For better limb tiller:

[Gaust]

"If one limb of your bow stave has more natural deflex than the other, and if the limbs are of equal length, make the limb with the greater deflex the bottom limb.  Failure to do this could cause the lower limb - which is under greater stress - to bend too much once the bow is broken in.  This problem is more pronounced with wide-limbed bows." - Paul Comstock

After reading this in TBB II, I was wondering about the recommendation that you tiller approximately 1/8" - 1/4" positive measurement on the upper limb, when the bow is to be shot split fingered.  Would Paul's statement contradict this?  I mean would you ignore this rule when you have a limb with more natural deflex than the other?

George

[kleinpm]

I ignore most of the "rules". I haven't noticed much difference when a limb has a little deflex.

If one limb has reflex and the other deflex, I try to get them to match or make them both straight with heat. I have a hard time tillering a bow with two limbs bending opposite directions.

Patrick

[Josh B]

Good catch!  If you have the lower limb slightly deflexed or with less reflex than the upper, that is serving the same purpose as the positive tiller.  You want to use one or the other.   Using both is like doubling down and will cause problems.  When I heat in reflex, I always heat in 1/2" more reflex in the upper limb.  This will compensate for the strain difference, maintain limb timing and give a nice symmetrical appearance at brace and fulldraw.   The positive tiller does most of that with the obvious exception of the symmetrical brace.   Josh

[George Tsoukalas]

These days I tiller the limbs even and preferably with the bottom limb slightly stronger, at full draw.


I check in front of a mirror, window at night or preferably a digi pic.


I generally prefer to put the stronger limbs, limbs with problems, etc on the top.

Jawge

[PEARL DRUMS]

I think Paul's statement is rubbish. On even length limbs I will always use the stronger/more reflexed limb on the bottom. Never the top....ever.

[mikekeswick]

I think Paul's statement is rubbish. On even length limbs I will always use the stronger/more reflexed limb on the bottom. Never the top....ever.

I always use a deflexed limb as the lower. 
The goal no matter what the limbs are doing along the way is to have equal strain on both limbs at full draw. This means making the lower a little lower stronger due to the forces you place on the limbs during the draw not being equal. A bow is a little like a see-saw with different lengths eitherside. You need to have a heavier weight on the shorter side.

[PEARL DRUMS]

Funny how that works eh' Mike?...

[Josh B]

I think Paul's statement is rubbish. On even length limbs I will always use the stronger/more reflexed limb on the bottom. Never the top....ever.

Interesting .   With one limb reflexed more than the other, which limb has to bend further to reach brace?  The higher reflexed limb....correct?   So...if its bending further to equal the strain of the less reflexed limb,  which one is stronger?   Josh

[PEARL DRUMS]

My guess is the more reflexed limb..... I always thought we wanted to put the stronger limb on the bottom? Something is fishy around here.......

[mikekeswick]

Umm....it must be something to do with the angle of dangle....or magnetic fields....or something 


At the end of the day as long as you don't overstrain the wood and listen to/watch what it tells you....it'll all be good 

[Josh B]

Nope.  The reflexed limb is storing more energy, but it has to travel further to equal the bend resistance of the less reflexed limb.  This means the less reflexed limb is the stronger.   Think of it like this.  If you have to bows that are nearly identical.  One is drawing 50#@26" the other is drawing 50#@28".   The bow drawing 28" is storing more energy at 50# than the other.  However, if you draw the other bow out to 28" it will be pulling more weight(stronger).  See the difference between energy storage and strength?  Josh

[Sasquatch]

Don't most people even out the limbs with heat/steam before they start?  Wouldn't this solve the problem of the pre-deflexed limb ?

[JonW]

Nope.  The reflexed limb is storing more energy, but it has to travel further to equal the bend resistance of the less reflexed limb.  This means the less reflexed limb is the stronger.   Think of it like this.  If you have to bows that are nearly identical.  One is drawing 50#@26" the other is drawing 50#@28".   The bow drawing 28" is storing more energy at 50# than the other.  However, if you draw the other bow out to 28" it will be pulling more weight(stronger).  See the difference between energy storage and strength?  Josh

I agree Josh because I have just recently noticed this myself on a bow I was working on. I generally try not to use that much brain power though.

[Gaust]

For split-fingered shooters, the bottom limb should be the stronger of the two.  To balance the strain on the limbs, that's a given, right?  But I can see the argument that a naturally deflexed limb would be stronger because it is less strained at full draw, meaning it doesn't have to work as much as one that is more reflexed.  Example: If you were stronger than I am to begin with, you wouldn't have to work as hard at the same task.  But on a bow, if you were able to pull each limb separately, the more reflexed limb would be the stronger one.
George

[PEARL DRUMS]

Got way too deep for my pea brain! Ill just keep doing what I do for whatever reasons I do it!