Upper limb twist on Ipe bow? PICS*

[PEARL DRUMS]

I am at final tiller on my Ash backed Ipe bow and I noticed my upper limb has a long, slow twist from the fade to the tips. I ran a fishing line from tip to tip and it stays right down the center. What is cause of the twist and how can I fix it? Its long and slight, but still not acceptable. I have 3-5# of draw weight I can remove if needed. Thanks

[vanillabear?]

[Pat B]

I agree with VB!

[PEARL DRUMS]

I marked out 6" increments from tip to handle and never got more than .002-.003" variance from side to side. If I am holding the handle, belly up the limb twists to my left. Should I remove wood from the right side of the limb even though the numbers are very tight already? Or is my bow firewood? I hope not, I really like the appearance so far. My antler tip overlays turned out perfectly. My lower limb is perfectly lined up. Thanks again guys

[Pat B]

How about a pic. There might not be enough twist to worry about. Is the twist visable at full draw or only at brace or both?

[PEARL DRUMS]

Pat your a Bowyers Bible in person! I can see it at 2/3 draw plus (farthest I have went so far) and at brace, but less at brace. I will try to get a decent pic tonite when I get out of work.

[Pat B]

That tells me that the limb thickness is uneven from side to side.  I don't measure the thickness but use my thumb and fore finger to feel the thickness. Way more accurate than sight. I check thickness along each side of the limb but also across the the limb.
  If you don't have one of Eric's tillering gizmo make one. It will help you find the stiff spots as you tiller. I use one and check the bend down the center and down each side of the belly as I tiller. This simple tool will show you right where the stiff spots are.

[PEARL DRUMS]

I measured the thickness from side to side and never found more than .002"-.003" variance in it? Its just short of perfect, thats why I cant figure the twist out? I have a tiller tool on my wall with a pulley and rops. My tiller actually looks pretty good at 10 feet away, its that dang twist that gets me.

[PEARL DRUMS]

I just had a thought. What about limb width not being even from both sides of center?

[NTD]

"I have a tiller tool on my wall with a pulley and rops."

This tells me that you might not know what Pat was talking about when he mentioned the tiller gizmo.  Here's the link for the tool he's talking about.

 http://tradgang.com/noncgi/ultimatebb.php?ubb=get_topic;f=125;t=001047

Yes width not being even can contribute to twist.  Pics always help though :-)

[PEARL DRUMS]

Ahhhhhhhhh! Now I know what he means. I will have to make one tonite. Pics will be on here tonite around 5 pm est, thanks for the link NTD!

[NTD]

No problem.  They really are a good tool.  It will very quickly speed up the tillering process especially on board bows. Just remember that it can't read the fades for you and for me I like the last 10" of my limbs pretty stiff so I don't use it there.  I tiller the fades and tips by eye.

[Pat B]

Thanks for posting that link, Nate.

[George Tsoukalas]

PD, I know what you mean. I made a yew bow. I was careful to remove wood evenly from both sides of the limb. After all yew does't grow on trees in NH. The stave still twisted. To fix it remove wood from the side furthest from the string when the stave is drawn. Flex a few times. Continue. Use a scraper. Jawge

[Sal]

I had this happen to me on a bamboo backed ipe bow.  It was due to uneven reduction of the bamboo backing.  The twist was as you described, gentle and from the handle to the tip.  I tried several ways to straighten it, like scraping, "shooting it in" and flipping the bow, but none worked.  Finally I just gave up and shoot it as is.  Its a great shooter, by the way.  

For some reason it likes the arrows on the side that has less clearance.  Strange, but it shoots really well.

[PEARL DRUMS]

My ash backing was planed dead flat prior to glue up, then I planed the entire glued up bow flat again. I am going to go over my limb width and thickness one more time before I throw the towel in and try shooting it as is. My only concern is the bow "flipping" on me at full draw, something tells me that would hurt?

[PEARL DRUMS]

Here is a good shot of my issue, best I can get anyway. The camera is square to the bow. You can see the right side (upper) limb twisting towards me. This at 20" draw. Please feel free to comment on anything you notice good or bad, PLEASE.
 http://i1129.photobucket.com/albums/m518/chrislovesjean/000_0048.jpg?t=1291935399

[PEARL DRUMS]

It doesnt matter now, I got some fire wood. I scaled it at 25# @ 20", so I thought I should try for 23" and see what I get. Well it pulled nice and even to 23" and 29# and blew mid limb, top and bottom. My backing seperated cleanly from my core. I used TBIII and made sure to scratch the surface's with an old hacksaw blade. I was really getting to fancy this one.......kinda stings. Osage board bow is my next shot, hickory backed. Thanks for all the help you guys gave me on his one, much obliged.

[vanillabear?]

[NTD]

Sorry it busted on you.  Scott is right about the TBIII though.  Also I had a failure with Ash backing on Ipe.  I thought I had a clean quarter sawn piece but after the failure I was closely inspecting the ash and found very very small pin knots where it had failed.  

Good luck on your next project.

Nate