bbo tiller questions

[Mad Dog]

It's been a long time since I've posted. I'm trying to tiller out a 64" Torges style bbo. The lower limb is 1.5" shorter by design.
Should both limbs deflect the same amount at brace even though the length difference. I have a 61" string on it and have worked the limbs a few inches. I'll try to get pic on here.
 http://i1295.photobucket.com/albums/b634/rwmaddux/20140830_143613_zps8b51d8e9.jpg

[Pat B]

How does it shoot? The braced tiller looks good.

[Mad Dog]

Thanks Pat. This is a first bow for me and just got a proper string today from 3rivers. I've been slowly working the draw and watching weight, but wanted to make sure any problems get fixed before going foward. It has early draw weight and .75" set when unstrung. It still has facets and the handle is squared. I'm happy with it so far. Wanting 50-55lb @ 27-28". I think it's do-able

[Pat B]

What is the weight on her now? Your expectations are reasonable and doable.

[Mad Dog]

I had it on the tree with a long string with leather boots last week. I kept working the limbs, gradually pulling farther until I got to about 30-35lbs and stopped. I'm guessing a little over half way there. I'll try in morning with string, scale and get some more info. I also use a leather piece about 2" wide wrapped around string near nocking point area to simulate fingers drawing. As I pull, the pulley cable drifts towards the stiffer lower limb if I remember correctly. I just don't want to impart an imbalance in the limbs if I can help it. I know the lower limb should be stiffer. I guess the only way to find out is to try and catch any issues as I increase draw.

[Mad Dog]

Pat, here it is @18" 45lbs. rotated pic to put upper limb on top. Looks like I can make weight if I don't screw up. Should I be scraping lower limb little or both evenly. Also, picked up a little more set because of pic taking on board. 1.25"
 http://i1295.photobucket.com/albums/b634/rwmaddux/20140831_110340_zps15174587.jpg

[Pat B]

I'd keep tillering the way you are going. Your braced tiller looks very good.  You are working with a wood bow and not a glass bow. There is a difference in their manufacture.
 If you haven't already brace her at regular brace height, do so. Once you have her tillered out you can always lighten the upper limb a little if necessary.
 At 45#@18" you still have about 30# to loose by the time you hit 28". If the string tracks well, I'd take long scrapes off the belly to reduce the weight. If it seems to be getting too thin, start narrowing the limbs by removing wood from the sides.

[Bowjunkie]

Are you pulling the string from where it will be pulled when shot?

Is the bow symmetrical or asymmetrical in design?

Do you shoot split finger or 3 under?

If you are holding and pulling the bow as it will be done when actually shooting and the hook pulls sharply toward the bottom limb on the rope and pulley type tillering tree, then the bottom limb is stronger and will need weakened if you want the limbs balanced in strength.

Before I'd offer any specific tillering advice, I would like to see a picture of the bow with the proper length string, drawn on the tillering tree mimicking your holds on bow and string.

[Mad Dog]

Pat,in the 1st pic it was braced @5" I twisted it up to 6" and took 2nd pic on tree. I'll try for 6.5-7" brace.

Jeff, it's an Torges style. The bottom limb is 1.5" shorter than top by design, straight limbed, 64" bow. It's got a 61" string.I shoot split. When center of bow is inline with pulley, I use a doubled over 1.5" belt around string to mimic fingers and set it just below where nock would be. When pulled, the cable creeps .5" towards the lower limb.

I'll try the long even scrapes and work slowly. I've still got thickness in facets to knock down to drop weight.

Should I stay 6" away from tips? Okay to leave handle blocky until tillered?

Thanks guys for suggestions.

[Bowjunkie]

Mad Dog, instead of the center of the bow, I would align the pulley with where your string hand fulcrum(middle finger for most folks) will be on the string as you're actually shooting the bow. This fulcrum point will usually be offset from bow center by a little bit in an asymmetrical bow such as you're making... and a lot more in a symmetrical bow. Then and only then will relative limb strength reveal to you where work needs directed.

I too make my bows very similar to how Dean does... a 64" bow would have a bottom limb 1 1/2" shorter. I also shoot with a split finger release and tiller so the string fulcrum comes straight down, and the bows often result in an even tiller, or very near it. When a bow of mine pulls 1/2" away from the plumb line I have drawn on the wall to indicate perfect fulcrum travel/balanced limbs... I know I have work to do and where to do it.

My advice is to precisely locate your middle finger on your leather strap, orient it exactly on the string where it needs to be, allowing for 3/8" high nock point above the shelf, arrow nock thickness, etc, figure it all out, measure and mark on the wall, do what you gotta do to mimic how you shoot... and then align your pulley, directly below, plumb if you will, with the string hand fulcrum. Draw a plumb line on the wall to indicate perfect fulcrum travel, then give her a tug and see what she tells you. If the fulcrum drifts from the line toward the stronger limb, weaken it.

[Bowjunkie]

I should add. If when all the above is done you would like to allow a bit of extra relative stength in the bottom limb because it's shorter and under more stress per inch, you can do so by allowing the string to drift toward the bottom limb's side of the line by 1/8" or so. Try to ignore the brace height 'tiller measurements' until you're done. They should be a result of your efforts, not guide them.

[Mad Dog]

I started working before I saw your post. I ended up doing it similar to your post. I took even amounts of wood like Pat suggested. Mainly worked lower limb. Got the cable pulling within 1/8" deviation,took off 6lbs, and added 2" draw.
Now 46lb @20" got 6" to go. Looks more balanced now @ 6 1/8" brace.
Thanks again.

[Mad Dog]

Guys, scraped some more. I did what i think bowjunkie was suggesting and had where bow hand supports (under arrow pass) and where middle finger would be on string aligned with pulley. Cable tracks slightly to lower limb. It's 50lb@24", 6 1/4" brace, 1 3/16" fades to 5/8" tips, 1/2" limb thickness. Should I continue removing thickness or start narrowing limbs? Should i take more off the handle near fades to shorten the handle area or leave as is?
pics included
 http://i1295.photobucket.com/albums/b634/rwmaddux/Mobile%20Uploads/20140910_120449_zps2e001798.jpg
 http://i1295.photobucket.com/albums/b634/rwmaddux/Mobile%20Uploads/20140910_120332_zps0109adef.jpg
Thought about Pat B asking how it shot and took it out and shortdrawed (18-20") a few arrows through it.
Seems zippy, quiet and no vibration.  :D  
As always, thanks for comments.

[takefive]

Tiller looks really good to me.  I would keep taking thickness off the belly with either a fine rasp or scraper until you hit your weight while trying to keep the even tiller you have.  Do you have a Gizmo or a 6" block of wood to check the evenness in the arc that the limbs bend?