Tillering help: my first non-circular tiller

[Freeflynick]

Hi guys!
A little while back I posted pics of a bendy glue-up idea I had for a hickory backed ipe bow. The consensus was "Don't do it" and.....Yeah. I did it anyway, because I was really eager to do a non-circular tiller bow because they are so visually pleasing.

So here I am, getting to brace height and no clue how I am supposed to go about getting a good tiller on a non-linear bend, so ANY advice you can give me on what I should be looking for, tips on how to get a good tiller, etc., would be greatly appreciated.

I have attached some photos of where I am at the moment. It is obvious from the pic of the braced bow on the floor that the right side is stiffer, and I THINK i general I need to take off material mid-limb on both sides? I aim to have this quite a light bow - maybe 25# - 30# since as a noob I need to focus on technique.

I would really appreciate your guidance on this one - it is bow #6 for me.

Cheers!

Nick

[bownarra]

You appear to be bending too much out of the fades.
Get both mid limbs to tips working more.
You should be seeing the transistion to reflex straightening more and the reflex in the tips should be getting near to straight at full draw.
These bows are tricky to tiller. It would help to get a solid background behind your tree to make it easier for people to judge the tiller.

[Pat B]

I agree with everything bownarra said and especially about the solid background. The way it is now it's hard to see details in the bow's profile.

[DC]

They are tricky to tiller. With a straight bow it's relatively easy to see how much each part it bending. With an RD each bow is different. It all goes back to the shape of the unbraced bow. You've probably read on here that if you have a wiggle in a straight bow the final bend should still have that wiggle. An RD is no different. To get a handle on it I put a straight unbraced bow with good tiller on the tree and traced it on the backboard. Then I braced it and traced it again. Then I pulled it to about half draw and traced it again. Then I measured every 6" from the unbraced line to the half draw line and wrote down those numbers. Then I put the RD on the tree and repeated the process. The numbers I got for the RD should be close to the numbers I got from the straight bow. Then you have to decide whether you want circular or elliptical tiller and modify your numbers accordingly. You probably just have to do this once just to get an idea of what the FD RD should look like. Hope you understand all this drivel

[Freeflynick]

Then I measured every 6" from the unbraced line to the half draw line and wrote down those numbers.

If you mean you measure out horizontally 6" then take the measurement verically between unbraced and half draw, then, yes, I understand and that makes sense. I will try this - thanks!
That was part of the thinking behind my rainbow mirror! The mirror was there before we moved in and it is the only available wall to tiller on, so I thought the tape lines would help judge how far the limbs were bending on each side, which they do, but as bownara and Pat B both point out, it doesn't really help as it somewhat confuses the eye when trying to see the full picture. Another one of my bright ideas that didn't work as planned!
Thanks to you all for your input - I will focus on getting those mid-limbs and areas just before the tips bending more.
Cheers
Nick

[DC]

[quote author=Freeflynick link=topic=68616.msg963097#msg963097
If you mean you measure out horizontally 6" then take the measurement verically between unbraced and half draw, then, yes, I understand and that makes sense.
[/quote]

Yup. It may be that RD's want a different tiller, I haven't got into that. This just make sure that they are at least bending everywhere.