Author Topic: Tillering troubles (Read 716 times)

ryguy24000 · « **on:** November 13, 2011, 05:41:00 PM »

I am having trouble tillering a one piece recurve. the limb tips twist to one side while drawing. Now the wood core grain also runs in the same direction as the twist. I have tried removing material from the strong side of the limb to no avail. I have removed (IMO) a lot of material. Do you think the core wood grain is effecting this?
I'll try to add some pictures to show the core wood grain

ryguy24000 · « **Reply #1 on:** November 13, 2011, 06:07:00 PM »

Here is a link to some pictures.
https://picasaweb.google.com/108920648114912707174/Ghost0002?authuser=0&authkey=Gv1sRgCNWHmc--x4iVQA&feat=directlink

LittleBen · « **Reply #2 on:** November 13, 2011, 09:26:00 PM »

In a fiberglass laminated bow the core provides very little resistance to bending. Its essentially zero compared to thd glass. Doubt if could be the core.

hunterr · « **Reply #3 on:** November 14, 2011, 03:20:00 AM »

I would also look at the noches as well as what you are taking off the strong side. The tillering is sanding glass off the back and belly of the limb.

Mike Most · « **Reply #4 on:** November 14, 2011, 09:33:00 AM »

When the bow is strung does the string run thru the center of the handle? and are both limb tips twisting to the same side?

It difficult to see from your pictures.

ryguy24000 · « **Reply #5 on:** November 14, 2011, 11:58:00 AM »

When Strung everything looks good. the limbs do twist in the same direction. The same direction as the wood grain. I stopped trying to tiller and checked my string grooves and one on the lower limb seemed a little deeper than the other so I filed the other down a little and that seemed to help.

ryguy24000 · « **Reply #6 on:** November 14, 2011, 09:22:00 PM »

My bow has an aggresive curve and I am wondering if I should have used ULS Bo-Tuff E-Glass instead of UL Bo-Tuff E Glass for lateral stability? Any thoughts?

Mike Most · « **Reply #7 on:** November 15, 2011, 05:09:00 PM »

Just to eliminate it how thick was your stack at the fades?

Might try putting an 18 inch tiller stick between the belly of the bow and the string, (kinda of a half draw) and take a pic so we could see how much they limbs are moving out of line.

What is the draw weight of the bow?

ryguy24000 · « **Reply #8 on:** November 15, 2011, 06:36:00 PM »

Ok will do. I estimate the weight around 50 lbs+-
I can tell you they move to the point that the string almost comes off.

Mike Most · « **Reply #9 on:** November 21, 2011, 09:16:00 AM »

Wondering how your bow is coming along?

ryguy24000 · « **Reply #10 on:** November 21, 2011, 11:38:00 AM »

I have been very busy and haven't had time to work on it. I will post pictures as some results of the limb twist soon. thank you.

ryguy24000 · « **Reply #11 on:** January 10, 2012, 08:37:00 PM »

https://lh6.googleusercontent.com/-TGVdyTRPgWg/TwziIGrtaQI/AAAAAAAAAAo/icbz6U_ui8s/s640/twist3.jpg

Ok I have time now and added some pictures and hope this helps. I removed material from the side opposite of the twist and it's not getting better. I wonder If the string groves are a problem? Maybe I am not understanding how the string groves effect limb twist?

psychmonky · « **Reply #12 on:** January 11, 2012, 05:42:00 PM »

I thought it twisted when you drew it....that pic makes it look like its twisted while unstrung.

Scott

ryguy24000 · « **Reply #13 on:** January 11, 2012, 09:05:00 PM »

I have it on a tiller stick with about a 14 inch draw.

psychmonky · « **Reply #14 on:** January 11, 2012, 09:24:00 PM »

String grooves affect limb twist if they aren't cut in such a way that the string is aligned through the center of the handle.

For example, if both the string nocks are cut so that the string is 1/4" right of center, and you make sure the handle stays rigid when you draw, the limbs will twist substantially because they are centered but the string isn't.

Someone else can probably do a better job of explaining.

Scott

psychmonky · « **Reply #15 on:** January 11, 2012, 09:28:00 PM »

Looking at the big picture, I think you need to close the door to your washer. The excess moisture is warping the bow. Note that its bending that direction

Scott

Bow-n-Head · « **Reply #16 on:** January 12, 2012, 09:56:00 AM »

Ryan; Lay the un-strung boe on a flat surface. Are the centers of the limb tips the same distance from the surface to the center of the limb tips? If they are, you should be able to make adjustment by deepening the string groves. IF NOT, You may have to use heat (hair dryer) to twist the limbs into alignment. Be carefull with the heat (not too hot). Go slowly. You may have to repeat a few times. Good Luck. Ray

ryguy24000 · « **Reply #17 on:** January 12, 2012, 07:29:00 PM »

Yep I'm way out of alignment! With the bow flat the bottom limb is twisting and is 1 1/16" dead center while the top is dead center at 7/8" . wow. that seems extreme! I don't know how I did that? what to do now?

psychmonky · « **Reply #18 on:** January 12, 2012, 08:09:00 PM »

Its odd that both limbs twist the same way. When you clamped it together did you alternate which side you were putting the clamps on? Or were they all on the same side? Just trying to figure it out.

Scott

Bow-n-Head · « **Reply #19 on:** January 12, 2012, 09:21:00 PM »

Ryan; Sounds like the bottom limb is OK. The measurement should be 1/2 the width of the limb at the widest width of the riser. If your riser block was 1 3/4" then the 7/8" from the middle of the tip to the flat surface is right on. Only thing that I can think of that u can do is to try heating the top limb & twist it to center. What U possibly did was U mis-drew your center line or else deviated from it when sawing out the to limb. Twisting the tip over by 3/16" should be possible. (I think) Good Luck. Ray

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