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Main Boards => The Bowyer's Bench => Topic started by: Burnsie on October 14, 2022, 03:40:01 PM
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I've been working on my first Osage self bow for some time now - a lot of reading, YouTube vidoes...etc.
I thought I was coming along pretty nicely, but then this happened. I've got more staves, so back to the
bench.
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It had a walnut handle and tip overlays that I was pretty happy with - Kindling now - Arrrgh!
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Is that a stave or board bow? Looks like it has a drastic grain runoff.
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Is that a stave or board bow? Looks like it has a drastic grain runoff.
It was from a stave.
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Did you follow the grain lines on the back?
after you chase a ring you take your stave out side where there is a lot of light and draw a line end to end following the grain lines on the back of the stave.
(https://i.imgur.com/9uJORrl.jpg?1)
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Other than grain run out, it looks like your bow is still pretty thick and the edges are squared, that's asking for trouble..
Before tillering, all the edges should be faceted and rounded over a tad and sanded smooth to remove file marks..
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One more thing. I do not glue on tip overlays before the bow is finished. Just extra work if it should break.
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- Rounded off edges - nope. I planned to as part of the finishing process, but didn't realize it was so important during tillering.
- Follow grain on back of bow - sort of. I think I was more concerned with trying to avoid defects in the stave. (pin knots, crack along one side..etc)
Glad I put this up and asked - Thanks guys, for all the help and knowledge.
I guess this is how you learn. Got a crack a few eggs to get to the omelet.
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You are not alone, we all have had bows break on us and still do sometimes... That's how it goes making all wood bows.
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You could have 4 staves none of them may not make a recurve if the tips go left or right or knots in the wrong place
The stave will tell you what it wants to be
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Looks like more of a club than a bow :tongue: Did you purchase that stave or harvest?
I hope nobody is selling staves with what looks to be severe grain runout.
What is that large bump on the handle side of the break? It looks huge in your picture.
You should make yourself a Gizmo, it will get you a long way into the process before going to the tillering board.
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Looks like more of a club than a bow :tongue: Did you purchase that stave or harvest?
I hope nobody is selling staves with what looks to be severe grain runout.
What is that large bump on the handle side of the break? It looks huge in your picture.
You should make yourself a Gizmo, it will get you a long way into the process before going to the tillering board.
I split the staves out of half of this log.
The bump is some meat I left around a pin knot that was close to the edge.
This kind of gizmo?
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Nice log Burnsie :thumbsup: Looks like you can afford to be picky about your staves!
You might have created a extra strong spot with that large meat bulb, and that can be as bad as leaving it weak.
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Keep in mind here bro… I have very few attempts at doing self bows, and none of them were hunting weight bows. Just kids bows….
But I have a few questions if you don’t mind.
Did you do any floor tillering prior to flipping the tips and long stringing it? It looks to be pretty thick coming out of the grip area to mid limb.
What are those two gizmos on either side of your grip support on the tiller tree?
What kind of draw weight were you targeting? Kirk
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Kirk/Roy
I'm not sure you would call it true floor tillering, I did some simple bending of the limbs to get an idea
if they were flexible enough to start using the tiller board. To be honest, I'm not too sure of what the
correct floor tiller process is.
As you have probably surmised by now, I dove into this with little/no experience building a self-bow - a lot of
trial and error. I'm a decent wood worker and pretty good and coming up with my own jigs and methods to do stuff,
but this selfbow thing is more of an art.
I was shooting for a bow in the 45-50 lb range at 28". In the photo where I am pulling it on the tiller board, the scale is reading
52.1 lbs at that amount. It was obviously not close to where full draw would be. In later attempts at exercising the limbs I went 2-3 inches beyond what you see in the pic and is was at 59.5 lbs. I assumed at this point I still had a fair amount of material to take off to get to my target.
The two gizmos on either side of the handle support are some adjustable levelers to keep the bow level while pulling on it. I was having trouble with one side or the other starting out lower or higher than the other making it difficult to determine if the limbs were bending to the same line on the grid. I figured being that tight to the handle there would be little/if any bending going on in that area.
I flipped the tips once I got the bow to the point where I thought I was good to start bending it on the tiller board.
As an FYI - this bow did not follow the typical osage self bow layout formula. It was going to be a narrower, deeper core bow.
Mostly because I was trying to avoid a lot of imperfections along the back of the bow.
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I wrote this a few years ago on FB.
Watch some floor tiller on youtube and mine should make more sense.
HOW TO FLOOR TILLER My way---
Learning how to Floor tiller is the best way to go.
1 Put the tip on the ground about 12" or so in front of your right foot.
2 Hold the top limb at chest high with your left hand while you bend over a little, the rest of the limb is going under you left arm pit. Right foot forward and left foot back.
3 The grip is on the right and the back is left, shove the tip to the ground ( I use a piece of thick leather 4" square on the ground) while your right hand push the grip left, this will Simulate a string pulling from tip to tip. And you are looking down the bow watching it bend.
4 Scrape any flat spots and draw a X (don't scrap)on places it's bending to much.
5 Stay away from the fades until you get it Braced
6 Scrape and repeat step 2 and 3 over and over and over and over and over and over and over and over and over and over and over and over and over and over and over and over and over and more.
A long string (as short as possible ) for tillering on a tiller tree is the same length as the bow (my way).
7 when you get it braced if 1 limb is stronger than the other scrap the whole limb on the strong side.
Your bow can be almost finished after doing this.
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OK Max.... When do you determine its time for a long string?
Are you getting so many inches of flex?
Are you rounding over the edges a bit on the back and belly side, and keeping a somewhat rectangular shape at this point as you are floor tillering?
Kirk
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OK Max.... When do you determine its time for a long string?
Are you getting so many inches of flex?
Are you rounding over the edges a bit on the back and belly side, and keeping a somewhat rectangular shape at this point as you are floor tillering?
Kirk
I draw a line down each edge for thickness of the limbs and use a big rasp to get the thickness I want on both limbs with a crown down the center, then I round off all 4 corners (back and belly). I maintain the roundness of the corners and belly center (crown) every time I scrape for floor tiller.
Then I start my floor tiller, after I like the bends I'm getting on both limbs I brace it, my first brace is very low, like 2" ( I consider this a long string), most of the time the bends are looking good so I brace it higher 3 or 4". Now you can see what is going on with the limbs.
On a tiller tree I will only pull it down 2 to 4" and back up (don't pull it down and hold it forever, only a few seconds) I don't like a tiller stick at all.
The first time I did this floor tiller thing I was amazed how easy it was to get them bend good and my bow was finished basically, you need to shoot it once you get it tillered and come back and fine tune it again after shooting, done
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OK Max.... When do you determine its time for a long string?
Just to throw some more confusion on the fire...
I am not a great proponent of floor tillering, having zero ability to be able to tell much from the angle I get looking down the limbs. But after having done a few successful bows, you do get an idea of how it should feel and move. Since I design my bows mathematically I know very close to what the finished thickness and profile will be, so I get down close to that and then do a bit of floor tillering to make sure the tips are moving 5-6" with a reasonable looking bend and feel, then I will go to a long string and start checking it on the tree and fine tuning from there.
Mark
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I’ve seen a lot of self bowyers do their tillering before they put backing on the bow. What’s your philosophy on this procedure? It never made any sense to me personally, because the backing will most certainly increase draw weight, and throw the tiller off. I realize this doesn’t typically apply to an Osage self bow because backing is seldom needed. But I’m still curious what you think.
I’ve also read a bit on exercising the limbs to stabilize compression during the tiller process. I’d be interested in your thoughts on this too. Kirk
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I’ve seen a lot of self bowyers do their tillering before they put backing on the bow. What’s your philosophy on this procedure?
Depends on the backing. If it's snake skins or something else light it won't change the tiller much if any. The guys doing sinew bows also get them bending pretty good before adding the sinew, but that is something I have never tried so I can't say. Any time I have backed a bow it's been because I was worried about a limb failing so I have always added the backing before I bent it very far.
I’ve also read a bit on exercising the limbs to stabilize compression during the tiller process. I’d be interested in your thoughts on this too.
On wood bows exercising the limbs after every change is necessary to see what the true bend is like and to be able to accurately measure the draw weight at that point. Even on my wood lam bows I don't just pull them to full draw immediately, I work them out in stages on the tillering tree to check the bend and tweak anything if necessary.
Mark