Primitive Archer

Main Discussion Area => Bows => Topic started by: k-hat on April 29, 2013, 06:05:08 pm

Title: Help with ELB lateral stability --- tiller check
Post by: k-hat 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!
Title: Re: Help with ELB lateral stability
Post by: adb on April 29, 2013, 06:14:13 pm
Did you glue in reflex? How narrow is your bow?
Title: Re: Help with ELB lateral stability
Post by: k-hat 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.
Title: Re: Help with ELB lateral stability
Post by: Carson (CMB) 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? 
Title: Re: Help with ELB lateral stability
Post by: k-hat 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.
Title: Re: Help with ELB lateral stability
Post by: Del the cat 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 (http://bowyersdiary.blogspot.co.uk/search?q=sideways+bend)
Del
Title: Re: Help with ELB lateral stability
Post by: adb 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.
Title: Re: Help with ELB lateral stability
Post by: k-hat 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.
Title: Re: Help with ELB lateral stability
Post by: Del the cat 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
Title: Re: Help with ELB lateral stability
Post by: mikekeswick 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.
Title: Re: Help with ELB lateral stability
Post by: k-hat 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
Title: Re: Help with ELB lateral stability
Post by: Cameroo 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 ;)
Title: Re: Help with ELB lateral stability --- tiller check
Post by: k-hat 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:

(http://i1216.photobucket.com/albums/dd374/k-hat/TxLBtiller23.jpg) (http://s1216.photobucket.com/user/k-hat/media/TxLBtiller23.jpg.html)

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.
Title: Re: Help with ELB lateral stability --- tiller check
Post by: Del the cat 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
Title: Re: Help with ELB lateral stability --- tiller check
Post by: Joec123able 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
Title: Re: Help with ELB lateral stability --- tiller check
Post by: k-hat on May 09, 2013, 04:16:02 pm
The extra length is what i just haven't gotten around to cutting off yet ::).  I started it out extra long just in case (good thing i did), and have moved my temp nocks in to where they are now.

ya i know she won't be a "longbow" at 66.  I thought I was going to come in under weight, but it looks like i'm actually at the low end of where i wanted to be (low 50's) , so I may just keep her the length she is.

As far as tiller shape, i was going for circular tiller (but not full compass with the stiff handle), but was going to leave the last 6-8" stiff.  Guess i'm not really going for a true ELB after all. 

right side is the lower limb, wanted it to be a touch stiffer so it'll come around in the hand.

Thanks for the input guys.  I may put a few arrows through her and see how she feels.  Thanks for your previous input Del on the stability issues.  She's settled down pretty good i think.  In fact, I may be able to string her centerline now without offsetting the lower nock :)
Title: Re: Help with ELB lateral stability --- tiller check
Post by: PEARL DRUMS on May 09, 2013, 05:23:41 pm
Lokks good to me Kevin. Is it taking set anywhere?
Title: Re: Help with ELB lateral stability --- tiller check
Post by: k-hat on May 09, 2013, 05:55:29 pm
At about full draw and she's taken about 1.25" of set.  It looks to be full length but a little more midlimb in both limbs, which I guess tells me i shoulda gotten the inners moving sooner and loosened the outers a little more.  I may do the latter before i go any further.
Title: Re: Help with ELB lateral stability --- tiller check
Post by: k-hat on May 13, 2013, 11:44:23 am
did a little scraping and got her out to full draw.  I noticed she had picked up some moisture and after letting her dry out a bit, the weight is back up to 55+# at 28".  that gives me room to finish up (round corners, etc) and stay over 50# which was my goal.

Here she is now, lower limb (left) is left a touch stiffer on the tree so it will round out in the hand (haven't been able to get a full draw pic in hand yet):

(http://i1216.photobucket.com/albums/dd374/k-hat/100_1721.jpg) (http://s1216.photobucket.com/user/k-hat/media/100_1721.jpg.html)

let an arrow loose from across the garage into my target box and it went through the box and into the sheetrock behind.  They usually don't get that far so i'd say she spits'em pretty nicely :)
comments and critiques are welcome as always.
Title: Re: Help with ELB lateral stability --- tiller check
Post by: Del the cat on May 13, 2013, 11:58:29 am
Looks good to me :)
Del
Title: Re: Help with ELB lateral stability --- tiller check
Post by: PEARL DRUMS on May 13, 2013, 11:58:48 am
Perfect......still.
Title: Re: Help with ELB lateral stability --- tiller check
Post by: adb on May 13, 2013, 12:15:01 pm
Looks very nice. Well done.
Title: Re: Help with ELB lateral stability --- tiller check
Post by: k-hat on May 13, 2013, 12:30:37 pm
Thanks Del, PD, adb.  I'm always second-guessing myself at this point, so it's good to hear.  Can't wait to put a bunch of arras through and see how she really feels.  got some ideas I'm going to try out on the horn overlays as well, so I'll post when she's closer to finish to get your opinions.  I had given up on her as my swap bow, but it looks like she's holding promise.  ;D

Thanks again :)
Title: Re: Help with ELB lateral stability --- tiller check
Post by: Del the cat on May 13, 2013, 02:50:54 pm
...  I had given up on her as my swap bow, but it looks like she's holding promise.  ;D

Thanks again :)
It's the prodigal son effect ;D.
Sometimes the bow that you thought was going all wrong turns out to be your fave'.
Del
Title: Re: Help with ELB lateral stability --- tiller check
Post by: k-hat on May 13, 2013, 03:18:12 pm
...  I had given up on her as my swap bow, but it looks like she's holding promise.  ;D

Thanks again :)
It's the prodigal son effect ;D.
Sometimes the bow that you thought was going all wrong turns out to be your fave'.
Del

Ain't that the truf!