Different Amounts of Set Between Limbs (Pics added)

[BarredOwl]

If one limb of a bow takes a little more set than the other is it simply a sign of a less than perfect tiller?  Or does it just happen sometimes? 

It is the bottom limb of the bow in this case.  I did have it slightly stiffer than the upper limb when I started shooting it.   I have finish drying on it right now and will take a FD photo and compare to the FD photo when I started shooting it.  I probably have 100 - 150 shots through it.  The overall amount of set doesn't seem to be changing.  I check it by putting the bow up against the wall right after unstringing and several hours to a day later and it doesn't appear to be changing between shooting sessions.

[Badger]

  Not sure if this is your issue or not but I used to store my bows in a big plastic drum. The bottom limbs would have higher moisture than the top limbs and would take set if I pulled them out of the drum and started shooting them without giving them to time to equalize.

[Drewster]

I had that problem with a bow recently.  It is a billet bow.....sister billets.  The bottom limb took more set than the top limb.  I heat treated the bottom limb twice but nothing seemed to fix the issue.  A piece of wood with a mind of its own I suppose.  Ya gotta love figuring out the mystery of a piece of wood :-)

[BarredOwl]

Well at least the first two replies didn't overwhelmingly say it was a tiller problem for sure so that has me feeling a little better.  I noticed it was harder to chase the ring on one end of the bow compared to the other.  Didn't pay attention at the time to which side it was.  If I ever notice this phenomenon again I will mark which side it was.  I suppose there could easily be that much variation in qualities of the wood in a 55" run of osage.   

I did tiller this bow during a wet rainy spell and I kept thinking I should probably wait for a week with lower humidity, but I was making good progress, I had the time, and didn't have the self discipline to wait for drier weather. 

[Tuomo]

I think it is one kind of tiller problem. What you see in tiller tree is not what you get in real full draw. Take full draw pictures in tiller tree and in your hands. I really suspect that bottom limb is bending more in your hands than in tiller tree.

There is two reasons. The pressure points (in handle and in string) you use in tiller tree are not the same than when you are really drawing the bow in your hands. Or, the pressure points are correct but you interpret the bending of the bow in the tiller tree wrong way.

Depending your grip, is it high or low, the pressure point in the handle can vary quite much. With high wrist grip the pressure point is close to arrow rest (if you have one...) and with very low grip, the pressure point can be up to 7 centimeters lower. And it really affects to the tiller!

Of course, the reason can be that bottom limb is shorter than top limb, so it is bending more -> more stress -> more set.

If you watch full draw picture here and there, bottom limb is bending more almost always. It is also common that bottom limb is taking more set, in fact, it is nothing special. Of course, it should not be so!

[mikekeswick]

Agreed Tuomo.
I don't really use the tiller tree now after 20 inches. all the rest of my tillering is done by hand drawing and keeping an extremely close eye on any set the bow is taking.
Set in one place or one limb shows 100% that that spot/limb is taking more strain than it should.
Before starting tillering I strongly recommend tracing the side profile of the bow onto something. So every time you unstring it after exercising you can see immediately (before it relaxes) where the set is. Set is your teacher and friend!

[Jodocus]

I regularly encountered this as long as I stored my staves standing upright. It's like badger said, but without the drum. Bottom limb just had more moisture.

[Tuomo]

I do not believe to the theory that bottom limb is more moist, if bows are stored upright and bottom limb is at floor. We have discussed this subject here in Finland. So, I made a test. I checked relative humidity at floor and at ceiling - no measurable difference. Checked it many times, same results. In normal home air is circulating so much that relative humidity is the same all over, unless you have some kind of very special conditions - like plastic drum, etc.

[Dances with squirrels]

Many people draw their bows on the tillering tree different than they do by hand, then they're surprised when the tiller shifts as the bow is used. I have my tillering tree set up to replicate my holds on bow and string, pull the string relative to a specific nock point height I'll use when it's all done. If the limbs are sync'd, tillered, and exercised relative to that nock point and me, then as I use it, there are no changes for the wood to account for, no reason for one limb to begin taking more set than the other.

I use my tillering tree right through to the very end... it is proven and I trust it entirely. I'm pretty anal about relative limb strain/balance. I don't guess, and I don't like unpredictability in my bows.

[Del the cat]

It seems to be always the bottom limb, which is why we tiller 'em a bit stiffer.
I agree about drawing on the tiller tree.. it should be placed to replicate a real draw.
To test the "store 'em upright" theory... simply store 'em upright but upside down simple.
I've only ever had it happen really bad, the once and that was an Ash primitive... (did I ever mention I don't like Ash? )
Heat treating the lower limb can help get it back in balance.
Del

[BarredOwl]

I did tiller by hand at the end.  My bottom limb was probably just not stiff enough compared to the top one when I started shooting it.  I am nervous about weakening the upper limb now and overshooting then having to weaken the bottom and end up giving up too much weight. 

I assume the problem will only get worse if I don't do something about it?   I thought I had really gotten this one right.  Guess that's part of the process.  I hate to put heat to it at this point so if anything I will look at the tiller once the finish dries and sharpen up the scraper probably.

[Del the cat]

Bettre to heat treat it now before it gets any worse. You can ease it back to straight as it's warming up too.
I wouldn't worry about finish.... until the bow is finished  
Del

[BarredOwl]

The wood is Osage.  How dark should I try to toast it to have chance at stiffening it up a little?  I assume not necessarily real dark at this point.  I assume I will need to sand any finish off first.  I will also try to post some photos.  I hate to ruin it now but if it's not meant to be it's just not meant to be.

[BarredOwl]

Also I assume I will need to sand all finish off ( back, sides, and belly) before applying any heat? 

[George Tsoukalas]

How much set has your bow taken, BarredOwl and what is the difference in set between the 2 limbs? Jawge