Author Topic: Tillering Advice  (Read 5360 times)

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Offline Wooden Spring

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Tillering Advice
« on: January 21, 2013, 04:24:19 pm »
What I've got so far... I've got a hickory flatbow all roughed out and backed with linen. It's 69" NTN, 11/16" thick at the tapers, then tapers down to 3/8" at the nocks, it's 1-1/2" wide for 12", then tapers down to 3/8" at the nocks. It's got a 4" long handle, and 1-1/2" long fades...

Here's my problem... I've only tillered it to just a couple inches beyond brace height, (shown in the picture with the long tillering string) and it pulls 60 pounds to get it that far. Now, being a newbie to the whole process, what's the best way to bring the weight DOWN? Do I take wood off of the sides? Do I take wood off of the thickness? Or some combination of both? (I want the final weight at 28" draw to be around 45-50#)

"Everything that moves shall be food for you..." Genesis 9:3

Offline ionicmuffin

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Re: Tillering Advice
« Reply #1 on: January 21, 2013, 04:27:58 pm »
remove wood from the thickness, continue to thin it until you have lightened it. Just remove wood evenly until you can pull it close to your draw length at draw weight on long string, then when you brace it you can fix any errors, but try to do that as best you can while removing wood. hopefully you wont have to do much correcting of tiller when you brace it.
Amo innectis arcus- I love crafting bows (latin)

Offline PEARL DRUMS

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Re: Tillering Advice
« Reply #2 on: January 21, 2013, 04:32:32 pm »
You need to low brace the bow 3-4" now and then have another look. When you start pulling in and down it changes everything.  Your fades are VERY short and abrupt, hope they dont come back and bite you later.
« Last Edit: January 21, 2013, 04:38:33 pm by PEARL DRUMS »
Only when the last tree has died and the last river has been poisoned and the last fish has been caught will we realize we cannot eat money.

Offline danny f

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Re: Tillering Advice
« Reply #3 on: January 21, 2013, 05:12:17 pm »
also  you shouldn't  draw it past your target weight or you will get some set.

Offline bow101

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Re: Tillering Advice
« Reply #4 on: January 21, 2013, 05:20:20 pm »
also  you shouldn't  draw it past your target weight or you will get some set.

That seems to be a very broad term. "target weight" Why because what if you suddenly change your mind and want 60# instead of 50#..... So now you pull a little further not knowing that you have actually pulled to much say to 58# and the bow has taken on a lot of set or more set than what was anticipated..
This is where most Newbies get into trouble. Not so much the draw weight, because I never check untill I'm 96% done. It's more of the bending factor.
Oh it's bending OK but extremely stiff like it's .........Stacking....?
"The privilege of a lifetime is being who you are."  Joseph Campbell

Offline Wooden Spring

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Re: Tillering Advice
« Reply #5 on: January 21, 2013, 05:20:47 pm »
also  you shouldn't  draw it past your target weight or you will get some set.

Well rats... Another one for the burn barrel. That's it. I give up. I've been trying to get a shootable bow now for over 6 months. I have been a woodworker all my life, and I have never had something cause as much grief as this... All those people who made a shootable bow their first try must have had some magical combination of luck and opportunity...
"Everything that moves shall be food for you..." Genesis 9:3

Offline PEARL DRUMS

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Re: Tillering Advice
« Reply #6 on: January 21, 2013, 05:24:45 pm »
Your bow is far from junk. Shorten the string up and brcae it at 3-4". Pulling it past your target weight isnt too big of deal providing the tiller is close. Hardly anything any of us would notice at the end when we are shooting. I dont even scale my bows until Im braced up at 4-5", then worry about settling it in where I want it.
Only when the last tree has died and the last river has been poisoned and the last fish has been caught will we realize we cannot eat money.

Offline PEARL DRUMS

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Re: Tillering Advice
« Reply #7 on: January 21, 2013, 05:54:16 pm »
For the record I have years and years of woodworking experience as well, none of it translates to bowyering. You may have a leg up in getting a good finish on a bow though.
Only when the last tree has died and the last river has been poisoned and the last fish has been caught will we realize we cannot eat money.

Offline Del the cat

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Re: Tillering Advice
« Reply #8 on: January 21, 2013, 06:11:08 pm »
also  you shouldn't  draw it past your target weight or you will get some set.

Well rats... Another one for the burn barrel. That's it. I give up. I've been trying to get a shootable bow now for over 6 months. I have been a woodworker all my life, and I have never had something cause as much grief as this... All those people who made a shootable bow their first try must have had some magical combination of luck and opportunity...
Pull yourself together man and get a grip!
You are 80% there!
Get a taut string on it and decide on your target weight.
Pull it back to that weight and look at the curve of it.
If the tips are coming back about 7"  and the curve is reasonable, get it to a low brace height (say 4-5") The draw weigh is always less with a shorter string. (Due to the geometry)
You are now at the very point where you must SLOW DOWN !
Don't start getting frustrated and taking off tons of wood. Enjoy slowly taking off small even amounts of wood so each time you pull it back it comes a little further... a bit like courtin'  ;D >:D O:) ::)
If you are really stressed out, have a break, make a bow out of a scrap of grren wood or have cup of tea and a bit of toast.
Come on old chap, stiff upper lip... we're not going to let a silly bit of wood wood beat us now are we ;)
A lot of it is patience perseverence and confidence. I still get a crisis of confidence now and then, and as I wind it back on the tiller I'm saying 'BANG' to myself so it won't be a shock if it explodes. Then it's a huge flood of relief when it makes it to draw weight.
Del
BTW Tiller is looking good at the moment, get it on a short string pulling back to 50# and post another pic.
Get a grip!
If I have to come over there... there'll be trouble ;)
« Last Edit: January 21, 2013, 06:40:18 pm by Del the cat »
Health warning, these posts may contain traces of nut.

Offline hedgeapple

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Re: Tillering Advice
« Reply #9 on: January 21, 2013, 06:23:28 pm »
First:  DON'T DRAW IT PASS YOUR TARGET WEIGHT!
Second: If you're at 11/16 at the fade NOW, you should have plenty of wood left to remove to gradually, taper out pass the fades by an inch.  So, you shouldn't have a problem of the bow hinging out of the handle/fade area.  The key is a GRADUAL taper from the handle to an inch past the fades.  Don't touch this area for a bit.  You can alway come back to this spot if you see it is too stiff.
Third shorten your long string so it's so tight against the belly that you have to force the bow into the tillering tree

My method: scrape the bow correcting the tiller as you go until the tips are bending about 6 inches.  Then go to a low brace of 2 to 3 inches.  DON'T PULL THE BOW PASSS YOUR TARGET WEIGHT.  When the tips are bending about 8 inches go to full brace.  Keep tillering until you reach your target draw length just DON'T PULL THE BOW PASSS YOUR TARGET WEIGHT.

Your tiller looks pretty good.  I think that hickory with make a bow still.  Keep at it.
« Last Edit: January 21, 2013, 06:38:40 pm by hedgeapple »
Dave   Richmond, KY
26" draw

Offline Del the cat

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Re: Tillering Advice
« Reply #10 on: January 21, 2013, 06:35:30 pm »
Sorry, I can't help writing some more as I'm determined to maximise your chance of making a bow.
To answer your basic question, you will have to remove wood off the belly to bring the weight down.
By this stage you should be using a fine rasp, b'stard file and scrapers.
Ok you are a woodworker, but this is a different discipline as you are asking the wood to do something entirely different, you don't want sharp crisp edges anymore.
Keep checking the back of the bow for any signs of lifting grain and round of the edges to about the curve of a 6" nail or even softer.
Take the advice offered about being carefull at the fades (it's easy to create an accidental thin point there) and if you take off an even thickness along the the whole belly it will automatically have more effect in the outer 2/3 (which is what has been suggested). That is because say 0.01" of an inch off at the tip is a greater % of the total thickness than 0.01" at the fade.
Take it slow and steady, after each go with the rasp/file etc exercise the bow by flexing it a dozen times or so and check how it looks. Always do it, never do a bit and then do some more without exercising and getting it back on the tiller.
You should get thoroughly sick of putting the string on and getting it up on that tiller! Also always put it up the same way round so you don't work on the wrong limb. (I always have top limb to the right)
Mark any bits that don't seem to be bending enough with a cross hatch pencil mark or squiggle, and any areas that look like they may be bending too much mark with L for 'leave'.
Use you fingers as well as your eyes, run the limb between finger and thumb feeling for dips and high spots. If you want the 'security blanket' of the verniers then check thickness every 6" or 4"...
If you want a bit of safety factor aim for 45# at 26 initially, then shoot it in a bit, spend some time studying it and finally tease it back the last couple of inches.
Sorry if I'm going on a bit, but we all want to see you get there.
Del
« Last Edit: January 21, 2013, 06:38:50 pm by Del the cat »
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Offline dwardo

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Re: Tillering Advice
« Reply #11 on: January 21, 2013, 06:55:29 pm »
When you take that string on and off again a million times as Dell says its important to check the profile of the bow unstrung. If the bow starts to look different in one area only then that area might be taking too much strain/set.

The fades there need to mellow a little if you can.

You will have a bow yet.

Offline bow101

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Re: Tillering Advice
« Reply #12 on: January 21, 2013, 07:09:13 pm »
also  you shouldn't  draw it past your target weight or you will get some set.

Well rats... Another one for the burn barrel. That's it. I give up. I've been trying to get a shootable bow now for over 6 months. I have been a woodworker all my life, and I have never had something cause as much grief as this... All those people who made a shootable bow their first try must have had some magical combination of luck and opportunity...

I hear ya about the woodworking part all your life. Like the others say don't give up. Like yourself I have done my fair share of woodworking and construction. It was getting me down to, but I have learned from every bow I tried to build.
  Like Dell said......"Enjoy slowly taking off small even amounts of wood so each time you pull it back it comes a little further... a bit like courtin'   

"The privilege of a lifetime is being who you are."  Joseph Campbell

Offline adb

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Re: Tillering Advice
« Reply #13 on: January 21, 2013, 07:14:43 pm »
First off, get rid of that tillering stick, and make yourself a pulley system with an in line scale. Don't leave your bow statically drawn for more than a few seconds. You need to know where you are with draw weight all the time.
 
Second, round off the edges on the back of the bow. You should do this BEFORE you start tillering.

Third, move to a short string asap. As soon as you can low brace the bow at 3"-4", do it.

Your tiller looks fine so far. Keep going. There's definitely a bow there if you're patient. Keep removing wood, using scraper and rasp, and watch for hinges.

Offline Zion

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Re: Tillering Advice
« Reply #14 on: January 21, 2013, 08:20:53 pm »
Dont give up on it dude! Making bows isn't super easy. your doing a great job on it anyway. low brace it, continue tillering from there and your done. Its really rare that anyone makes a perfet bow the first time. Even if it breaks after shooting it for a bit, it's still a learning experience and makes your next ones that much easier.
The secret of life is learning to make your own luck.