Primitive Archer
Main Discussion Area => Bows => Topic started by: stuckinthemud on October 10, 2022, 06:06:31 pm
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Ok, so I am tillering a yew hunting bow. I’m going for an arc of circle bend through handle round belly/fat galleon design. The tips are both twisted for the last 3” but the bow itself has no twist. It’s 64” ttt with a bit of character but not as much as I usually deal with so I find myself with a bow that has a sweet bend but is double the target draw weight. It is 80lb at 16”, but I am aiming for 60@29. When you are in this situation, what approach do you find works best?
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If it looks good, just good even strokes off both limbs, a little at a time , checking as I go, and don't get in a hurry, things can happen pretty quick sometimes, I love it when all looks good and just need to remove weight,that's a good spot to be in. :)
Pappy
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What Pappy said for sure.
I don't have a lot of experience with yew though I have made a few yew bows.
Your stave is about 62" and not pristine.
I am wondering if drawing it 29" even if it bends in the handle might be a reach.
Perhaps a rawhide backing would help?
Jawge
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same,, I just remove wood slowly and keep the tiller even as possible,,no need to draw it to 80,, if you aiming for 60..
its about 60 at 12,,,
some even suggest not stringing it to you get a bit closer to target weight,, estimating the draw wieght with long string,,
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Like others have said here I would do even scrapes till you get closer to your draw target. I make it a point not to ever surpass my draw weight during tiller. I also stop an inch short of my full draw length target and finish the bow up and shoot it. It usually gets me pretty close to my target at intended full draw finished and sealed bow. With yew a little sanding and scrapes go a long way in my experience. Burnish with burnishing rod or piece of porcelain or something smooth when done sanding the bow to get it really shiny and smooth. Best of luck.
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Good sound advice by others here.Hav'nt made many yew bows but I'd be patient and sneak up on it myself.
I generally start out from brace a little closer to my final draw weight though.
I really don't see why you pulled it to 80#'s if you wanted 60#'s.You should be ok yet hopefully because it was only to 16".
Removing even amounts or counting strokes from each limb.Stay away from the hee haw syndrome of overly positive and negative tiller showing if you can.That means a little at a time.Exercize it properly between wood removal.Check amount of draw weight loss from removal at same draw length previously checked.Good place to be though with it already bending evenly.
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I'm used to wrestling really "characterful" staves to brace height, to do that usually means finding the place where a hinge (or hinges) is going to be and smoothing the rest of the stave down to the same level before the weak points become a problem. I am so used to pulling it an inch, finding the weak points, correcting then pulling 2 inches and repeating until the stave is bending nice and even. Often weak points don't appear until the bow is bending a good few inches and the stresses have all evened out. For me, this is a really good stave (two or three knots and a bit of twist and a bit of sideways correcting is a good stave !), and this stave ended up overweight by a long way. Its only the second or third time this has happened and it kinda freaks me out. Why bend it? So I can find and correct any weak points before they become a problem. They were there, they got corrected, but no-where near as bad as I am used to and now I am a long way overweight. The stave came with a bit of reflex where I could fit my little finger under the handle rubbing the bow and the bench, the reflex is still exactly the same, so no set yet, and the 16" draw on my stretchy long string is more or less brace height.
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Its one of the fundamental questions... how much wood to remove to drop a certain poundage.
It's down to experience... but to drop 20-30# requires a fairly enthusiastic rasping along the belly of each limb.
I tend to follow the mantra of "remove half as much as you think you need... then check the tiller".
Of course you have to take it off proportionally... less off as you move towards the tips (e.g 1mm off a 23mm thickness near the grip, has less effect that 1mm off a 10mm tip)
Del
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The alternative is to thin the sapwood but I have been caught out by doing this as if it goes wrong you have to start all over on another ring and it is very easy to end up going too far and lose too much weight. In this case the sapwood is relatively thin at one point and I am not at all certain reducing the sapwood is a good idea in case I go through to the heartwood at that place. What is the minimum ratio of sapwood to heartwood before performance is affected? Is 30:70 sapwood to heartwood too much sapwood for example?
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I wouldn’t recommend taking down any of the sapwood. I know others do it but the rings on yew is often very thin and can be a challenge to get to a single ring. It may not be a deal breaker to violate a ring with yew I don’t like to do it if it can be helped. 1/4” sapwood is sort of the standard but wood is wood. If you e got thick sapwood maybe consider a narrower limb design to get more heartwood to sapwood ratio. I don’t think I would even make a wider limbed recurve type bow with yew that had real thick sapwood. I think you’d be fine with a ratio of 30/70 like you say generally. I’ve got a yew bow I’m doing now that has some character and the sapwood is thicker on one side of the limb then the other. Wood is wood and we just have to roll with it and make the best bow we can with it. I certainly wouldn’t violate a ring to even sapwood out imho. Best of luck.
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The alternative is to thin the sapwood but I have been caught out by doing this as if it goes wrong you have to start all over on another ring and it is very easy to end up going too far and lose too much weight. In this case the sapwood is relatively thin at one point and I am not at all certain reducing the sapwood is a good idea in case I go through to the heartwood at that place. What is the minimum ratio of sapwood to heartwood before performance is affected? Is 30:70 sapwood to heartwood too much sapwood for example?
30:70 is fine.... 50:50 is ok
As long as you have some heartwood maybe as little as 4-5mm, just gotta work with what you have.
Reducing sapwood can be tricky as the heartwood underneath won't always be an even layer, it can swell up especially where there are undulations. Also depends on the curvature of the log, the heartwood may be cowned up under the sapwood.
If you saw the stave into 6" sections you can see exactly where the heartwood sapwood boundary is ;) :o >:D O:)
Del
BTW, you don't need to follow a ring, yes it's pretty, but not necessary.
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You probably know this, but I’ m going to post it anyway just in case. If you are that heavy, you likely don’t have a string on it, and no matter how short your tillering string is, it’s going to show you a weight greater than what it actually is.! The more slack in that tillering string, the more stack you’ll encounter more quickly as you bend the bow, and the greater the poundage will read above what the actual poundage is. Again, I know you probably know that, but I hate assuming anything, and I overshot the wood reduction and ended up with some surprisingly low poundage bows at first stringing on my first few attempts because I overlooked this concept. Otherwise, wise advice above; go slow and get a string on it as soon as possible.
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You probably know this, but I’ m going to post it anyway just in case. If you are that heavy, you likely don’t have a string on it, and no matter how short your tillering string is, it’s going to show you a weight greater than what it actually is.! The more slack in that tillering string, the more stack you’ll encounter more quickly as you bend the bow, and the greater the poundage will read above what the actual poundage is. Again, I know you probably know that, but I hate assuming anything, and I overshot the wood reduction and ended up with some surprisingly low poundage bows at first stringing on my first few attempts because I overlooked this concept. Otherwise, wise advice above; go slow and get a string on it as soon as possible.
You know for the past 15 years or so I have been using the long string to gage the weight of my bows as I build. I have done this on hundreds of bows not just a few. If the string is hanging loose somewhere between 1" and 9" It will read surprisingly close to the actual draw weight if it were braced. I normally brace a bow when it reads target weight at about 23 or 24 inches for a 28" draw bow. It doesn't seem to matter the style of the bow. I usually take it to this weight with a well-controlled draw knife but will use a scraper or rasp on occasion. Once it is braced, I use only a scraper and I never think of myself as reducing weight, I like to think I am just perfecting the tiller and when it hits its target weight, I just no longer have any more room to perfect tiller.
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I keep my long string quite tight to the stave, hanging down so it starts pulling the tips at about 3” string movement. I have found it’s a pretty good indicator of draw weight but when I started in this craft I used a very slack string which was far from accurate
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i use a string that is about 9 or 10" more than the stave. I don't remember exactly. I look for a good bend at 10" and about 5 # over the draw weight I want. This puts me at 15# or so over my potential draw weight. Plenty of room for tillering.
Stringing a bow that is more than 20# over potential draw weight is not a good idea.
I could go on about how I "sneak up" on tiller but ...
Jawge
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I, for one, would enjoy that
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Everybody seems to think that how far the limbs are bending is what gets you the draw weight, it's the string angle that gives you the draw weight, that's why it doesn't matter that much how far the string is hanging down loose. This is not theory it is a standard practice I use on every bow and have for years. And George you said exactly the same thing I did you just go through a different process if you're stringing hanging loose 10 in, and you pulled another 10 in that's 20 in now if you pull it 5 lb heavy that gives you another 2 in and that comes out to you about 22 23 in. The only difference is it doesn't matter how loose the string is because you're not measuring anything to do with the limb bending
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I got this method from Jim Fetrow many years ago.
The idea is to not stress the stave as much as possible during the process.
At no time do I draw the stave, once it is strung, to full draw weight. Once the stave is strung I go to a scraper-like tool which is for me a Swedish draw knife held almost vertically above the wood. I check tiller a lot.
I have a 26" draw. Let us assume I want a 50 # target weight (sadly, those days are gone).
Once I get a good bend I even count the strokes of my scraper. Check tiller. Pull at short draw
length to register the removal.
I look to get 40# at 20". Assuming 3# increase for each inch. That gives plenty of room to make weight.
I stop removing wood at 25" looking to get 53# at that draw length. By that time the stave as been drawn so many times at partial draw length that there should be no change.
Since a scraper-like tool has been used very little sanding is needed.
Some use the Hamm method. Get a good bend and pull to target weight no matter the draw length. That will work but...
Then there is finish sanding.
Stickinthe mud, thanks for asking and have fun.
Jawge
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Badger, I agree about the looseness of the sting. It has never been an issue for me. I never cared about getting it tight to the string.
I've made hundreds of bows using my method to ready the stave for stringing and hundreds using Jim Fetrow's tillering style.
It has been quite a journey.
Be back later.
Jawge
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I probably jumped out of the frying pan and into the fire. When I started (I've now built/completed 8 bows with two of those being children's bows) I don't know how slack my tillering string was, but it was obviously too slack. As was pointed out, its the string angle that screwed me here. However slack my string was, I was approaching and hitting a 90 degree sting angle fairly early in the process, so it was stacking and reading way high way early in the process. I'd aim for my intended draw weight at 24" thinking that would give me plenty of room to slowly reduce weight as I approached 28" without ever exceeding my target draw weight. Then I'd make a string, string it up, put it on the tree, and discover that I was already at my intended draw weight or a bit lower at 28" with some tiller fine-tuning still required.
I finally figured out why it was happening, so I started getting a string on as soon as I could string it without it being so stout that the act of stringing it would over-stress the limbs. Maybe I have been doing this too soon, because I can not seem to make a bow that will not take set. That said, the bows are not really taking set until I start approaching 28" draws, and I am now never drawing it more than my target weight...so I'm thinking it's flaws in my tillering technique/ability.
Regardless, my original point...more specifically stated is...keep an eye on the long string angle to the limbs, because the angle absolutely WILL be greater than if the bow had it's nock to nock string on it, and the closer that angle gets to 90 degrees, the greater the difference the long string poundage will be above the poundage you'd be drawing if the bow was strung...and the difference will increase exponentially with each additional inch pulled once that angle approaches and hits 90 degrees.
Like I said, most of y'all know this even if you aren't consciously thinking about it and you have the experience to know how to dial everything in with your specific process...but I just wanted to note this phenomenon for any newbies that might be trying to learn by reading all these threads.
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sometimes a bow will take a bit of set at 28 inch draw,,,,a bow with little set and one dead even,, is not much difference in performance,,
if you over compensate making the bow longer or wider,, the added mass can be a wash in performance,,
shooting through a chrono is more telling than how much set the bow has,, sounds like you are going in the right direction,, as you make more bows, missing the weight wont happen that much,,
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I have not drawn a tillering string beyond 10" in probably 20 years.
If you are going to then you do need to make it pretty tight because of string angles. Jawge
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Thank you all for your advice, it has given me the confidence in most of what I am doing but I have cut back on how far I draw the bow while tillering. I got quite enthusiastic with the rasp and the weight loss program puts the draw weight at 50@18”, so about half of where I was. Figure I need to lose another 30lb but it’s getting there.
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I have not drawn a tillering string beyond 10" in probably 20 years.
If you are going to then you do need to make it pretty tight because of string angles. Jawge
George when you say 10" do you mean 10" plus the 10" loose string?? If so, that is 20 " draw. If you just weigh it like you would as if the bow was braced and forget all about tip movement, it makes it a lot less confusing.
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Badger, I pull the string down, mark it as a starting point, and measure down 10". That's it. The long string is only drawn 10". Jawge
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George, you and I have gone around and around on this for a long time. All I can say is that if you are drawing some kind of connection between how far you are moving the string and measuring the draw weight then you are giving out very bad and wrong information. There is no connection between string movement and draw weight period. You measure the draw weight the same way you do on a braced bow, you simply look at where you are drawing it to and it makes very little difference how much slack you have in the string.
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could someone post a video on this process,,or at least some pics,,
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I've only made a couple of hundred bows using that method.
This is just a method for determining when the stave is ready for the short string...that is no more than 15# over final target weight.
That's all my method does.
Sorry you can't see that but it does work.
Jawge
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20" draw test after brace has been the length that I go by for knowing what it will be @ 28".For the draw weight I usually want these days I need it to be 31 to 33 pounds to get a 45 to 48 pound bow @ 28".
There can be a variance of 6" of bow length and it is still very close to the same with moderately straight limbed bows with equal reflex.
Recurves are a different story.
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I don't do videos.
There is info. on my site, however and in several articles I've written.
http://traditionalarchery101.com
But this not my first ballroom dance so you can be sure I've used this method on my bows to help me determine when the stave is ready to be strung..
Just trying to help those just getting started from making the same mistakes I did.
How slack the string is not important. I've said that through out my bow making life and a couple of times above.
Jawge
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I don't do videos.
There is info. on my site, however and in several articles I've written.
http://traditionalarchery101.com
But this not my first ballroom dance so you can be sure I've used this method on my bows to help me determine when the stave is ready to be strung..
Just trying to help those just getting started from making the same mistakes I did.
How slack the string is not important. I've said that through out my bow making life and a couple of times above.
Jawge
George, you say how slack the string is does not make a difference. With your method it is critical. Because you are giving it 10" of pull. Every 1" of slack in your string will make about a 3# difference. If you ignore how far you are actually pulling the bow and just take it to whatever draw length you are looking at on your tiller tree then the slack makes no difference. You can check the weight on your bow at any stage you want simply by checking it the same way you check a braced bow., It does not make much difference if it is braced or not. I can't think of anything that could possibly be easier and less confusing.
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Steve, I said previously in this thread that I pull the t string down to remove slack, mark it, and measure down 10" from there and proceed.
All this method does is determine if the stave is ready to be strung...bending well and around 15# over final target weight.
So with your method how far over final draw weight is your stave before you string it? It should be no more that 20# over.
Jawge
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George my method just determines the current weight of your bow in progress. I do it from start to finish every time it goes on the tiller tree. I can brace it whenever I choose which is usually between 10 and 15# over weight. If I decide to brace it when I hit target weight at 23" that will put me over about 15#. The most common question new bow makers have is they don't know how strong their bow is, The easiest way to find out is to simply put it on your tiller tree and measure it the same way you would a braced bow. It is more than accurate enough and by far the most accurate way I know of. It cannot get any simpler. You don't need to make allowances for anything. Just pull it down and look at the weight. You ignore how far the limbs are moving and just look at the length of the draw.
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Good, Steve. I am glad it works for you.
My method does the same thing but makes how the stave bends is important too.
A good tiller starts right from the outset.
It is an extension of floor tillering.
Yes, new bowyers don't know when to go to the short string which is why I developed this method.
Jawge
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George my method has nothing to do with tillering, or anything else. It serves one purpose it tells you what the weight of the bow is. You can use the long string for tillering if you choose to but it is nice to know exactly where you are in the process. That is all it does is tell you what weight your bow is at whatever distance you choose to measure it. When my bows hit target weight at 23 or 24" That is where I usually choose to brace them but you can do whatever a person chooses to. We have more control over the process when we know the weight.
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Knowing the weight of the stave before stringing is crucial, Steve.
Jawge
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I agree George, thats what my method does. I don't know why this is going past you????? I have explained it more than a dozen times. You check the weight with a loose string before stringing. You know what the weight is all through the build. You only have to remember one thing, that is the bow does not have to be braced to check the weight, thats all you need to remember. The builder can do whatever he wants with that information.
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Steve, I never said it was past me. I am glad you like your method.
Likewise, I just don't understand why you don't understand mine and see its utility.
That's ok but I do assure you I am not passing on bad info.
I have used this method since the mid 90s with much success.
So be it.
Jawge
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arent you guys talking about the same thng but something getting lost in translation
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The easiest way to find out is to simply put it on your tiller tree and measure it the same way you would a braced bow. ....It is more than accurate..... It cannot get any simpler.......
Just pull it down and look at the weight. You ignore how far the limbs are moving and just look at the length of the draw.
Steve,
help us out with a hypothetical example or maybe a sketch
for example, a bow you are tillering and hope to finish at 50# at 28". during tillering,
1. if I pull 1#, the nock in the tillering string measures 5" below the handle
2. if I pull 50#, the nock in the tillering string moves down 10" to a point 15" below the handle
when do you check it next? when do you stop tillering?
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Willie, ignore how loose your string is as long as it is not over about 10" I prefer 5" or 6". Anyway in the case you gave the bow would be about 50# at 15". And it would measure very close to that if it were braced. I am not using any method I am just reading it the same way I would a braced bow. I use weight instead of the profile of the bow to monitor set so I like to know what it is all the time.
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i edited the question as you replied.
When my bows hit target weight at 23 or 24"
so as long as you stop and brace at about 23/24", it matters little whether you started with 3" droop, or 8" droop
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Yes, but I want to know more about the weight as I build also.
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seems pretty simple to get to 23/24. what additional info do you look for?
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seems pretty simple to get to 23/24. what additional info do you look for?
While I am building I set a new benchmark every time I take wood off. And then after drawing to the new length I look for any drop in weight at my last benchmark that might indicate early stages of set.
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for instance. if you are at 24" with 50 # before you do a wood removal,
then after the scraping, you measure 50 # at 25".
then do you let it rest for a minute or two then see what weight you get at 25" on a second pull?
how much weight loss at 25" would tell you to do something different? and what would you do different?
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i find Badgers method intersting as a theoretical mind game and I see the thought behind. but: isn't set inevitable to a certain degree? further: isn't the inevitable amount of set different from one piece of wood to the next one? So how can these uncertainties be implemented into the so called "no set method"? how do I distinguish between the inevitable set and set induced by my bad tillering?
cheers
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i think Badger method detects a weight loss which precedes set, and he monitored enough bows to get a good idea where he will end up set-wise by seeing how the bow responds at 23/24"?
lowering the weight goal for the finished bow seems to be the most likely action if a bow shows the preliminary symptoms too early.
or getting the outers working more?
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Thanks Willie.
I'd say that "weight loss which precedes set" is already set. Maybe "visible set" would be more precise.
What you say basically makes sense. But when and how much is "too early". Looks like also with this method you rely a lot on individual experience to interpret the situation...?
Cheers
Edit: How much loss do you accept as inevitable practically and when do you react by lowering weight goal or adapting your tiller? :) If you don't see where the set - according to the measurements - happend how do you know you need to scrape the outers? In my bowmaking set mostly gets visible first mid to outers...
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willie, to answer the question you addressed to me..I look for 10" of string travel...not nock travel.
Mirroring the finished bow ...the nocks only move 2 or 3".
Jawge
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I am going to have to go out to the garage and play with long strings and scales for a while for this to make sense. The words are starting to spin around in my head...
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Edit: How much loss do you accept as inevitable practically and when do you react by lowering weight goal or adapting your tiller? :)
hopefully Badger can quantify what he measures and where. I have used this method with success, but have not developed enough experience to know how much to back off.
how do you know you need to scrape the outers?
I presume leaving the outers a bit stiff initially could be one way utilize this method.
Having done so, and upon seeing weight loss, one might assume the inner limbs are getting to thin and the bend shape needs to move "outward"?
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I should probably start another thread to discuss that. It's not a real short answer. I like to use as little limb working as possible. Now even though I like to use as little as possible working 90% of the time I still have to use almost the whole limb. My primary go to area is right off the fades I'd like to leave about 3 inches that's pretty stiff I can go back into that 3 in and get quite a few inches of draw if necessary
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sometimes I am making a bow for someone,, thats wants a specific draw,, and I have to live with some set,, its a bit different if making for myself,, I can stop when the draw is any length,, or reduce the target weight,,
but for most hunting purposes,, a bow with a little set is still very deadly,, so have to factor that in to what is always a give and take with performance and practicality..for that bows intended use,,its complicated,,, (-S
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sometimes I am making a bow for someone,, thats wants a specific draw,, and I have to live with some set,, its a bit different if making for myself,, I can stop when the draw is any length,, or reduce the target weight,,
but for most hunting purposes,, a bow with a little set is still very deadly,, so have to factor that in to what is always a give and take with performance and practicality..for that bows intended use,,its complicated,,, (-S
I don't think I have made a bow in life without some set. I have come pretty close a lot of times though. Thats where the fun comes in for me is fighting set.
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I just try my best, what else can I do,, ;D great info by the way
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Thanks Guys!
Interesting method and topic for sure! I'tempted to try,...at least partially to see the hidden loss when tillering....just curious to observe that. But basically I'm very intuitive with my bowmaking and my method switches greatly from bow to bow. Some bows are almost ready tillered to 28" when roughed out, some need more careful progress...
Cheers