Hinge or whip?

[k-hat]

Hey guys, need another few pairs of eyes.  Is this still a hinge, or is it just "whippy"?  sorry for the blurry pics, all i have is my camera phone, which aint that great!

 

problem area circled:

 

This was an overly strong limb (past midlimb), think i got a little carried away trying to weaken the outer portion.   :(

Appreciate any input!

[T Folts]

It looks like a hinge to me. I think if it were whipped ended the end from the marked spot out would progessively bend, but to me they look flat (stiff). IMO

[John Lipinski]

looks like a hinge to me, too. i'd be careful with that.

[k-hat]

Thanks guys.  Yeah, been removing wood on the handle side of the hinge, think it's better, but tryn not to remove too much in another place.  Haven't had to deal with a hinge yet, how close do i get to it when shaving??  I can ID the hinge spot down to about a 1.5 inch section, do i go right up to it, or stop short?

[Art B]

Are you on the long or short string? Art

[k-hat]

The string i'm using in that pic is about a 1/2 inch shorter than the nocks.  Lays tight on the handle when strung and takes the limbs from a little reflex (unstrung) to just past straight profile.  This is the same bow from the "a little tiller help please" post.

[Roy from Pa]

I would not call it a hinge yet. Ya better stay away from it though.

[John Scifres]

Not a hinge, just need to work the other parts of the limb more.

[k-hat]

Well, i worked the rest of the limb quite a bit, put it up on the tree with the same string, looked good.  Put on the short string just to see, it had a DRAMATIC curve (seriously, almost 80 degrees) the last 8 inches of the limb.  Didn't leave it on long enough to tell if it was really hinged or just really weak the last 8 inches (or take a pic for that matter).  Giving up for the nite, will continue working the inner limb tomorrow:/   Think i've definitely learned my lesson on using the leather cup long string, and using the long string for too long!!  That's how this whole business started.  

[**DONOTDELETE**]

I understand why you guys use a long string to tiller these wood bows, but when is it best to move to the short string?  

This seems to be a good example of waiting too long and taking too much material off before going to the right sized string.

some day i need to build a few of these board bows and check this out. you guys sure seem to have fun with it.

[PEARL DRUMS]

You better not Kirk, your glass bow business will have a "For Sale" sign in the window! Its an addicting hobby that can easily suck up all your time and mind! I use a long string for about 10 minutes anymore, I get them floor tillered enough to put a long-short string on and brace the bow at about a 1/2" above the handle.

[Art B]

Couple things I would suggest Kirk. Since you make glass bows then you already have a good understanding of what it takes to produce the proper tiller. Good tapering produces good tillering. Most bowyers do it the other way around by tillering a bow to produce a taper. That's what got k-hat in trouble.

If you apply a good limb taper up front, floor tiller will be correct without ever having to bend the limbs on the floor. All that's needed now is getting both limbs bending the same. This is where a Tillering board/tree can help. In my personal opinion, one should only be used to determine if both limbs are bending evenly. No exercising the bow with the long string past intended short string brace heigth.

Then go to the short/regular string at normal brace heigth. By having a limb taper already produced, you can safely do this without fear of hinging a limb. With a limb taper already established, full draw is reached much quicker because weight reduction is about all that is needed.

Of course there's a lot more to it than that, but by using boards, limb tapers are easier to produce and tillering better understood.......Art

[k-hat]

Actually Art, that was my approach (taper -> tiller).  I roughed in the taper with band saw and rasp, then zeroed in on my lines with my fancy scissors scraper.  Best one i'd done so far.  Problem came when, yes, i did go too long on the long string due to inexperience/misunderstanding it's role(though i've tillered several bows successfully before this one), and in the beginning, one limb was noticeably stronger than the other (see other post "tiller help please").  I suspected from the beginning, removed wood from the strong limb as needed/suggested, but, as i said, got careless on the last 8 inches tryna get it to bend "a little" cause it was stiffer than i wanted.  Looking at it again, i noticed that the rings are denser on that end of the board, which explains the strength difference.  Anyhow, the rest of what you explained concerning strings/brace height/etc is the BIG lesson i've learned from this, as well as not getting careless with the scraper!  

that said, i really do appreciate the input and perspective you guys give.  I've only had two bows break on me, and that was because i was experimenting and trying to push the limits    

Kirk, i'm with Pearl.  This board-bow thing is addictive!!!  You better be careful!  True enough though, i'm looking forward to my first "real" stave bow in the near future (after i work out this learning curve;)

Question for Art:

"No exercising the bow with the long string past intended short string brace heigth."  You measuring from a string travel perspective, or how far the tips move?

[Art B]

Kevin, I go ahead and cut in my string nocks before I go to the tillering board. Using the shortest long string (double loop) possible I pull the limbs down to what would be about normal brace height (5 1/2") and lock the string down. I then run a temporary string from tip to tip through both loops. This lets me stand back and judge for even tiller. I can even take a tape measurer and check tiller off of the temporary string. Once I get the tiller even, I let it set in that position for 30-45 min. to let it lose additional weight........Art

[John Scifres]

I try to get it on the short string when it is bending well at 10" or so and feel s right.  I know that is subjective so if I had to give you numbers, it would be brace it when it feels or is measured to be 10# less than target draw weight at 10" less than target draw length.  So if you are going for 50# at 28", brace it when you are at 40# at 18".  But sneak up on it, a 2" brace height at first and then raising as you go.  My long string is almost tight nowadays.  I don't see much value in using any longer of a string.  It screws around with string angle too much when you do.

Here's a tiller-a-long I did a while back.   http://hedgerowselfbows.webs.com/fromblanktobow.htm

[k-hat]

Thanks for the extra explanation Art, that makes sense.  Sorry i'm a little thick-headed on this!    

Hey John, checked out your site with the tiller-along, it was great!!!  Most detailed tillering info i've seen, very helpful on some of the particulars, and fits with the direction i was heading with my tillering.  AND that bow is a beauty!  BTW, what did you do for the finish around the handle/inner limbs and tips?  It really sets it off.    

I'll be revisiting your tiller-along often, thanks again!!

[Art B]

Kevin, to eliminate the risk of your tips collasping on you next time, stop the limb's  belly taper where you start the side taper to the tips (for a retangular limb design). I only belly taper a limb to mid-limb and then carry that same thickness on to the tips. For example, for a retangular limb design, I would start my taper at the fade 5/8", tapered to 1/2" mid-limb and then on to 1/2" tips.

Whether you're using a retangular, pyramid or a combination of the two limb designs, 1/2" limb thickness at mid-limb will generally produce a bow of around 50# for bow lengths of 62-64".

These are rough guide lines, but will get you in the ball park for most woods.......Art

[John Scifres]

I used black dye and faded it into the center from the tips and the handle.

[George Tsoukalas]

To answer the question I long string tiller out to 10 in of string movement looking for a good bend  and I check weight repeatedly. When I get around target weight at 10 in I string the stave. That puts it at around 10 # over final target weight. Perfect. This is for a 26" draw and with a long string about 1.5 times the stave;s length. More on my site. Jawge
 http://georgeandjoni.home.comcast.net/~georgeandjoni/

[k-hat]

I wish i'd seen that belly taper concept before!!!  I thought that would've made sense, but nothing i read or saw online said it (though looking at a few bows, it looked like that to me).  It especially follows along with the tiller shape vs bow profile idea in TBB etc.  So much to learn and so many bows to make!!  

I went ahead and tried the new tillering/string advice y'all have given on a new bow for my son last nite.  It's a simple bendy bow, with tie on nocks.  It worked out really well.  Already had the taper down to profile.  Applied a short-long string that just fit, and saw quickly I had a strong limb, scraped it several times (stayed away from tips!) and got it in line with the other (left it a touch stiffer), then strung it.  It looked good, just needs some fine tuning and the tie-on nock needs to be redone (loop slipped underneath the shim), but otherwise i have high hopes for it!

I'll say it again:  thanks again for your help!