Author Topic: Help with ELB lateral stability --- tiller check  (Read 4290 times)

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Offline k-hat

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Help with ELB lateral stability --- tiller check
« on: April 29, 2013, 06:05:08 pm »
the HBO elb i posted over on the swap forum is giving me some trouble.  Learned the hard way i shouldn't reduce belly wood too much before glue up >:(.  so anyway, it turns out my tips (last 10" or so) are too narrow at the moment (at least for how deep they are), and are wiggling sideways, even with a decent brace.  I've flattened them out quite a bit reducing the belly, but they are not there yet (stable), and i'm afraid i'm running out of wood here.  I also piked to bring the nocks to a wider section of limb. 

Any suggestions on how to remedy this?  What about adding some overlays to the sides of the last 10" or so of the limbs to give a little more width and stiffness?  anybody ever try something like that?  I could make it decorative and pretend i did it on purpose ;)

thanks for any help!
« Last Edit: May 09, 2013, 01:34:37 pm by k-hat »

Offline adb

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Re: Help with ELB lateral stability
« Reply #1 on: April 29, 2013, 06:14:13 pm »
Did you glue in reflex? How narrow is your bow?

Offline k-hat

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Re: Help with ELB lateral stability
« Reply #2 on: April 29, 2013, 06:17:43 pm »
Yup.  Glued in about 1.5" of reflex.  Handle is a hair over an inch wide i think, at nocks i think it's at about 3/8" or just under.  The width taper is fairly constant.

Offline Carson (CMB)

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Re: Help with ELB lateral stability
« Reply #3 on: April 29, 2013, 06:40:43 pm »
I am surprised you are having stability issues with tips that wide.  Are you sure the instability is not from uneveness in belly thickness, from side to side? 
"The bow is the old first lyre,
the mono chord, the initial rune of fine art
The humanities grew out from archery as a flower from a seed
No sooner did the soft, sweet note of the bow-string charm the ear of genius than music was born, and from music came poetry and painting and..." Maurice Thompso

Offline k-hat

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Re: Help with ELB lateral stability
« Reply #4 on: April 29, 2013, 06:53:28 pm »
I'll measure them again when i get home, they may be narrower.  I've been real careful keeping the thickness uniform, but i'll check that as well (was planning on that anyway).  The tips started out fairly square, maybe a hair thicker than width, now they are more rectangular (rounded), but still almost as thick as wide.  When i brace it, i can see and feel the tips move side to side (and the string follows) when i slightly move the bow side to side.

Offline Del the cat

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Re: Help with ELB lateral stability
« Reply #5 on: April 29, 2013, 07:35:12 pm »
Too late.
You should leave the tips wide until it's about 2/3 of the way to full draw, that way you can shift the nocks to one side or another.
Because an ELB is virtually a square profile (as wide and it is deep) it doesn't really care which way it bends, so it's better to keep tips wide early on.
Tie two bits of 'boo together with the thick ends as a grip and it has no back belly or sides... it will bend any way. An ELB is a bit like taht until you have teased it to some sort of tiller.
Here are two posts from my blog which talk about it (I searched the blog for 'sideways bend')
http://bowyersdiary.blogspot.co.uk/search?q=sideways+bend
Del
Health warning, these posts may contain traces of nut.

Offline adb

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Re: Help with ELB lateral stability
« Reply #6 on: April 29, 2013, 07:54:41 pm »
Yup.  Glued in about 1.5" of reflex.  Handle is a hair over an inch wide i think, at nocks i think it's at about 3/8" or just under.  The width taper is fairly constant.

That's your problem.

Offline k-hat

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Re: Help with ELB lateral stability
« Reply #7 on: April 29, 2013, 09:11:37 pm »
I may stick to staves after this lol.  I measured again and the tips are actually right at 1/2"wide by about 9/16" deep, so still have some reducing to do (i thunk i'd removed a lot more than that ??? but oh well).  I'll keep removing thickness until it stabilizes and it'll be the weight that it is. 

thanks for the help adb,cmb, and as well for the link Del.

Offline Del the cat

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Re: Help with ELB lateral stability
« Reply #8 on: April 30, 2013, 04:28:45 am »
I'll measure them again when i get home, they may be narrower.  I've been real careful keeping the thickness uniform, but i'll check that as well (was planning on that anyway).  The tips started out fairly square, maybe a hair thicker than width, now they are more rectangular (rounded), but still almost as thick as wide.  When i brace it, i can see and feel the tips move side to side (and the string follows) when i slightly move the bow side to side.
Well don't move the bow side to side... you'll just encourage it to missbehave ;)
My bows all bend sideways, if I bend 'em sideways ::)
Del
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mikekeswick

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Re: Help with ELB lateral stability
« Reply #9 on: April 30, 2013, 05:01:19 am »
Unless you are going for crazy weight the tips needn't be thicker than 7/16th, even less. Keep your width for now.
It's vital that the layout was plumb straight. Also that the profile is equally rounded.

Offline k-hat

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Re: Help with ELB lateral stability
« Reply #10 on: April 30, 2013, 02:20:44 pm »
I'll measure them again when i get home, they may be narrower.  I've been real careful keeping the thickness uniform, but i'll check that as well (was planning on that anyway).  The tips started out fairly square, maybe a hair thicker than width, now they are more rectangular (rounded), but still almost as thick as wide.  When i brace it, i can see and feel the tips move side to side (and the string follows) when i slightly move the bow side to side.
Well don't move the bow side to side... you'll just encourage it to missbehave ;)
My bows all bend sideways, if I bend 'em sideways ::)
Del

Well i wasn't really doing it on purpose!  lol  :P Just kinda happened when i was bracing.  I left it alone today, but i'll check alignment on it again and make sure the string is tracking true.  As i said i'll keep whittling down the thickness until she's tame, and see what weight she falls at.  I think i'll still hit weight.  Lotsa lessons learned either way, the next one won't be such a pain.

Thanks Mike and Del

Offline Cameroo

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Re: Help with ELB lateral stability
« Reply #11 on: April 30, 2013, 05:40:08 pm »
My advice would be to not worry about the measurements (thickness, width) of the tips.  Just finish tillering and leave the tips (the outer 8 inches or so) stiff until the end.  Once you have the bow tillered out to within a couple inches of full draw,  then start shaving away at the tips until they just start to bend. 

The measurements mean nothing once you are past floor tiller.  The bow decides what it's measurements will be ;)

Offline k-hat

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Re: Help with ELB lateral stability --- tiller check
« Reply #12 on: May 09, 2013, 01:38:39 pm »
Ok i'm getn'r tamed now and out to 23" of draw.  Would like a few more pairs of eyes to check on tiller:



The upper (left) looks a tad stiff in the outer, but i may leave well enough alone. BTW the center 4ish inches i've left stiff, mainly so there's more handle meat.  She's 68" ntn now, i may drop'r down to 67 or 66 to pick up a few pounds.

Offline Del the cat

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Re: Help with ELB lateral stability --- tiller check
« Reply #13 on: May 09, 2013, 03:30:39 pm »
Depends what sort of tiller shape you want.
I think the outer thirds could flex more, and if you want full compass, the centre (middle third) could flex a whisker.
Just noticed the strings seems to be attached halfway donw the limb! (OK a sight exag')
Right looks a bit stiffer than left.
It's hardy going to be a longbow if you reduce it to 66" !
Del
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Offline Joec123able

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Re: Help with ELB lateral stability --- tiller check
« Reply #14 on: May 09, 2013, 03:35:48 pm »
What's up with the extra lenth on the tips ?? I think you need, like del the cat said, to take wood from the outer thirds on both limbs
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