Author Topic: An idea for ash bow dimensions & tillering tips  (Read 1116 times)

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Offline WillS

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Re: An idea for ash bow dimensions
« Reply #15 on: October 02, 2017, 01:08:35 am »
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Is that fairly typical most warbow designs?

Ruddy, I am not questioning your design, I honestly have no idea about what is typical with most warbows. I quess the tables I see (such as yours and the others mentioned) are always qualified as starting dimensions. It would be interesting to hear from those who have started with such tapers, and have turned them into working profiles. :)

The dimensions Ruddy has written down are actually perfect for a finished bow with slight elliptical tiller.  If you were to make the stave EXACTLY to those numbers, and the timber didn't have any unusual dips, flaws or weird areas of denser wood, then theoretically you wouldn't have to tiller the bow at all. 

Offline WillS

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Re: An idea for ash bow dimensions
« Reply #16 on: October 02, 2017, 01:09:52 am »

I used the 100-130lb category, and it's pulling 110lb on the tiller tree at the moment.

That's great, interested to see where it ends up but looks like you're on the money with that one!

Online FilipT

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Re: An idea for ash bow dimensions
« Reply #17 on: October 02, 2017, 02:59:43 am »
Interesting thread and dare I say synchronicity, as I will start roughing out ash bow in about hour or so!

Offline Ruddy Darter

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Re: An idea for ash bow dimensions
« Reply #18 on: October 02, 2017, 06:23:18 am »
Good going with that FilipT :BB,

 R.D.
« Last Edit: October 02, 2017, 08:03:05 am by Ruddy Darter »
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Online FilipT

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Re: An idea for ash bow dimensions
« Reply #19 on: October 02, 2017, 09:41:43 am »
Tnx, you too. Today I removed bark and put width dimensions, tomorrow it will got basic roughing out. But I must say wood was cut two days ago so it will be a while since I start to tiller it.

Offline willie

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Re: An idea for ash bow dimensions
« Reply #20 on: October 02, 2017, 09:57:00 am »
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The dimensions Ruddy has written down are actually perfect for a finished bow with slight elliptical tiller.
That was my guess also, Will. Seems like many warbows are built by first establishing a depth taper and then side tillered to finish, at least more so than than with other type of bows, where most tillering is done on the belly after a width profile is established.

I often see warbow dimensions presented in this tabular form, and presume that many of the mary rose bows measurements are tabulated in the same way? Not having the ability to review these dimensions, or other tables often mentioned by the warbow community, I was curious if the additional thickness tapering in the outers is........ typical, common, uncommon or  rare?

Offline Ruddy Darter

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Re: An idea for ash bow dimensions
« Reply #21 on: October 04, 2017, 08:26:25 am »
I finished getting the stave worked down to 40mmx30mm ready to start working it to dimensions.
The stave is relatively straight save for a little wiggle inner mid limb. One question I have is the slight D-flex on the limb nearest...would it pay to heat this straight after working it down or would it be more trouble than its worth as it might throw me by creeping back in when I tiller?...would I be better off leaving it alone?
 Thanks for any advice,

 R.D.
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Offline WillS

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Re: An idea for ash bow dimensions
« Reply #22 on: October 04, 2017, 10:12:31 am »
Heat treating to correct tiller is done once the bow is braced, not before.

Before bracing, you want to try and preempt issues like reflex and deflex.  Reflexed areas are left slightly thinner, deflexed areas slightly thicker.

So basically, leave maybe 2mm extra thickness on the belly in that deflexed area, take everything else down to exact finished dimensions and check, check and check again the eyeline, looking for swells, dips etc that shouldn't be there.  Get all of those sorted, until you're absolutely sure the bow is ready (I tend to ask myself if I'd sell it and if the answer is yes, it's ready!) and then get the horns on, brace it up and see what's happening. 

That's the stage where you bring in the heat gun, charcoal etc to temper the areas that are bending too much at brace height. 

Offline Ruddy Darter

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Re: An idea for ash bow dimensions
« Reply #23 on: October 04, 2017, 10:20:02 am »
O.K. thanks, I'll just leave it be then...dont want to chance complicating matters,

 R.D.
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Offline willie

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Re: An idea for ash bow dimensions
« Reply #24 on: October 04, 2017, 10:35:45 am »
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deflexed areas slightly thicker.

Will, would that mean that you must also leave the thicker area appearing to be stiffer in the bend profile when tillering?

Offline Ruddy Darter

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Re: An idea for ash bow dimensions
« Reply #25 on: October 04, 2017, 11:35:39 am »
 It also look like I'd be needing to keep it a little stiffer around that area due to a knot (which may be worked out or need a little fill) and that slight wiggle starts just about there.

 Something I'll bear in mind, thinking out loud, maybe I'll flip the very tip a little that end with heat to even out if needed, I'll wait and see how it goes.

 R.D.

 
« Last Edit: October 04, 2017, 12:06:48 pm by Ruddy Darter »
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Offline WillS

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Re: An idea for ash bow dimensions
« Reply #26 on: October 04, 2017, 11:45:11 am »
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deflexed areas slightly thicker.

Will, would that mean that you must also leave the thicker area appearing to be stiffer in the bend profile when tillering?

No, they should look like they're bending the same as the rest of the bow.  If they're already deflexed they're already essentially bending. 

Offline willie

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Re: An idea for ash bow dimensions
« Reply #27 on: October 04, 2017, 12:34:39 pm »
No, they should look like they're bending the same as the rest of the bow.  If they're already deflexed they're already essentially bending. 

interesting approach to deflex. Should it look like they're bending the same as the rest of the bow at brace or full draw?

Offline Del the cat

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Re: An idea for ash bow dimensions
« Reply #28 on: October 04, 2017, 11:22:11 pm »
Just my opinion of course... but:-
NO!
Any features in the unstrung bow should till be evident at full draw to some extent, so a limb that has a little reflex (unstrung) should appear a tad stiff at full draw. A limb with slight deflex should appear a little weak at FD.
If you thin down the reflexed limb and leave the deflexed limb stiff, you will end up with a bow that looks perfect for five minutes until the reflexed limb starts to go even weaker, then chrysal and collapse.
Del
« Last Edit: October 04, 2017, 11:25:40 pm by Del the cat »
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mikekeswick

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Re: An idea for ash bow dimensions
« Reply #29 on: October 05, 2017, 12:01:11 am »
Just my opinion of course... but:-
NO!
Any features in the unstrung bow should till be evident at full draw to some extent, so a limb that has a little reflex (unstrung) should appear a tad stiff at full draw. A limb with slight deflex should appear a little weak at FD.
If you thin down the reflexed limb and leave the deflexed limb stiff, you will end up with a bow that looks perfect for five minutes until the reflexed limb starts to go even weaker, then chrysal and collapse.
Del

Yup :)
You are trying to make the strain even along the limb. Regardless of what the limb is doing it needs to feel even strain at full draw.....or else problems are round the corner!