Tiller help for newbie

[8Crow]

Hello All!  I've been scouring these pages for a few weeks now, but this is my first post.  I'm fairly far along on my first build--a red oak board bow from a piece of 72" Home Depot stock.  Nothing fancy, but I didn't want to spend any money on the first one, just wanted to do one and see how it went.  It's backed with 3 layers of drywall tape and Titebond III (again, just wanted to try it for little $)        

Anyhow, if the pic works...you should be looking at the strung bow.  I wanted to give my opinion so you guys can chime in on how well I'm assessing the situation.

So...a few things I've noticed.  1) the left limb seems stronger than the right 2) the right limb appears to have a bit of a hinge about 2/3 of the way out (it was a little worse but I worked up toward the fades a little bit), and 3) You can't see it from this pic, but if you look down the bow when it's strung, both limbs appear twisted--in opposite directions.  So that's what I see...  Would you guys agree?  What suggestions would you offer?  Thanks for your help!

 

Ok, here she is in all her glory...  I think that was around 25-26" and I need to get to 29-30".

 

[Stiks-n-Strings]

We'll need to see a pic of it drawn to what ever draw length you have it tillered too.

 As far as the twist you need to scrape more wood off the strong side. If I am thinking right it would be the side in the direction of the twist. Somebody will be along to straighten us both out on that.

[don s]

when your limbs are twisted in opposite directions its called propeller twist. i believe the twist will go in the direction of the weaker side though. if one side of the limb is say for example 3/8 thick and the other side is 1/4 thick. the weak side will be the 1/4 side and the limb will pull that way due to it being thinner. to reduce or eliminate twist you need to make the 3/8 side thinner. bring it to 1/4 thickness. if the twist remains (sometimes it will), leave it alone, as long as the string splits the middle of the handle you will be ok. unless the string pops off when your at full draw of course. i hope this helps. don

[Tom Leemans]

Needs to move more from the dips to mid limb. Add a pic of it unstrung too please. Just curious about the string follow.

P.S. Look up "tillering gizmo" and make you one.

[Pat B]

Congratulations on your new bow and welcome to our addiction! You have done very well for your first bow.
If you feel the thickness of both sides of each limb you will feel that one side is thicker than the other. This is a common malady for bows being built from a bench/vice set up. Generally the side closest to the bench will be the thicker side because it is generally harder to work on that side.
  Also like Tom said, Get more bending closer to the fades. The fades are the transition between the working portion of the limb and the stiff, nonworking handle.   ...and do make yourself a tillering "gizmo". I believe there is a "how to" make one in the "How To" section.

[8Crow]

Thanks guys!  I was kinda thinking it would twist toward the thinner/weaker side so I should thin down the opposite side.  I've read through the post about the tillering gizmo and have been meaning to make one just haven't gotten to it yet.

I'll try to get a pic up sometime soon showing it unstrung, but in the meantime...I've measured and I've got about 1.75" of follow on one limb and about 2" on the other.  Without knowing any better, I'm a little disappointed in that, but maybe that much follow on a board bow is normal?

Is it reasonable to think I'm going to get to 29-30" with this?  I've pulled it to 28" but it made me pretty nervous.

[don s]

you want to remember to never draw the bow past it's intended weight while tillering. every time you remove wood you need to exercise the limbs by pulling them on your tillering system at least 30 times. also there is a difference between set and string follow. for example, if your bow has lets say 2" of reflex when you start tillering and when your done it's unstrung profile now has 1" of deflex. your bow has taken a 3" set and 1" of sting follow. if you start with that same 2" of reflex and unstrung profile ends up straight. then, set is 2" and string follow is zero. also a board bow will not take set or follow just because it's a board. don

[8Crow]

Don - I think it's string follow I'm talking about.  If I lay the bow down flat on it's back, the one tip is sticking up about 1.75" and the other about 2".  It actually already had a little deflex to start with. I somehow messed up and glued the riser to the wrong side when I knew from the beginning I had an opportunity to build in some reflex.  Maybe I can get myself lined out right the next time!

[don s]

if you had a little deflex to start. lets say 1/2". then set would be 1 1/4" on one side and 1 1/2" on the other side. string follow is 1 3/4" and 2". it really is not important to your build. i am just trying to help you learn some of the things you will come across in your addiction and giving you examples. get yourself a tillering gizmo and finish up your bow. good luck and keep posting pics of your progress. don

[Walt Francis]

Ditto on the gizmo! It solves ost of the problems mentiond above.  I thought Dean's "Walky Talky" was great, but Eric truly designed and built a better "Mouse Trap".

[jamesh76]

Here is the link to the Gizmo that I was sent recently.


 http://tradgang.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=125;t=001047

 

James

[SEMO_HUNTER]

Ditto.......Gizmo........Supporter.      

Too stiff from the fade out to mid limb, work on that a bit first and check it often to be sure you don't go too far. Exercise the limbs in between tillering sessions by pulling about 30 times only to the draw that you have it pulling to at the moment. I do my limb exercising on the tillering board so I know exactly how far I'm pulling it to.

One other thing, it's easier for me to see what my limbs look like if I take a pic, then put it on my computer for closer inspection. I can also add straight lines and circles overlayed on top of the bow that will show me where the trouble areas are. That may help you too?

Example: You can see how flat the mid limb is much better now with some straight lines for your eyes to use as comparison. I highlighted the flat areas you need to work on in yellow.
This is how I try to scrutinize my own bows when I'm tillering, it really helps see the problem areas much easier. Also add another board to the bottom of the one your bow is resting on and add inch marks to it, makes it much easier to determine draw length to draw wt. Start measuring from the back of the handle down and start your inch marks at about 6" going on down to about 32"

 

[8Crow]

Thanks guys!  Probably not going to get back to it till next week, but I'll try to post pics as I finish up.