiller on an asymmetrical bow.    I still need to try this approach.

[BowEd]

I've been doing my self bows exactly like Pat B like I said earlier.My grip pressure is on the center of the handle while my arrow is leaving an inch to an inch and a half above that with my middle finger doing most of the drawing and my index finger along for the ride.Tiller photos drawn by hand show it's in tiller.That's trillering on the tree from the center of the bow too.

[bushboy]

My method is to get it to short brace and never pull it past 18" on the tree max! Watching all the time to see where the set is happening and try to counteract it.after that it's all about the brace,scraping and exercising between sessions. Lastly I get my photographer to take pic in order to make final ajustments.asemetrical bows r all I have built to date. Again I don't know much except what has worked so far.

[Roy]

All I am saying here is, it does make a big difference where you place your tillering tree pull rope. You should place it as close as possible on the bow string to where your middle finger is going to be when shooting the bow, regardless of your bow hand pressure point. Why would you place the tree pull rope on the bow string, an inch or more below where your going to pull it when you shoot it? Try it sometime, pull from the center of the handle and mark on the wall where the limb tips come down to. Then move the pull rope to the right an inch or so to where your arrow shelf is + figure in a 3/8th higher nocking point on the string. And 3/8th is an average above the shelf for a nocking point. I have read where some guys nocking points are even higher on the string, could that be due to the fact the tiller is way off?  If you move the pull rope more to the right, you will apply even more stress to the top limb and it will bend even more, and the bottom limb will bend less. That equals even more positive tiller.

LOL, just thinking out loud here. I guess there are more ways than one to tiller a bow:) The picture below is a buddy's tree and tiller process. The vertical line on the right replicates the middle finger of his drawing hand. He wants the pull rope to come straight down that vertical line, and he tillers the limbs to do that.  That means the limb timing is perfect. And when he shoots an arrow, the limbs return to brace equally. Look at the picture and see how the pull rope is pretty much where he will draw the bow back when shooting it. Then imagine if you were pulling from the center of the handle on the tree and the difference it would make with the bend/tiller of the limbs.

[artcher1]

Using "that" tillering tree method with my split-finger/medium grip I'd pull your bow's tiller out in 6 shots Roy. My son would ruin your bow's tiller in one shot. Just goes to show that everyone has different needs.

Personally, I don't use a tillering tree to tiller out a bow. I apply a taper to my limbs and let that doing my tillering. I do use a tillering tree to make sure the limbs are bending as was planned. Or for bows with a longer draw than mine. Other than that, all limb exercising is done by hand drawing. Soz you know! Art B

[Dances with squirrels]

That picture there is mine by the way  Thanks for getting me involved, Roy... ya goofball.

I try to stay out of these things because sometimes discussions on various tillering methods are akin to discussions about religious beliefs... we all do and believe differently according to what we're taught and deduce from our own experiences, and in the end, little if anything is solved or changed  for anyone 

I try to remain receptive to ideas, theories, or practical applications that work well for others though, so if yinz are too, maybe we can have a worthwhile discussion here.

The bow above is assymetrical, and is being tillered for a split finger grip on the string and a grip on the handle that applies even pressure across the width of the hand.

Art, yes, we do have varying needs when it comes to tillering... as many different needs as there are shooting variations. The picture above is set-up to replicate MY shooting of a bow designed to my specifications/preferences only. I'd never proclaim it suitable for everyone, or for every bow. That's why I try to make my tillering set-up as versatile as possible.... because I don't always build them the same.

If that exact set-up didn't suit your shooting particulars, or bow design, you could simply move the hook on the string, the pulley down near the floor one way or the other, or change the cradle's shape to replicate your holds... as I've done numerous times depending on the needs of the archer I'm making the bow for. It's actually quite quick and versatile. And if utilized properly, the bow's tiller won't change once it's done. The limbs are tillered in sync with respect to the archer's holds from the first light tugs on the string, until completion... so there's no cause for it to do so... unless there was something inherently wrong with the wood itself that caused change following shooting-in, or it was shot differently than it was tillered for.

I'm wondering how you could pull it out of tiller if it was tillered to how you pull it? Or are you simply saying that the above set-up wouldn't work because it doesn't replicate how YOU draw or design a bow? ...which I completely understand.

[artcher1]

That's the same method I started with DWS. Worked fine for me until I started giving some bows to family and friends. Then the bow's tiller health became an issue because of non-compliance with handling/shooting instruction. So I started pulling my bows from dead center and setting amount of positive tiller needed for each individual shooter.

All I can say is God bless the uninitiated when it comes to these self bows !

[Roy]

Oh so I'm a goofball DWS? LOL, well maybe at times:)  Did I tell ya your bow's tiller sucks? LMAO

We all know by now that none of us will build bows exactly the same. We need to know our style of grip and split or three under requirements before even designing a bow or putting it on the tree. What works for one bowyer might not work for another. One rule I have for wooden bows, is to not let others draw my bow, unless they shoot like I do and have the same draw length as I do. With that said, I still advocate pulling the bow on the tree from where you will pull it when shooting it. I don't care what you set for a positive tiller, if you pull from the center of the handle on the tree, then pull and inch or so higher when shooting, the limbs are going to react differently.

Anyway Art, it's really good to see you posting again, and I hope you are doing well my friend. Did I send you pictures of my first tri lam build? Made this bow for my wife. Osage belly, ERC tapered core lam and boo backed. Gonna make me some more of those.

[artcher1]

Yeah, I think I got that one pic Roy. Nice bow!

Like I said before, I don't use a tree to build/exercise my bows. Only to see how they're bending. Bow scale is mounted from ceiling so I don't need a tree for that either. So, IMHO, the less you use a tillering tree the better.

[adb]

I set my bows up symetrically with the center of the 4" handle the center of the bow. Generally the arrow pass is about 1" or slightly more above center. My bow is centered on the tiller tree and I pull from the center of the tiller string but I leave the lower limb slightly stiffer than the top.

Ditto for me. Couldn't have said it better.

[Dances with squirrels]

"I set my bows up symetrically with the center of the 4" handle the center of the bow. Generally the arrow pass is about 1" or slightly more above center. My bow is centered on the tiller tree and I pull from the center of the tiller string but I leave the lower limb slightly stiffer than the top."

I have a couple questions for those that do it this way... if the center of the bow is the center of the handle and the handle is 4" wide, wouldn't it be impossible to have the arrow shelf/pass any closer than 2" above bow center?

Also, how do you KNOW the lower limb is slightly stronger than the top? By measuring from somewhere on the limb to the string? By judging by eye? The reason I don't rely on these as accurate gauges of relative limb strength is... the slightest difference between the limbs, some of which may not be outwardly visible, means that while we may leave the bottom limb 'appear' stronger, or 'measure' stonger, it might not actually BE stronger, i.e. ACT stronger. ...Hey, there's a chance "leaving the bottom a little stronger" may get you in the ballpark... if both limbs are identical in their inherent strengths, shape, side profile, and while unbraced, both tips start equadistant in relation to the handle, etc... but unfortunately such things aren't always the case.

So that begs my next question... What if there's some type of difference between the limbs themselves, such as, one limb has reflex and the other is straight or has deflex? How do you measure, or eyeball, such a bow throughout the process of tillering so that you KNOW you'll be maintaining limb harmony during the draw and return to brace with specific holds on bow and string? How will the limb's strengths, relative to one another, reveal themselves to you? To what degree of accuracy? And when?

Another question that comes to mind is... Why. Why pull the string from the center of the handle on a symmetrical bow, or ANY bow for that matter, when it's impossible to shoot it that way? Why not simply pull it from where you'll shoot it, when doing so directly reveals, addresses and/or eliminates many of the possible hurdles en-route to an expertly tillered bow? ...of ANY shape or design, or with inherent/internal limb differences. Help me understand. Is it because it's easier to judge the arcs in the limbs?

Some folks are bending and training the limbs, closely critiquing them, and doing their very best to 'tiller' them, while pulling them from a spot on the string 2" from where it will be shot... ever. That, along with the fact that the farther "a little stiffer" is from true limb syncronization, the more erratic the arrow's flight, the more handshock, and the more the resulting wood 'confusion' can help cause tiller shifts during the bow's early life, and who knows what else... because they simply weren't trained to be used that way. So then what? Flip the bow and see if it's any better? hope THEN that the tiller holds? Make adjustments to regain some arbitrary measurement that may have not been the best thing for the bow to begin with? miss target draw weight due to corrections, further confusion of the wood, and perhaps cause unnecessary set in the process?

If I had to do it THAT way, I probably wouldn't want to use the tillering tree either 

The way I'm currently going about it... which I'm not saying is perfect, or the way everyone should do it... has and will continue to evolve as I gain understanding. But as it stands now, when the bow's limbs are out of sync in relation to how the bow will be drawn and shot, I know it on my maiden voyage to the tillering tree, immediately, with the slightest tug on the long string. I'll take it back to the bench and begin harmonizing the limbs right then.... removing wood from any stiff areas I may have noticed... if none were yet visible with so little bend in the limbs... I'll remove wood along the stronger limb's entire length. Once they're in-sync, I'll continue on, doing my thing tillering, bending, training, inching my way down the tree, while keeping an eye on their harmony and making the adjustments needed to maintain it.

If, for instance, I do a little work on a stiff area on one limb, and the hook invariably strays from the line as a result, it often takes VERY little wood removal from the opposing limb to bring them right back in sync. So very little in fact, that it shows me just how delicate and precise an operation this can be, and with that, I don't think there's any way I could get it this close by setting and keeping brace height to a predetermined measurement, by measureing limb travel, or by guessing, which in reality is what "leaving the bottom limb a little strong" is, let alone as-accurately critique and gauge corrections by the 'feel' of the bow's balance during the draw.

Ultimately, the proof is in the puddin'... When I'm done, after reaching full draw with timed, tillered, and excercised limbs on the tree... I have YET to have a bow feel anything but perfectly balanced in my hand upon the first draw. From the first amount of pressure I put on the string as I begin the draw... all the way to anchor... it pulls the handle unequivocally straight into my hand without the slightest hint of tipping either way, and the arrows fly great from the nock point I determined before the bow was begun. I guess such consistant, positive results within a range of bow designs and shapes are what has instilled my trust and confidence in the tillering tree the way I use it... and why I don't have a need to try to 'feel my way' during tillering.

There's a lot going on while tillering, and more than one way to skin a cat most times, but I'm trying to simplify it while remaining versatile by seeking and utilizing the most straight-forward tillering method to achieve syncronized limbs, predictably perfect arrow flight, and the most balanced, smooth shooting bow I'm capable of... with no backtracking to fix tiller shifts, without missing target weight, and without trying to adjust for untimely limbs and the resulting poor arrow flight by moving the nock point around...  regardless of whether it's symmetrical or not, regardless of limb differences, and with a variety of grip and string holds.

Sorry... didn't mean to write a book there   

I should probably be shocked if anyone decided to try to follow me through THAT mess 

I'm goin to the shop to clear my head.... find my 'center', if you will 

[Roy]

Geeze Jeff, took me an hour to read that. But I totally agree wif ya son.

[artcher1]

Had to take a coffee break after reading all that Jeff !

Gotta a question for you though? I've no doubt that you build a fine bow and it holds up quite well for yourself. But how do you tiller a bow for someone with your tillering set-up who requires a good bit of positive tiller because of a heavy low wrist grip?

Like I stated before, I've used the same rig both you and Roy like. But with that set-up the upper limb is engaged and the lower limb just kinda follows. IMO, not the kind of set-up needed for someone who engages both the top and lower limb using a split-finger draw. Drawing the string from the center addresses even strain to both limbs but doesn't address the strain the lower limb feels just outside the fade from the split-finger draw. So I can't see a perfect solution for tillering out a bow when a split-finger draw is involved. Three-under draw.........a different story.

Again, I don't tiller out a bow on the board/tree. Comstock wrote, "good tapering produces good tillering". So my limbs are tillered before they ever see any kind of string. From day one, I've subscribe to the notion that," a bow is built as it stands in the tree". I've never flipped a bow in my life looking for better tiller. Most of my bows have off-set handles w/shelves cut in.

If you strive for even limb strain (drawing the bow by hand and not with a rope) at full draw, you can tiller out any limb configuration by applying the proper profile to each limb. Even limb strain, per type of draw, will, and I repeat, will produce the correct amount of tiller needed for long term tiller health.

This is basically how I approach my bow building. Others approach things differently. No one can say one way is better than the other if it's working for us.

Need more coffee now !