Primitive Archer

Main Discussion Area => Bows => Topic started by: mwosborn on January 11, 2014, 12:50:04 pm

Title: Tillering strategy?
Post by: mwosborn on January 11, 2014, 12:50:04 pm
Working on this piece of osage and I could use a little advice.  Have not tillered one like this yet.  Stave was a bit curvy with some reflex and deflex found in it.  How would you tackle the right limb.  Thanks!

First picture is the stave.

Second picture is after roughing out - before straightening.

Third picture is after straightening  (dry heat 2 sessions) and floor tiller.

Title: Re: Tillering strategy?
Post by: Bryce on January 11, 2014, 01:16:55 pm
Take wood off until they bend evenly(<- relative term.) and be mindful of the natural shape of the stave. ;)
Title: Re: Tillering strategy?
Post by: mwosborn on January 11, 2014, 01:50:47 pm
Thanks Bryce - it the "relative" term part I am asking about :o.  The bows I have made so far have had limbs with mostly the same or very similar profile.  As I tillered I could see and feel if the limbs where bending evenly.  Not sure I am going to be able to "see" on this one.  Kinda want to know if the right limb will remain "flat looking" in that reflex area even when the limbs are bending evenly.
Title: Re: Tillering strategy?
Post by: Bryce on January 11, 2014, 05:50:50 pm
Okay! I see what your asking!
I've painted the wall behind my tillering set up with chalkboards paint now if I find that a stave has some ups and downs and what not I'll simply take some chalk and outline the original shape of the stave to accurately measure the amount of travel for each limb.
(http://i1251.photobucket.com/albums/hh544/bryceott/DDEA7C19-1FF3-4A0C-BC63-8CFCA3C47B67.jpg) (http://s1251.photobucket.com/user/bryceott/media/DDEA7C19-1FF3-4A0C-BC63-8CFCA3C47B67.jpg.html)




I've seen ppl draw a line on the side if the limb, but to me that seems like a good way to induce excess set. Sense the limb needs to first be bent to the problem then held there while measuring the bend with a straight edge. And sometimes that method isn't always an option.



I hope that helps. Now go bend that stick!
Title: Re: Tillering strategy?
Post by: mwosborn on January 11, 2014, 11:39:06 pm
Thanks!  I like the idea of being able to draw the original profile behind the tree.  Might try to rig something up.  Oh I am going to bend it - for better or worse she is getting bent!
Title: Re: Tillering strategy?
Post by: Weylin on January 12, 2014, 03:34:42 am
On staves like that you have to put more faith in the thickness taper and less in how it looks. Use your fingers and feel the taper. You can notice even slight changes and find thick and thin spots. If the taper is spot on the tiller likely will be as well. I also use the method of drawing a straight line along the side of the limb and then holding a straight edge to the line to measure the deflection once it's braced. Like bryce said, this doesn't work with every stave (you can't get a straight line on some limbs!) and you have to be pretty close with the taper/tiller to get it braced without causing set or a hinge. But it has worked for me on many difficult profiles.
Title: Re: Tillering strategy?
Post by: Bryce on January 12, 2014, 03:56:12 am
On staves like that you have to put more faith in the thickness taper and less in how it looks. Use your fingers and feel the taper. You can notice even slight changes and find thick and thin spots. If the taper is spot on the tiller likely will be as well.

Bingo! You can pretty much tiller a bow almost completely that way.
Title: Re: Tillering strategy?
Post by: mwosborn on January 12, 2014, 10:19:01 am
Thanks guys - that helps!  1:00 am in the morning?  You guys are crazy!
Title: Re: Tillering strategy?
Post by: Carson (CMB) on January 12, 2014, 11:33:45 am
Like Bryce and Weylin said. 

Once you have it braced, try to do a lot of work drawing the bow by hand.  Be sure to pull the string with your fingers at a realistic nock point.  Feel for balance between the limbs as you work it back.  If you have a big mirror or bowyer friends handy you can complete tillering in hand. 
Title: Re: Tillering strategy?
Post by: aaron on January 12, 2014, 10:28:39 pm
1. I agree that you can (almost) tiller a bow by careful measurement of thickness taper- I do this with VM bows to get them at least to brace with good tiller.
2. Bryce- can you tell us more about the bow you pictured? did you heat deflex the handle of an over reflexed stave like carson has done?
Title: Re: Tillering strategy?
Post by: mwosborn on January 12, 2014, 10:46:00 pm
Thanks aaron!

The bow Bryce posted looks to be laminated - I am guessing the profile was glued in.?
Title: Re: Tillering strategy?
Post by: Bryce on January 12, 2014, 10:51:41 pm
Yes. It's a boo backed osage.
Title: Re: Tillering strategy?
Post by: mwosborn on January 13, 2014, 12:07:25 am
I nice looking profile I might add.   :laugh:
Title: Re: Tillering strategy?
Post by: Pappy on January 13, 2014, 08:16:25 am
You ask for strategy,so mine would be to straighten it out with a heat gun,then tiller. ;) If not the other Ideas are all good ones. :) Some like to use what they have,I like to make it what I want it to be. :)
  Pappy
Title: Re: Tillering strategy?
Post by: Slackbunny on January 13, 2014, 09:56:17 am
You ask for strategy,so mine would be to straighten it out with a heat gun,then tiller. ;) If not the other Ideas are all good ones. :) Some like to use what they have,I like to make it what I want it to be. :)
  Pappy

I tend to agree with this school of thought. Why work around it when you can change it to something better? To each his own though.
Title: Re: Tillering strategy?
Post by: George Tsoukalas on January 13, 2014, 12:04:38 pm
I'll heat to get the string on the handle or 2 remove deflex from a limb(s).
Why don't I break out the heat gun at every opportunity?
That's a good question.
I guess I like to take the path of least resistance.
I like to look at the character of a bow. Each of my bows is unique.
My bows please me.
I have no problem with how y'all want to make your bows.
It's all good.
Jawge
Title: Re: Tillering strategy?
Post by: Pappy on January 13, 2014, 12:21:04 pm
Well said Jawges,lots of options in wood bow making that is for sure. :)
 Pappy
Title: Re: Tillering strategy?
Post by: George Tsoukalas on January 13, 2014, 02:12:31 pm
Thanks, Pappy! What a great pastime we have! Jawge
Title: Re: Tillering strategy?
Post by: munkinstein on January 13, 2014, 02:38:42 pm
This might be a little out of context but when I first started out, and by all means I'm still a novice at this art, I got some cheap wood and deliberately made the bows in a fashion that would cause exaggerated hinges and other things that would constitute bad tillering.  I found at the beginning I was not seeing certain aspects such as were the wood was bending and not bending, I wasn't seeing obvious hinges, and twists.  I do now.  I just used some cheap pine that was laying around and made a whole bunch of firewood bows.  It has helped a lot with my tillering.  My reasoning is that we are very use to seeing bows with great tiller here and on other sites, but we very rarely see examples of poor tiller in bows.  By deliberately making mistakes I found how what these issues look like, how they occur and what not to do if I want to tiller a bow correctly.
Title: Re: Tillering strategy?
Post by: mwosborn on January 13, 2014, 08:44:20 pm
Thanks Jawge and Pappy for you thoughts - appreciate it.

Before I posted I figured I had 3 options...but didn't want to say anything until I got some input........1) leave it as it is and tiller it out.  2) Take the reflex out of the one limb.  3) add reflex to the other limb.

I have already heated the crap out of it to get it "straight" and the string running through the handle -- so I was reluctant to do more heating not knowing how much it can take before affecting the integrity of the wood.

Would heating again affect the wood in a negative way?  If not, would it be better to take away the reflex from the one limb or try to add reflex to the other limb.  My instinct (which may not mean much) says that heat induced reflex won't match up to natural reflex.

Thanks again,

Mitch
Title: Re: Tillering strategy?
Post by: SLIMBOB on January 13, 2014, 09:15:42 pm
I will on most of my bows heat bend in reflex in one limb to match the other (pappy alluded to this and I agree). If one session won't get it, do another. I prefer to limit the heat bending on the working parts of the limbs to only once, but I want them to match each other and line the string up down the handle. Sometimes it takes me several attempts to get it right. When I started this madness I rarely heat bent anything other than tips and handles. I just stuck with what I had on symmetry or the lack thereof. I now do my best to get the limbs to match up from the get-go. No ill effects that I can see from it.