Hazel bow tillering and set question

[apollinaire]

Hello!

I recently did a retiller of a hazel sapling bow I made about a year ago. I increased the draw length and made the tiller more evenly.
It's not perfect, but it must be one of my more successful tillers.
This is my fifth or sixth bow, and I have worked with hazel and ash. I think hazel is a very forgiving wood and quite good for beginners.
It looks pretty much like the sapling it once was. I decided to keep the bark on as that's easier than establishing a growth ring.

The bow and my high-tech equipment, not at full draw.


It has however, in the tillering process taken a lot of set and my question to you is if you have any tips to keep this from happening? (apart from using dry wood)
Is it all about being careful during tillering?

And finally, how does set affect a bows performance? Is it less efficient?

[Del the cat]

Yup Hazel is great wood.
Nice bow.
Heat treating the belly will help avoid set. Keeping it at least 2" wide and fairly long will also help.
A bit of set does no harm IMO. One of my fave 'go to' bows is a 40# Hazel bow V similar to that (but no levers), with a good bit of set. Shoots smooth as silk and puts an arrow where you are looking.
Personally I think levers are a waste of working limb length and just stress the inner limbs more... maybe that's why I've never made one yet. Could be I'm talking out my backside tho' as I do tend to go for nice slim tips.
I love Bark on Hazel bows.
Here's a more recent one of mine with some video of my Son shooting it. I went a tad longer that the one with set.
http://bowyersdiary.blogspot.co.uk/2012/10/bark-on-hazel-finished-pics.html
If you trawl back through the blog you can see the build. I don't think I heat treated that one. There's a few Hazel bows on my website (Delsbows) too including the "One Hour Bow" 
A bit of set does lose performance in terms of speed, but can add smoothness. I think if you have no set at all then you aren't working the wood hard enough and are thus carrying excess weight. I've successfully heat treated bows that have already taken set. Search for 'Hickory Challenge' on my blog.
Where is the set? IF it's spread evenly, then the tiller is good, maybe just too much draw length for the bow. Heat treating can gain a fair bit of poundage (up to maybe 10#)... this will allow you to further thin the limbs to adjust both tiller and poundage to match the longer draw.
Looks to me as if the inner limbs are working harder than the outers.
Del
(BTW. Are you in the US, UK, or somewhere else?)

[dbb]

The most repeated advices here about tiller is
Never draw beyond your intended targetweight.
never draw more than you need to see what needs to be done.
 Or something like that,it helped me a lot atleast

[Joec123able]

Well don't let your bow sit at full draw on your tillering thing

[UserNameTaken]

How much set did it take? Also, what are the dimensions of the bow?

[apollinaire]

The levers were kind of an improvisation as i wanted to make the tips as slim as possible, without having them bending. I read somewhere that when tips bend too far, you run the risk of them releasing too soon, so the arrow leaves the string before the rest of the bow has added its energy. They could be the cause of the inner limbs bending more though.

You’ve got a really nice blog there, Del! There’s a lot of useful information.

There’s at least 10 cms (4 inch) of set, relatively evenly spread. Heat treating is no option on this one as I made it in my student’s flat in the city. I can however try it on an ash bow with a similar problem I made at home. I'll post a picture when I start working on that one again. Unfortunately, exams are coming up. I’m from Belgium btw.

Thank you for the info!

[Del the cat]

I'd be interested to see a view from the back. It just looks to me as if the levers are too deep. Remeber stiffnes is related to the cube of the thickness.
So if the levers are say 1/4 the width of the working limb, they only need to be about 1.6 times as thick.
(e.g 1.6 cubed is just over 4). whereas yours look more than twice as thick... so that's extra weight.
Del

[apollinaire]

I didn't know that. I left hem rather big as I just wanted to be safe. According to your calculations I can definitely take some weight off.
I can post pictures some time next week.

Thank you!

[Badger]

  How long is the bow and what is the physical weight of the bow?

[Badger]

  I would look at that bow as a lesson. You had to have gotten that set 1/4" at a time until it reached 4". The first 1/4" of set you got was telling you the bow was over stressed either in one place or evenly across the limbs. The first 1/4" of set was telling you to either find a place you can get some more limb bending or lower your target draw weight. The next inch of set was screaming at you to do this. Just look at it as a good lesson that we all go through at some point.

[mikekeswick]

  I would look at that bow as a lesson. You had to have gotten that set 1/4" at a time until it reached 4". The first 1/4" of set you got was telling you the bow was over stressed either in one place or evenly across the limbs. The first 1/4" of set was telling you to either find a place you can get some more limb bending or lower your target draw weight. The next inch of set was screaming at you to do this. Just look at it as a good lesson that we all go through at some point.

Very true! Take this advice!
A quick assesment from me - it's bending too much inner limbs. It was likely still too wet. Heat treating will help a lot but only if you've got the basics dead on. Your tips only need to be 1/8th of an inch thicker to not bend! Cut them off now! Stress goes down the closer you get to the tips so you can make them 3/8ths wide and just that shade thicker and they will be in zero danger of breaking.
Good luck on the next one!!

[apollinaire]

Thank you very much for the advice!
I'll keep this in mind when making my next bow.