Author Topic: tiller help  (Read 492 times)

Offline gringol

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tiller help
« on: December 09, 2011, 12:10:00 PM »
I could use an experienced eye for tillering my first sinew backed bow.  It looks close to me, but I've only done this a couple of times, and both of the previous bows broke (unbacked).

 

Offline soopernate

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Re: tiller help
« Reply #1 on: December 09, 2011, 12:13:00 PM »
I admittedly am not good at this sort of thing but it looks to me like you are about ready to put a shorter string on that baby and finish her out.
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Offline PEARL DRUMS

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Re: tiller help
« Reply #2 on: December 09, 2011, 12:33:00 PM »
Put a short string on it now and have another look. Its going to change a bunch from what you see now. Your tiller is good enough that a short brace wont hurt a thing.

Offline dmikeyj

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Re: tiller help
« Reply #3 on: December 09, 2011, 12:38:00 PM »
Looks a bit stiff on the right limb, a few inches out from the fade all the way to 2/3rds out could be scraped to match the left limb.  I'd go slow with a scraper or knife blade as from here on, a little removal makes big changes.

Do you have the tillering gizmo?  You could use it in this case by setting the pencil height at the left limb, then move it to the right and see where it marks.  That'd be where you want to do the removal.

 http://tradgang.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=125;t=001047#000000

The left limb looks pretty nice to me.  You are not far from done, by the looks of it.  
I'd get a short string on it first though, like Nate says.  In fact, get it on a short string first, as the look of the tiller will be different than when on the long string.  

Luke, whereabouts in FL are you?

Mike

P.S.  If some of the more experienced guys pop on here with advice differing from mine, I'd go with what they say, as I am still a bit of a newbie myself.  Hope this helps.
Imagination will often carry us to worlds that never were. But without it we go nowhere.
I love fools' experiments. I am always making them.

Offline soopernate

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Re: tiller help
« Reply #4 on: December 09, 2011, 12:44:00 PM »
Tillering gizmo...good call buddy.
I humbly follow in the learned footsteps of those who precede me.

Offline gringol

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Re: tiller help
« Reply #5 on: December 09, 2011, 12:53:00 PM »
Mike,
I'm in Tampa, and I don't have a tillering gizmo.  I've been using my untrained and untuned eye and a cabinet scraper.

Now that you pointed in out, I see the stiff spot on the right limb.

To clarify, by shortening the string to you mean using the tillering tree with a shorter string or actually stringing the bow?

Offline soopernate

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Re: tiller help
« Reply #6 on: December 09, 2011, 12:59:00 PM »
String the bow at a low brace (two inches or so) It will show different limb movement than the long string and will give you a truer idea of what tiller profile is looking like. A tillering gizmo is easy to make with a pencil, nut, and four to six inch piece of wood.  Do a quick search...I believe Eric Krewson posted pics somewhere.
I humbly follow in the learned footsteps of those who precede me.

Offline gringol

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Re: tiller help
« Reply #7 on: December 09, 2011, 01:35:00 PM »
Ok, now things are getting a little complicated.  Here's the bow strung at a lowish brace height, and now the left limb looks a little strong to me.

 http://i1200.photobucket.com/albums/bb336/gringol/IMAG0018.jpg

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Online Roy from Pa

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Re: tiller help
« Reply #8 on: December 09, 2011, 01:57:00 PM »
Those extra long tillering strings lie. I cut my string grooves in and start tillering with a string that just reaches the string grooves.

Offline PEARL DRUMS

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Re: tiller help
« Reply #9 on: December 09, 2011, 02:11:00 PM »
Its looks fine right now. Pull it to your intended weight and let see what she looks like.

Offline dmikeyj

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Re: tiller help
« Reply #10 on: December 09, 2011, 02:20:00 PM »


Click it to embiggen.

The left limb still looks good, the right one is stiff in the outer half.  To match the left, looks like some scraping right about the halfway point out to the 2/3rd mark.  I would not try to match the ellipse with your tips, but would leave the last 1/3rd alone while trying to get closer to the line in the middle.

I would also make a new string just a bit longer than that one, depending on how far through the tillering process you are.  Something like what Roy said, just the length from nock to nock.  That brace height looks close to final brace height.
Imagination will often carry us to worlds that never were. But without it we go nowhere.
I love fools' experiments. I am always making them.

Offline dmikeyj

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Re: tiller help
« Reply #11 on: December 09, 2011, 02:23:00 PM »
Oops, I keep stepping on Pearl's posts.

Also, you are going to want to go into photobucket and set it up for no more than 640 pixel width for your pics, or do like I do with the clickable thumbnail.

And, the link I posted above is a how to for making a tillering gizmo.

Mike
Imagination will often carry us to worlds that never were. But without it we go nowhere.
I love fools' experiments. I am always making them.

Offline gringol

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Re: tiller help
« Reply #12 on: December 09, 2011, 03:31:00 PM »
thanks for the input.  The draw is going to be way light.  Probably around 30lbs.  If I shorten the bow can I bring the draw weight up a little without reducing the draw length too much?  The bow is currently 57" NTN and my draw I'd like a draw of around 26-27"

Offline PEARL DRUMS

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Re: tiller help
« Reply #13 on: December 09, 2011, 03:40:00 PM »
Rasp the handle off and make it a bendy handle bow. Snip 1" off each end and you will get a heavier bow.

Offline gringol

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Re: tiller help
« Reply #14 on: December 10, 2011, 02:36:00 PM »
Here's the latest tiller pics.  I think some of the difficulty comes from more set in the left limb than the right.  The left has ~1.5" of set while the right has ~0.25"

Pearl,
I don't think a working handle will work.  There's a pretty large knot in the handle; it came from a pretty marginal stave...I think I'll give it to my buddy's kid.

 
 
 
 
 

Offline PEARL DRUMS

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Re: tiller help
« Reply #15 on: December 10, 2011, 04:05:00 PM »
Your left limb is quite flat half way, thats why she is tilting in your cradle.

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