positve tiller?

[BowEd]

Hello I'm rather new to the forum here but have enjoyed making bows the last couple of years.Mostly hedge.The question I have is about this positve tiller to the upper limb of 1/8 inch to 3/8 inch on same length limbs.I really don't like the look of 3/8 tiller look at brace height.I've got at least 500 shots into the bows at 1/8 to even tiller.Don't really notice the lower limb fatigueing much.Hav'nt tried the upper limb an inch longer yet.I'm shooting 60 to 66 inch bows 55# to 65#.Shooting shelf is 1 and 3/4 to 2 inch above center of handle.Does anyone have an older bows than mine that have been shot extensively like mine that shows stress?Some bowyers in my area say the self bow won't last more than 5 years.I'm of the opinion that properly taken cared for they can last decades like what is said in the Bowyers Bible books.
Oh another question how from the center on the handle as the bow is braced does a person measure for posive tiller in upper limb?6,8,10 inches?
Ed

[Buckeye Guy]

Welcome to PA
There is on real need to debate these issues as there so many variables that we could go on for centuries trying to work out the answers !!
I will say that the life of a selfbow is determined more by stress than by time if you build a good bow and take care of it you will enjoy it for a long time ! the less stress the more shots if will live for .
Bow building is addictive so you will build more bows than you will need anyway so just just set back and enjoy each one !
I'm not big on worrying about pos -neg or length just go for it !
Now that said I do have a selfbow that is not all that perfectly made by some folks standard but has survived since the 1940s and its still fun to shoot!

[DEllis]

I had a few long wide flatbows go out of tiller and that was starting out with about 1/8 to 3/16 more distance between top limb and string than the bottom. I have had less trouble with narrower bows. I usually try for 1/4 inch difference now with the top limb weaker. It is also better for shooting off the knuckle as the stronger lower limb tends to lift the arrow up off your hand slightly when you release.
I  just slide a ruler along the limb(like a bow square) and measure the greatest distance beween limb and string.......and make sure the upper limb has at least 1/4 inch more. I used to measure about 8 inches out from center, but I like my new method better. Might be wrong but it works for me 
Darcy

[Del the cat]

It is also better for shooting off the knuckle as the stronger lower limb tends to lift the arrow up off your hand slightly when you release.

Hmmm, if the lower limb is stronger, that implies it will return quicker and would therefore tend pull the arrow down wouldn't it?
The tip of the lower limb moves forward and down as it returns...
It's questions like this which make be dubious about the whole positive tiller thing.
Del

[ricktrojanowski]

I started out making bows with a Pos. tiller, usually 1/4".  This was measured at two points.  One 7" above the center of the bow and the other 7" below the center of the bow.  Then when making a Vine Maple bow, it came out even tiller and it looked really good so I didnt want to shed any weight off the top limb to make it a positive tiller and possibly screw it up.  I shot it and liked the way if felt.  Not sure if it was the even tiller, but I've made every bow since then even or just slightly positive 1/8" or less.  I shoot 3 under and I pretty much only make bendy handle bows.

[JW_Halverson]

I will say that the life of a selfbow is determined more by stress than by time if you build a good bow and take care of it you will enjoy it for a long time ! the less stress the more shots if will live for .
Bow building is addictive so you will build more bows than you will need anyway so just just set back and enjoy each one !
I'm not big on worrying about pos -neg or length just go for it !

My worst bow will outlast Buckeye's bow built in the 1940's!  You just gotta promise me you will put it in a bomb proof display case and never ever shoot it!!!  Seriously, Buckeye Guy really hits the nail on the head, stress will eventually kill even the best tillered bows while an ok tillered bow left on the shelf will be around when the ba-jillionth offspring of our cockroaches is studying archeology and discussing the primitive hairless ground apes that died out eons ago.  Just surrender yourself to the addiction and build the best you can, learn from every mistake and celebrate every arrow your bows spit out!

And for the record, I just try to get the bottom limb tip to come in about a quarter inch stiffer than the top. 

Build 'em, shoot 'em, break 'em, build 'em again.

[BowEd]

Thanks fellas.I gotta totally agree about the addiction of making bows.Seems like there's always a thought in mind to make the next one better or different or whatever.I realize I'm gonna get the drizzles worrying about this tiller thing.I just thought I'd throw it out there and keep on making and shootin bows.Giving the upper limb about an 1/8 inch more.Seemed like an opinionated question to me anyway.The last three I've made have been in tiller from floor tillering to the short string so less stress and get every part to work evenly to final draw weight is all I think I can do.Took about 8 or 9 bows to get the floor tillering down to that though.I don't get in a big hurry about it is the key for me.I know its been said before but this forum is GREAT... kind of adding to the addiction.I've go to get a band saw soon.Gettin too old to keep hackin and filing these bows out.I got the Grizzly catalog and am looking at some.I sure could learn faster I know that.Sorry for the large paragraph.

[George Tsoukalas]

I try to tiller the bottom limb slightly stiffer at full draw by a 1/4" or so as I draw it.  I have my beloved take a digi pic. I feel that provides less stress on the bottom limb. Jawge

[DEllis]

It is also better for shooting off the knuckle as the stronger lower limb tends to lift the arrow up off your hand slightly when you release.

Hmmm, if the lower limb is stronger, that implies it will return quicker and would therefore tend pull the arrow down wouldn't it?
The tip of the lower limb moves forward and down as it returns...
It's questions like this which make be dubious about the whole positive tiller thing.
Del

That has not been my experience..........but you are more experienced than me I am sure. All I know for certain is a bow with the top limb stronger will cause the fletching to hit my hand. With the bottom limb being stronger it seems to not even touch at all, or very little. This is with the same nocking point both ways. Maybe I release upside down or sumthin
Or it could be the corialis effect........that's what I get for being on the wrong side of the big pond
Darcy

[Pappy]

I usuall try and get my bottom limb 1/8 to 3/8 stiffer at brace,sometimes it don't work out at full draw but most times it will. I am more interested in full draw but also want it to look even at
brace if possible.A lot of times it depends on the stave,if it is a good clean straight one you can usually do that,if it is twisted and full of humps/snakes and knots you sometime have to go with what you have. As long as the shoot good that is all that really matters. As far as the life of one,they are wearing out some on every shot, a well tillered bow will,I believe last a life time but will take some set over time.Its wood and has a memory with good care you can slow it down but can't stop it.
   Pappy

[crooketarrow]

    When I started shooting trad 6 years before I started building and shooting selfbows. There was'nt the weath of info like now. Sure wish we had inernet then. I only knew the limbs were the same lenth and looked the same. So I learner and thought all bows were tiller that way.
    So I made and tillered all my bows the same. Later I tiller bows with a stiff bottom limb. And knew why you were surpose to do it. But could'nt see doing it that way. Some of my bows were 10 years old and I checked the tiller a couple I had and even had people I'd sold bows to and checked theres and all the tillers were still good. They are bows that had 1000's and 1000's of arrows shot through them.
    I think the lack of excess stress is the key. I never pull over my target weight use a hot box when needed to keep the excess moisture away. I should say start out the a well seasoned  stave. Personally I cant shoot good enough to tell. there's 2 other things I'd for got I never use heat on working parts of limbs and I put the the bow in the hot box for a day before I had the frinish. Just to be sure.Im not sure if it helps because I've never owned a moisture meter. I was just taught to do it this way. It's never hunt.
   Theres no right way,there wood,wood is wood I build bows to hunt with not to look at. I don't try taking the PRIMITIVE out of it. Just have fun and enjoy the things you do and the people you meet along me way.

[Buckeye Guy]

 I don't try taking the PRIMITIVE out of it. Just have fun and enjoy the things you do and the people you meet along me way

Thats what I was trying to say  WELL PUT Crooketarrow !!!

[BowEd]

Thanks again fellas for your input.I agree I have to have a servicable hunting bow,and just take care of it the best I can.I keep a lot of humidity gauges around,and a dehumidifier and try to keep it at 50% but of course the winter time here in southern Iowa brings humidity in this house to 30% which is'nt bad I don't think.I just seal the bow up with only melted beeswax.Sounds to me though I can look forward to 1000's of shots out of each one which as time goes on here is plenty by the amount of bows that are accumulating here since this bow making addiction has taken root.

[snag]

Just to clarify to this dumb newbie....what is 1/4" stiff in the lower limb mean? Does this mean that when measured strung from the fades the lower limb measurement is 1/4" less than the top limb measurement?

[DEllis]

Yes
Darcy