Tillering: Thickness or a curve

[lostarrow]

It appears as though most of your bending is happening in the inner limbs.
Can you post a picture of it drawn again but with the camera square onto you.

 +1 . Looks a bit hingey on the bottom, right out of the fade as well?  Work the limbs to get  them bending more from the mid limb to the tips. Don't touch the fades. Leave the last few inches stiff at the nocks . If the draw is too light for you , you could always pike it ( shorten) a couple inches to bring the weight up. What is your draw length? 

[policetac]

Thank you very much for your compliments!

It is always nice to hear positive things about yourself, but it's even more pleasant when they come without solicitation or expectation. So again, thank you.

Yes, you caught me! That is not really a full, or my natural draw. I was looking at the pictures after I came back in and happened to notice the same thing myself. I've been trying to figure out why I might have been worried about snapping it at the time, and came up with this.

Now I know that this is probably knowledge I should have had before I even picked up a saw, much less starting to tiller, but ...?

Anyway, I found I had a few pieces of common-sense concepts missing when I started. Leaving me with a basic question that I didn't even think to ask. "How do I check to see if I can safely pull the string back all the way to where it's supposed to be?"

Doesn't get more basic than that does it? Here I am doing a specific job, using a specific tool, for a specific reason, and all I do is focus on "ONE" of the reasons for the task. Limb curve. Instead of performing the task "completely" which includes setting the draw length.

The answer to my question then becomes, "While in the tillering rack, be sure to measure the draw length as part of the process." That knowledge might go a long way in allowing me to trust my actions as they relate to the bow.

I know it seems strange to enter into a project without a firm understanding of the processes involved, but when I started I had apparently underestimated the complexity involved in some areas. Plodding ahead anyway, I must have became slightly overwhelmed and a bit impatient at times. Thus causing me to make basic mistakes.

Realizing this now, I'm going to put the bow back on the tiller and check my draw length properly. (Thank you once again!)

But..., I have one more question first. How does one know the difference, or build up trust enough to pull something seemingly on the verge of failing? I guess I don't really have a good idea of my own strength verses that of the bow. As the bow came back and became harder to pull, I wasn't able to tell the difference between the real power of the bow over my thinking that I was going to break it.

What I'm wanting is to feel like "I'M" the one that can't pull it hard enough. As if even one more inch would send it off with pure power. Exploding the target with it's energy. So I ask; "Is this something that can be, or should be felt from a bow made in a garage?" How do you know when too much is too much?

Anyway... I'm going to go ahead and check that draw length and then get outside and try it again. This time with a FULL draw!

Again, thank you for your critique, and "I'll be back!"   

[lostarrow]

During the process of tillering you are only pulling it back a little more each time between adjustments (scraping , rasp, sanding, etc. ) Then you should be exercising the limbs  to make sure they are giving in to your last request for correction. I pull it back at least 40 times after every correction or adjustment in weight.  If everything looks good, add another inch of draw . Repeat. If it suddenly becomes difficult to draw  at a given length it is getting near or pushing  the limit of the wood/ design. It's called stacking.(not good) If you set up a tillering tree with pulleys ,it becomes a lot safer ,as you are several feet away. Asa you are exercising it  ,if you hear a tic or cracking noise , stop immediately and find the source of the sound. Usually but not always ,the bow will give you fair warning. ............ sometimes it just blows! This is what is called a dramatic  failure  ,as pieces go flying and it is accompanied by a loud crack ,not unlike the report of a firearm! When your bow is finished , keep an eye on the belly for frets . this is a good indicator that the days are numbered for the bow. It may still shoot a couple hundred arrows, but it is telling you that it is receiving all of the stress in that area. The more you stress it , the more damage, the weaker it gets and the more the stress will be concentrated on that spot. big nasty cycle.  Unless the bow gets damaged , or the wood is too dry, it will give good warning. 

[policetac]

Well, it looks as if I might have been just a wee bit off!



So I have to ask.
If I'm showing 20" in the tiller at a pull that seems safe,
yet pulling closer to my true draw length of 29 1/2 when I'm shooting,
Which draw is correct?

I mean, if I can draw it to 29 1/2 in the field, how come it feels like it would be waaay too much to pull it 9 1/2 more inches in the tiller?

How does one determine the difference between pulling hard because it's close to breaking, and pulling hard because you have a strong bow?

I'm sorry if I'm asking too many questions, but some information just doesn't cut it when coming from a book. Besides, that's what these forum's are for right?

Thanks again for all the help. 

I

[Badger]

  You can't feel when the bow is about to break. It is not getting harder to pull back because the wood is bending more, it is getting harder because the string angle changes as you draw. You have to give the bow a good workout on the tiller tree using a rope and pulley at your full draw or maybe 1" past. Then you will feel confident shooting at your full draw.

[policetac]

So part of the tillering process is repeatedly stretching the bow while it is in the tiller?
As if you were breaking it in?

What exactly is meant when one is "exercising" the limbs?

How is it done?

Thank you

[Weylin]

Your confidence will come from knowledge and experience. If the wood is sound and the design is appropriate then you can make a bow out of your garage that can be safely pulled far past your physical capacity. There are people that make warbow replicas from back in the bad old days of medieval England. Some of those bows can be 150# (or more) at 32". 

[Weylin]

There are many people who exercise their bow as the tiller. that means they are confident about their tiller out to a certain weight and length, say 50# at 15". Then as they pull it to 16" they notice that there is a flat spot. They scrape on the flat spot a bit and then they put the bow back up on the tillering tree (with a pulley) and draw the bow out to 15" or so a certain number of times (lets say 30) and then they draw it out to 16" to see if the change they made has registered in the wood.

That being said not everyone does this exercising routine. I don't. Of course in the process of examining the tiller and the movement of the limbs my bow does get exercised but I don't personally think it's necessary to do it a set number of times (or any more than is necessary to assess the tiller). That was just the way I was taught by my mentors. There's more than one way to skin a cat.

[policetac]

Wow! 150# from a wooden bow?  Cool!

I understand that knowledge will come through trial and error, but until then...

I still come back to my last question? How do you know when you are pulling too hard on the bow?

I'll try another way.

What if I didn't have a scale handy and someone says to me, "Okay, now without breaking it, pull the bow back to 63 1/2 pounds or just before breaking."
How the heck am I supposed to know when that is?

Let's say I put my bow in the tiller. I then pull on it until? What? Until it's tight? Until it's bending? Until it reaches 67 1/2 pounds?

How do I know if I'm supposed to go to the next notch? Perhaps I should stop being such a baby and just pull on the darn thing.

How do I know how hard, and how far to pull this thing at each step?

I'm told to put it in the tiller, make my adjustments, then try another inch. How do I know I pulled it far enough the first time?

Am I supposed to be doing this with a scale, a measuring tape, and a scraper all at the same time? How do I know my wood can handle even "trying" to go to 30 pounds or one more inch?

See my confusion?

Thanks again
 

[Badger]

  Experience has taught us that certain demensions from certan woods can reliably expected to draw out to a certain weight and draw length. You need to get a scale and measure as you pull it further always correcting any mistakes in tiller before going further. You can rely on the demesions to give you a specific draw weight but not 100%. Learn about chasing back rings and board selection while you are hyere also. Your bow doesn't look to bad.

[lostarrow]

I exercise it to get it used to bending. If you want a piece of wood to break , you do it with a quick sudden motion ,where it will break at the weak point. ( over a knee or in the case of a bow ,at a hinge) If you want it to bend , you do it slowly and repeatedly , a little farther each time. Just my point of reference. As Weylin pointed out there's more than one path up the mountain, And he turns out some damn fine examples! A wood bow will increase in draw weight smoothly regardless of  final draw weight. A 150 lb. bow will not suddenly go from 80 to 150 in a couple of inches. you will definitely feel when it starts to stack. The heavier the bow, the more it will take to pull from brace . On something like a war  bow 100+ you should expect a gain of around 4# per inch . On a lighter hunting bow of say 50 lbs. you can expect a gain of between 2+3 lbs. / inch of draw. The smaller than expected difference between the two ,is due to the longer power stroke   ( 32" draw) of the war bow.
 
 The point I am trying to make is that 2-3 lbs. suddenly ramping up to 5 lbs. is easily detected. It feels like you are hitting a wall. You'll know.

 A scale is a huge help  ,and can be had from the local dollar store for a couple of dollars if you are on a budget. (cheaper than a bathroom scale and your wife won't be pissed at you) It is not indispensable ,however . Bows have been made for thousands of years without. Once you start using one, you'll wonder how you ever did without it.

 A bow can break at any draw weight  . The weight is not the only determining factor  . A poorly designed bow that doesn't have enough working length of limb for the draw length  will break even if it's a 15lb bow. The same piece of wood could produce a 60 lb. bow or more if you increase the limb length.
 Of course there are a lot more factors that can be changed for your requirements , but keep it simple until you get the feel for it , then you can start experimenting with  shorter, wider, recurves ( static and working) sinew backing etc. ,etc. to push the limits of what wood will do.   

[Don Case]

I think I know what you're struggling with. You pull to a point and every fiber of your body is saying, "It's going to break if I pull harder!" My advise is to pull harder. I seem to have a block at about 25#. I'm afraid to pull more because I'm sure it'll break. What I did was put another pulley in my tree to give me a mechanical advantage of 2:1. Now when I feel 25#, the bow is bending 50#. It became a non-issue. I'm sure time and more bows will fix this but I needed the extra pulley to get past this mental/physical block. You look like a pretty robust dude so I'm sure it's just a little mental thing you have to get through. Maybe you could put a F^&^*glass bow on the tree just to give yourself a feel off what it's like.
Don
Oh, one more thought. The pulleys you use have to be free running(greased) and have the largest diameter that is convenient. I would say 2 or 3 ". Otherwise you will be pulling way harder than the bow sees.
Advise from a newby, take with salt
Don

[Badger]

  Once you build a few bows the scale become less important. Unless I am doing something special I just build a bow by hand and feel. Once I have it about finished I put the scale on it for final adjustents. I am usually within about 5# which is enough room for some fine tuning.

[Don Case]

What's your definition of a "few" bows, Steve?

[Sidewinder]

I use a tillering tree with 1" marks to measure the draw. It is attached to a 100lb spring scale so I never pull it farther than the target weight and draw length I'm shooting for. Exercise it between wood removal sessions and it will reward you with less damage to belly fibers and it won't take as much set. Set is where the belly fibers have been crushed and will not store as much energy, thereby reducing the amount of energy transferred to the arrow upon release. That results in slower arrow speed.  Keep hanging around here and making shavings and asking questions and it will all come to you in time.   Danny