Author Topic: Warbow Tiller check  (Read 708 times)

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Offline Bob W.

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Warbow Tiller check
« on: October 08, 2017, 01:51:16 pm »
Greetings warbow enthusiasts, I spend quite a bit of time over here reading old threads and always look forward to new topics. Between Del and Wills and everyone else on both sides of the pond you guys rock, thank you! Well here is my first contribution to the warbow forum, the ELB I posted a couple years ago don't count even though I've since took the handle wrap off and added horn nocks. This  Warbow was from an 80" live edge yew log that was 1 3/4" thick and 7" wide. The sapwood was toast so i cut it off and sawed a  tapered slat right under it  and glued a  piece of bamboo I tapered right on top with about 2" of reflex. Well Ive been tillering her and would like your opinions and advice. Shes got a mary rose profile or as close as I can get with about 2MM coming off every 6". Right now its 110# @ 28 and thats as far as i have pulled on the tree.  Thanks Bob

Offline Bob W.

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Re: Warbow Tiller check
« Reply #1 on: October 08, 2017, 01:52:18 pm »
Braced

Offline willie

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Re: Warbow Tiller check
« Reply #2 on: October 08, 2017, 02:20:58 pm »
Hi Bob

Are you going for a longer pull?, or have much weight to loose?

from the braced view, my eye sez to scrape a bit on the left mid limb. The full draw pic would be easier to evaluate if it was taken straight on.

Offline penderbender

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Re: Warbow Tiller check
« Reply #3 on: October 08, 2017, 04:05:35 pm »
+1 to what Willie is saying. Cheers- Brendan

Offline Bob W.

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Re: Warbow Tiller check
« Reply #4 on: October 08, 2017, 04:54:06 pm »
Your right Willie a better pic would help ,  is this better? I could take it to 32 if my tiller looks good at 28, does'nt really matter I can only pull it back 20 or so inches now. Thank you  Brendan as well!

Offline willie

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Re: Warbow Tiller check
« Reply #5 on: October 08, 2017, 09:11:29 pm »
I took the liberty of drawing an ellipse over your pic. Not to say that the ellipse is a "correct" shape, but just to aid in seeing symmery if that helps. I do think that your corrections should stay away from the center third. looks like just some minor tweaks to get you good. :)
« Last Edit: October 09, 2017, 10:08:55 am by willie »

Offline Bob W.

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Re: Warbow Tiller check
« Reply #6 on: October 09, 2017, 03:13:16 am »
Excellent, Thank you Willie!

Offline Del the cat

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Re: Warbow Tiller check
« Reply #7 on: October 09, 2017, 04:36:21 am »
Ah! This shows up the problem with the "Ellipse". There are an infinite number of ellipses! And a badly fitting ellipse is worse that pointless.
No one actually has ever defined how elliptical the ellipse should be and that's my big beef with the whole thing! >:(
IMO, arc of a circle or slightly elliptical is fine!
Here's my Ellipse... it's nearly a circle but not quite and it's near perfect IMO :)
Here's another one too, I think they both show the left limb being a hint stiffer which is fine if that's the lower limb.
Del
« Last Edit: October 09, 2017, 04:47:27 am by Del the cat »
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Offline Bob W.

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Re: Warbow Tiller check
« Reply #8 on: October 09, 2017, 04:55:06 am »
Del, that ellipse seems to match up pretty close, the left limb is the bottom so I am good there. Thank you, Bob!

Offline Del the cat

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Re: Warbow Tiller check
« Reply #9 on: October 09, 2017, 05:10:27 am »
Del, that ellipse seems to match up pretty close, the left limb is the bottom so I am good there. Thank you, Bob!
I've just measured the ellipse (in MS Paint) and it's 805 wide and 735 high, so it is a bit elliptical... dunno what to do with those numbers or what they really mean ::) except it isn't a circle  ;D
I think it illustrates how "elliptical" is hard to quantify meaningfully.
Del
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Offline willie

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Re: Warbow Tiller check
« Reply #10 on: October 09, 2017, 10:07:43 am »
Quote
I think it illustrates how "elliptical" is hard to quantify meaningfully.

Del, you bring out a good point, that a method such as using ellipses in paint, in order to judge correct tiller, needs to be quantified. I actually do quantify, in my own notes, the ellipses I use when tillering my own bows. I would need to build a few more with different tillers, and do some comparative shooting, before I could offer any specific suggestion or recommendations.
Quote
No one actually has ever defined how elliptical the ellipse should be and that's my big beef with the whole thing! >:(
Of course , if one wishes to replicate a Mary Rose warbow tiller shape, that would need to be defined somehow. Just out of  curiousity, has anyone seen any study done on the differences between the bows found on the ship (regarding profiles and expected tiller shape)?

Having taken a second look at the pic I posted, I realize that it is not very becoming of Bob's nice workmanship, and will let your more well fitted drawing serve as an example of the usefulness of paint.




 

Offline Del the cat

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Re: Warbow Tiller check
« Reply #11 on: October 09, 2017, 10:21:54 am »
At least one of the MR bows was taken to close to full draw.
I'll look for a pic... Ah, got it, from Robert Hardy's book "Longbow"
Del
« Last Edit: October 09, 2017, 10:33:16 am by Del the cat »
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Offline FilipT

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Re: Warbow Tiller check
« Reply #12 on: October 09, 2017, 10:32:36 am »
When you draw an ellipse for checking tiller, where do you put center of it? At desired draw length?

Offline Del the cat

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    • Derek Hutchison Native Wood Self Bows
Re: Warbow Tiller check
« Reply #13 on: October 09, 2017, 11:25:54 am »
When you draw an ellipse for checking tiller, where do you put center of it? At desired draw length?
I move the ellipse about for best fit, then look at where the centre and "corners" are.
I start off with the top centre roughly at the grip and the drag the corners around.
Del
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Offline stuckinthemud

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Re: Warbow Tiller check
« Reply #14 on: October 09, 2017, 12:02:59 pm »
What software are you using?