Overweight tiller best approach?

[stuckinthemud]

I, for one, would enjoy that

[Badger]

Everybody seems to think that how far the limbs are bending is what gets you the draw weight, it's the string angle that gives you the draw weight, that's why it doesn't matter that much how far the string is hanging down loose. This is not theory it is a standard practice I use on every bow and have for years. And George you said exactly the same thing I did you just go through a different process if you're stringing hanging loose 10 in, and you pulled another 10 in that's 20 in now if you pull it 5 lb heavy that gives you another 2 in and that comes out to you about 22 23 in. The only difference is it doesn't matter how loose the string is because you're not measuring anything to do with the limb bending

[George Tsoukalas]

I got this method from Jim Fetrow many years ago.

The idea is to not stress the stave as much as possible during the process.

At no time do I draw the stave, once it is strung, to full draw weight. Once the stave is strung I go to a scraper-like tool which is for me  a Swedish draw knife held almost vertically above the wood. I check tiller a lot.

I have a 26" draw. Let us assume  I want a 50 # target weight (sadly, those days are gone).

Once I get a good bend I even count the strokes of my scraper. Check tiller. Pull at short draw
length to register the removal.


I look  to get 40# at 20". Assuming 3# increase for each inch. That gives plenty of room to make weight.

I stop removing wood at 25" looking to get 53# at that draw length. By that time the stave as been drawn so many times at partial draw length that there should be no change.

Since a scraper-like tool has been used very little sanding is needed.


Some use the Hamm method. Get a good bend and pull to target weight no matter the draw length. That will work but...

Then there is finish sanding.

Stickinthe mud, thanks for asking and have fun.

Jawge

[George Tsoukalas]

Badger, I agree about the looseness of the sting. It has never been an issue for me. I never cared about getting it tight to the string.

I've made hundreds of bows using my method to ready the stave for stringing  and hundreds using Jim Fetrow's tillering style.

It has been quite a journey.

Be back later.

Jawge

[ssrhythm]

I probably jumped out of the frying pan and into the fire.  When I started (I've now built/completed 8 bows with two of those being children's bows) I don't know how slack my tillering string was, but it was obviously too slack.  As was pointed out, its the string angle that screwed me here.  However slack my string was, I was approaching and hitting a 90 degree sting angle fairly early in the process, so it was stacking and reading way high way early in the process.  I'd aim for my intended draw weight at 24" thinking that would give me plenty of room to slowly reduce weight as I approached 28" without ever exceeding my target draw weight.   Then I'd make a string, string it up, put it on the tree, and discover that I was already at my intended draw weight or a bit lower at 28" with some tiller fine-tuning still required. 

I finally figured out why it was happening, so I started getting a string on as soon as I could string it without it being so stout that the act of stringing it would over-stress the limbs.  Maybe I have been doing this too soon, because I can not seem to make a bow that will not take set.  That said, the bows are not really taking set until I start approaching 28" draws, and I am now never drawing it more than my target weight...so I'm thinking it's flaws in my tillering technique/ability.

Regardless, my original point...more specifically stated is...keep an eye on the long string angle to the limbs, because the angle absolutely WILL be greater than if the bow had it's nock to nock string on it, and the closer that angle gets to 90 degrees, the greater the difference the long string poundage will be  above the poundage you'd be drawing if the bow was strung...and the difference will increase exponentially with each additional inch pulled once that angle approaches and hits 90 degrees.

Like I said, most of y'all know this even if you aren't consciously thinking about it and you have the experience to know how to dial everything in with your specific process...but I just wanted to note this phenomenon for any newbies that might be trying to learn by reading all these threads.

[bradsmith2010]

sometimes a bow will take a bit of set at 28 inch draw,,,,a bow with little set and one dead even,, is not much difference in performance,,
if you over compensate making the bow longer or wider,, the added mass can be a wash in performance,,
shooting through a chrono is more telling than how much set the bow has,, sounds like you are going in the right direction,, as you make more bows, missing the weight wont happen that much,,

[George Tsoukalas]

I have not drawn a tillering string beyond 10" in probably 20 years.
If you are going to then you do need  to  make it pretty tight because of string angles. Jawge

[stuckinthemud]

Thank you all for your advice, it has given me the confidence in most of what I am doing but I have cut back on how far I draw the bow while tillering.  I got quite enthusiastic with the rasp and the weight loss program puts the draw weight at 50@18”, so about half of where I was. Figure I need to lose another 30lb but it’s getting there.

[Badger]

I have not drawn a tillering string beyond 10" in probably 20 years.
If you are going to then you do need  to  make it pretty tight because of string angles. Jawge

  George when you say 10" do you mean 10" plus the 10" loose string?? If so, that is 20 " draw. If you just weigh it like you would as if the bow was braced and forget all about tip movement, it makes it a lot less confusing.

[George Tsoukalas]

Badger, I pull the string down, mark it as a starting point, and measure down 10". That's it. The long string is only drawn 10". Jawge

[Badger]

George, you and I have gone around and around on this for a long time. All I can say is that if you are drawing some kind of connection between how far you are moving the string and measuring the draw weight then you are giving out very bad and wrong information. There is no connection between string movement and draw weight period. You measure the draw weight the same way you do on a braced bow, you simply look at where you are drawing it to and it makes very little difference how much slack you have in the string.

[bradsmith2010]

could someone post a video on this process,,or at least some pics,,

[George Tsoukalas]

I've only made a couple of hundred bows using that method.

This is just a method for determining  when the stave is ready for the short string...that is no more than 15# over final target weight.

That's all my method does.

Sorry you can't see that but it does work.

Jawge

[BowEd]

20" draw test after brace has been the length that I go by for knowing what it will be @ 28".For the draw weight I usually want these days I need it to be 31 to 33 pounds to get a 45 to 48 pound bow @ 28".
There can be a variance of 6" of bow length and it is still very close to the same with moderately straight limbed bows with equal reflex.
Recurves are a different story.

[George Tsoukalas]

I don't do videos.

There is info. on my site, however and in several articles I've written.

http://traditionalarchery101.com

But this not my first ballroom dance so you can be sure I've used this method on my bows to help me determine when the stave is ready to be strung..

Just trying  to help those just getting started from making the same mistakes I did.

How slack the string is not important. I've said that through out my bow making life and a couple of times above.

Jawge