Author Topic: tillering tips  (Read 1687 times)

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Offline bradNZ

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tillering tips
« on: August 18, 2017, 05:51:54 pm »
Hey guys,

I finally had a second attempt at a selfbow. In my first attempt I hit decayed wood and turned it into firewood. This attempt seems to be going better.

So I'm partially way through tillering and would like some advice before I get to full draw. at the moment it's pulling about 50lb at 23". How does the tiller look to you guys? Should I just keep scraping until I get to 28"? I'll be happy with 50-55lb @28". I should mention that I plan to heat treat the belly a few inches before hitting 28".

How it is now, when I unstring it there is noticeable string follow, however it slowly moves back to close to straight.

One other thing, tillering raised a question for me in regard to draw length. I know draw length is normally measured to the back of the bow. However wouldn't this mean that it would change from bow to bow depending on the thickness of the handle? I have marked my tiller tree setup so it measures the distance from the belly of the bow. I was just wondering how you guys measure your draw length on the tiller tree?

I should mention this is made from Kanuka, which is a New Zealand native. When I split it I didn't leave enough meat for the handle so had to glue one on.

Cheers

Brad

Offline Badger

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Re: tillering tips
« Reply #1 on: August 18, 2017, 07:36:43 pm »
  The tiller looks pretty good but if it is already taking set you don't need to pull it to 50# anymore. That is way too heavy for that bow. Try 40#. Set will just keep getting worse and you are not even close yet, maybe 35#. Is the wood dry? Draw length on a trad bow is measured from the deepest part of the grip and you add 1 3/4". So a 28" draw is 26 1/4" from the deepest part of the grip regardless of how deep the grip is. Primitive bows are usually just measured to the back of the bow regardless of grip.

Offline bradNZ

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Re: tillering tips
« Reply #2 on: August 18, 2017, 09:53:53 pm »
Thanks Badger, damn I was hoping for a hunting weight bow! Oh well, next time I hope. I do have my doubts about if the wood is dry enough. I cut the tree down about 9 months ago and split it that day, but it has been reduced to near bow dimensions for about 3 months so thought it would be dry enough, however it is winter here and we have have had a lot of rain. I've been keeping it in the hot water cylinder cupboard to try and fix that... I have a cheap moisture meter with two pins on it that you jam into the wood I bought of aliexpress. It says 15 % but I don't know if it is accurate!

The bow is 70" nock to nock and about 2 inches wide at its thickest part.

Thanks again for the help.

Offline Badger

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Re: tillering tips
« Reply #3 on: August 18, 2017, 11:20:49 pm »
  Maybe dry it out just a bit more 15% will take a lot of set. Try and get it down to at least 10.

Offline bradNZ

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Re: tillering tips
« Reply #4 on: August 19, 2017, 12:39:47 am »
I'll do that. Today I measured the moisture in the rafters in my garage and they read 15%. Then I measured the moisture in the shelves in my hotwater cupboard and they were about 6%. Initially I didn't trust my moisture meter but after todays test it sounds about right.

I think you might be onto something Badger. I'll leave it in the cupboard for a few weeks and see how it goes from there.

I've been told Kanuka responds well to heat treatment so fingers crossed that will help too!