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Main Boards => PowWow => Topic started by: Coach on February 25, 2008, 02:30:00 PM

Title: tiller input needed
Post by: Coach on February 25, 2008, 02:30:00 PM
(http://i255.photobucket.com/albums/hh151/beth-bucket/tiller1.jpg)

OK--I need some input.  To me the top limb is bending too much just out of the fades and not enough in the outer third.  The bottom limb is stronger but it looks to me like the outer third needs to bend a little more.  Six inches from the top fade I have 3-sixteenths positive tiller, at 12" from the fade I have 2-sixteenths positive tiller and about that 18 inches from the fade.  It is pulling 55# at 28"  I was wanting 60# so I am a little light.  I have plenty of bow cause I wanted to make a long one.  It is 72" tip to tip and 70 inches ntn.  I do have length to shorten and gain some weight.  Darn thing is a little louder than I like when I shoot it.  I am thinking it might be tiller.  It does shoot an arrow well but I think it is too loud.  1 1/4 " fades to 1/3 limb and down to 3/8' at tip.  If I cut the tips off I will have to take off i 3/4" on each end leaving me 68 1/2" tip to tip.  Let me hear it. Coach
Title: Re: tiller input needed
Post by: John Scifres on February 25, 2008, 03:43:00 PM
Tiller is fine.  Shorten it and then retiller.  You will pic up your 5# I bet.  Nice job so far.

Make your tips as narrow as possible.  I start at 6" from the tip and make it 1/2" wide and then taper down to 3/8 at the string nocks.  You don't need much ast all past the string nocks unless you use a tip stringer.  Then, make it as small as possible.  It will quiet down when you have properly spined arrows and a leather strike plate.  String silencers help a lot too.
Title: Re: tiller input needed
Post by: Art B on February 25, 2008, 03:48:00 PM
Photo shots are really deceiving so I won't comment on what needs what but your bow bends great. It's always a good idea to show an unbraced side view to help determine it's braced profile. If that's Osage you might try heating treating (not to the degree of toasting)to raise it's weight instead of shortening. How seasoned is your wood?

Personally I don't worry to much about numbers when setting a tiller. If both limbs pull evenly at full draw then that's what you want. Most times this will end up showing a positive tiller in your upper limb but not always. To me the tiller's just right when I can put a little heel press of the lower part of the handle and feel a slightly stiffer lower limb.

Try a set of silencers and see if that helps the noise. What type of string material are you using? Would help to see a pic of the bow balanced on your finger in relationship to it's arrow pass. Do you have your string nock and arrow pass marked and holding the bow according in you pic?-ART B
Title: Re: tiller input needed
Post by: Coach on February 25, 2008, 03:53:00 PM
Thanks John, I was hoping to hear from you.  I was trying to copy the bow Jim Hamm described in The Primitive Archer and that is the reason I made this design.  I do think I will shorten it because I do want a little more weight.  Thee is a small pin knot just above mid limb on the outside of the top limb that concerns me a little.  It does not quite go all the way to the bows back which is why I did not detect it.  I am a little concerned that shortening the limbs will put even more stress on it.  The wood seems solid through it and not pithy at all.  That is the only blemish on this entire piece of osage.
Title: Re: tiller input needed
Post by: Coach on February 25, 2008, 04:15:00 PM
I could beef up the string a little.  It is only 14 strands of b 50 and it is not served yet. String nock not on yet and arrow pass is roughed in Art.
Title: Re: tiller input needed
Post by: ONE SHOT on February 25, 2008, 04:19:00 PM
Coach:

Your pictures didn't show up for Me. But if you are concerned about the pin knot in the limb you can cut out a half circle at the knot, kind of like a biscuit or half moon, take another piece of Osage and insert it into the opening with URAC-185 and that way you can salvage a bow that is on the questionable side for staying together. Just an idea to give some thought about....ONE SHOT...  :)    :)    :)
Title: Re: tiller input needed
Post by: Bert Frelink on February 25, 2008, 04:36:00 PM
Coach,
If you do not want to cut the length down to gain some weight, you can flip the tips with a heat gun and you should have no trouble gaining what you are looking for.
Regards, Bert  :scared:    :scared:    :bigsmyl:
Title: Re: tiller input needed
Post by: Eric Krewson on February 25, 2008, 05:12:00 PM
Never had a problem with a pin knot on the limb edge but have had problems after drilling out a knot and putting in a plug. My advice is to shoot that rascal, don't worry about a pin.
Title: Re: tiller input needed
Post by: Coach on February 25, 2008, 06:02:00 PM
Thanks, Eric.  I believe that is what I will do. Coach
Title: Re: tiller input needed
Post by: Jim now in Kentucky on February 25, 2008, 10:44:00 PM
Coach, I have  to disagree with just  about  everyone  but you. Your assessment of tiller is just the way it looks to me. Having said that, it may not  matter at all if it shoots well.

Finding the best spine to match the bow  may quiet it  down a lot too.
Title: Re: tiller input needed
Post by: NorthShoreLB on February 25, 2008, 10:59:00 PM
Nice bow !...all I would do is narrow down the outher limbs to give it a bit more of a whip tiller, I belive it works better on longer bows, the tiller you have now is more efficient in  the mid 60" bows.

...and belly temper it, that will get you a few pounds.

Piking is a good option to, I had a couple of bows that got quiter after I took a few inches of.

but altogether, a nice bow you got there.
Title: Re: tiller input needed
Post by: Coach on February 26, 2008, 10:15:00 AM
Thanks for your input everyone.  I love looking at things in different ways and getting ideas.  I have used the caul and heat gun on this stave to put a little reflex in it but I am curious on this belly tempering.  Is it that different than putting reflex in the bow where you use a heat gun?  What would be the process for belly tempering?  Coach
Title: Re: tiller input needed
Post by: Art B on February 26, 2008, 06:13:00 PM
Heat tempering is usually applied right after floor tillering and before the bow is drawn. This prevents removing to much of the treated section and losing it's benefit during final tillering. I think you would have gotten some benefit from tempering had you not already heated your bow on the caul. Tempering seems to benefits the low compression white woods more so then compession strong wood like Osage. But I think any benefit you might receive for tempering now depends a lot on your growth ring ratio (spring/summer). -ART B