Could use some direction

[Dave Bowers]

I have been working on on second bow for a bit now, taking my time, follow many directions and using the gizmo.
I think the bow is doing pretty good, but i could use some professional direction on how she's lookin.
I think there seems to be some limb twist going on, but not totally positive because there grain of the wood seems to run in two directions depending on which side of the limb i work on.

Thanks in advance for looking

 

Top limb front view
 

Bottom limb view
 

[Pat B]

Just like I said on PA! I would like to hear other opinions though.

[Dave Bowers]

Thanks Pat

[Art B]

Here's something that will cause what you're seeing. We all favor one side of the limb or the other as we're reducing weight (by scrapping/filing/sanding) and this causes one side of the limb to be thicker/thinner than the other. This causes limb twist. Now you add two limbs to the mix and you get that propeller look from end to end.

It's best to carry a slight belly radius throughout the tillering process to prevent limb twisting. Also keep your limbs marked with a pencil so you can tell how you're proceeding.

I use a Stanly caliper that I run down my limbs (keeping the upper jaw square with the back) whick leaves a burnish mark on the belly side. I try to keep that burnish mark in the center of the limb during the tillering process. Good luck.

ART B

[Pat B]

Dave, Like I said on PA and I think it warrants repeating here...think of each limb as 2 separate limbs, one stronger than the other(one side thicker than the other). Now think about bending both halves together with the same force. The weaker limb will bend farther...so will the weaker side of the limb in question. I am slightly dyslexic so trying to figure these things out in my brain is sometimes difficult for me. I read this example and it made it easier for me to understand. I hope it does for others also.

[Dave Bowers]

Thanks fellas, I am slowing working things out with the twist. I have the bottom limbs pretty much under control, but the top limbs is giving me problems. Its just doesn't want to straighten up.

I'll keep goin with my tillering and hopefully it'll get worked out?

[Pat B]

Are you exercising your limbs after each wood removal?

[Dave Bowers]

Funny you should say that Pat. I was exercising the limbs a t bit, but after these posts I started giving them a bit more attention. There not perfect, but better.

Here's the latest tiller results. I got it to a 4 inch brace height then put it on the tree in this pic. The tiller doesn't seem too bad IMO. There is a little limb set; about 1 inch. Would this be the time to back the bow or should I wait?

 

[Pat B]

Yes, now is a good time to back it if that was your plan.

[Dave Bowers]

Thanks Pat, I'll get on it. I think I am pretty close to having a workable bow. So I am gonna goto sand paper and hopefully fine tune things.
The twists are still there, I just don't have enough knowledge to remove them all the way.

[George Tsoukalas]

Looks good.    Jawge

[Pat B]

The prop twist won't hurt anything. You can do better on your next.

[2treks]

One thing I see but can't tell for sure from the pic, is that when you use a large string and tie it on with a knot you need to make sure that it pulls evenly from both sides. It looks as if you wrapped it around a time or two and this can make it hard for the string to pull "Squared-up" To the limb. If one side of the string is high and one side is low, you can then pull the limb at a twisting angle. Does this make sense?
   Your tiller looks good and I would short draw the bow about 20-30 times after each removal. this will set in your work and let the bow know that it can bend more. Good luck, Chuck

[2treks]

P.S. I agree with PatB, You can and will do better on the next one. Also, I digg it when guy's build bows in the living room. I built my first few in the kitchen with nothing but a file and scraper. COOL!

[Dave Bowers]

I ran into a bit of a problem today. I did some light sanding to clean up the tool marks. And my left limb came out with a bit of a hinge near the tip.
I am not really sure where i should looking to correct the hinge.

 

PS Thanks for the suggestion about the rope two tracks. I am gonna get a better tiller rope for my next bow.

[Dave Bowers]

Originally posted by Dave Bowers:
I ran into a bit of a problem today. I did some light sanding to clean up the tool marks. And my left limb came out with a bit of a hinge near the tip.
I am not really sure where i should looking to correct the hinge.

 

PS Thanks for the suggestion about the rope two tracks. I am gonna get a better tiller rope for my next bow.

[Pat B]

Put a pencil mark on the hinge and take a few scrapes from behind that back to the handle. You will have to weaken the other limb to match.

[Dave Bowers]

Thanks Pat that what I figured, so I went ahead and did it