Primitive Archer
Main Discussion Area => Bows => Topic started by: alwayslookin on March 12, 2015, 06:23:04 pm
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So I have been coming in way under weight on my last couple bows and I thought I figured out a way to not this time. I would use the long string and measure the weight from slack to 6 inches down as a guideline and thought I really had it figured out well that didn't correlate at all when I put the actual string so this one is under what I want to. I can't seem to get a fifty pound bow for my life. This one is higher than the last one so that's a plus. I kept this one very long so I can chop some off and possibly flip the tips. How much weight does flipping the tips add? Anyways check my horrible tiller out and let me know where to scape. I was getting a little discouraged cause it seemed like everywhere I thought I should scrape wasn't doing what I thought it would.
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You are not useing a gizmo or a straight edge are you, limb on the right is doing all the work inside two thirds of the limb ain't doing anything the other is better but you need to get a straight edge six inches long there should be very little differance in gap the length of the limb
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the outer parts of the limbs need to bend more,, you have too much bend toward the handle
when you tiller next time,, get the outer limbs moving a bit and then work toward the handle
you will get the 50 pounder on the next bow :)
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A tillering gizmo will solve your not knowing where to scrape problem.
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Hey man, Your tiller is not as screwed up as you thought....the right limb in the photo is just bending a slower arc than the left (right is flatter but still bending) if you do a little mid-limb work on the right to get nearly symetrical to the left you have all sorts of options flipping the tips, piking her down or both. You need to go slow though....as the right bends a little more the left will bend a little less.....so sneak up on it real slow.
I cant really more because you did not say what bow length was, what draw length you want, ya need to know that to go about gettin a plan.....if you are within 8-10 pounds of what you wanted it is doable.....but like I said right now your the only guy that knows what ya got and where ya want to go >:D bein a smart-ass. I would leave the tips be for now just even out the midlimb bend and if you need to pike and flip you'll have plenty of wood to work with.
Course everybody will tell I'm nuts anyways....but you can think about it.
rich
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I found that for a 26" draw long string tillering out to 10" and looking to get target weight at that distance with the long string puts you 10# over target.
Jawge
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I would take Rich's advise. Your not too far off and you still got enough meat on the bone if you need to pike it to up the pounds a bit. I believe I was told it will yield 5# per inch piked but someone can correct me if I'm wrong.
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In my opinion, the righthand limb is dangerously close to breaking catastrophically at the fade, right at the chrome door handle.
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One thing I learned during floor tiller stage is to get it bending mid limb and outer first, then maybe use the long string find out where to remove material from inner sections. End up with a lot more material in fades that way and less chance of hinging.......for me anyway.
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Glue on handle? That convex fade plunging down to flat land is a recipe for disaster.
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I've salvaged a bow with a similar problem once by adding in the central 60 cm / 2ft a few mm of plant fiber backing (sisal cordage untwisted to raw fibers). Reverse drew the bow before gluing the backing on (hide glue), so to pre-stress the fibers when dry. Backing applied well over the fades, and fades out mid limb. Let it dry for a week, then restarted tillering. If it still isn't drawing enough, repeat. Afterwards, I backed that bow with cherry bark to cover the fibers. In addition, it makes the back really water proof.
Two years and many hundreds of shots later, it's still shooting fine. Other specs: red oak heart wood, 67", last 2" mildly flipped, pyramid front shape from 4.5 cm /1.8" outside fades to 1.3 cm / 1/2" at tips. pretty even thickness taper, c. 1.4-1.5 cm thick. Slightly toasted on the belly, working fades and grip. Draws about 45# at 27" but can be drawn no problem to 29", has c. 1" resting set, 1.5" after shooting, shoots c. 155 fps at 10 gpp.
Joachim
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Thanks for all the responses guys I really appreciate the insight from the pros. The right limb was actually way to stiff before and I noticed the fade was longer and was causing that so I removed some of it to even out and may have went a bit over board.
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I've salvaged a bow with a similar problem once by adding in the central 60 cm / 2ft a few mm of plant fiber backing (sisal cordage untwisted to raw fibers). Reverse drew the bow before gluing the backing on (hide glue), so to pre-stress the fibers when dry. Backing applied well over the fades, and fades out mid limb. Let it dry for a week, then restarted tillering. If it still isn't drawing enough, repeat. Afterwards, I backed that bow with cherry bark to cover the fibers. In addition, it makes the back really water proof.
Two years and many hundreds of shots later, it's still shooting fine. Other specs: red oak heart wood, 67", last 2" mildly flipped, pyramid front shape from 4.5 cm /1.8" outside fades to 1.3 cm / 1/2" at tips. pretty even thickness taper, c. 1.4-1.5 cm thick. Slightly toasted on the belly, working fades and grip. Draws about 45# at 27" but can be drawn no problem to 29", has c. 1" resting set, 1.5" after shooting, shoots c. 155 fps at 10 gpp.
Joachim
hmm that's interesting would jute work in this application?
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when you tiller next time,, get the outer limbs moving a bit and then work toward the handle
This is funny, because I HAD to learn to do the exact opposite, to start getting good tillers early on. I leave the limbs full thickness, and consistent thickness, but shape the front profile early on. This way the bow PREDICTABLY bends at the first 1/4 of limb length in the first few inches of draw on the tree.
BUT, as soon as I have that few inches of tip movement balanced, I stay out of that area COMPLETELY, I actually tape it off or at least mark it, and start chasing the bend out along the limb.
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If you cant afford a scale, find some way to mount that bow on the wall, and get a 50 lb weight (old barbell plates, bucket of rocks, big chunk of log, whatever) and once you get the bow to low brace height, hang the weight on the string, step back, look, and mark where you need to make changes. Don't let it sit too long, bu this will ensure it never gets pulled past final draw weight, which helps ALOT to reduce set.
You can rig it so that when the bucket touches the floor, you better be done.l
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If you want a 50# bow then ALWAYS pull with 50# weight unless you can see a tillering problem before you have pulled that much.
So on a long string pull 50# and remove wood until the tips come back 6". Then go to short string and pull 50#
If you always pull 50# you'll end up with 50.
It is a big mistake to think you don't have to pull 50# to get it back on the long string.
Del
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What do you guys think will give me the most poundage I can either flip the tips keeping length as is or I can pike 1in or 2 off each tip? Just wondering which one I would benefit more from.
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Making a bow shorter to pick up weight can often be a case of chasing your tail. You can end up where you started, you just have a shorter bow. The limbs become more stressed and the bow takes on set. Net 0 gain. I have piked a bunch of them over the years, but prefer to plan in the length I want, and work from there. Flipping the tips can sometimes cause some of the same issues. I don't know the length, but I would say flip the tips before piking. If your real long, 70 inches for a 27 inch draw for example, then cutting a few inches off each end will still keep you long enough, 66 inches or there about. If you are already that short, then flip the tips in my opinion. Should up the weight a bit if your tiller is good. If not, then get it right first.
I will still come in light on some. Not by much and not often, but it still happens especially if there is a particular issue I am working around so don't beat yourself up over it. Identify WHY your coming in light, and modify your technique. For me, getting a string on it early is key. That first requires a good floor tiller so all is pretty even while bending 5 inches or so. Then check it with a long string moving the tips that same 5 inches while on the tiller stick. Get the limbs even with a straight edge at that distance. Now, get a shorter sting on it braced an inch or 2. Work the limbs moving an inch at a time. Get them bending right and even, and then shorten the string and increase the brace height to 3 inches or so. Keep taking baby steps until you have it braced 5 inches or so. Perfectly even at brace. You will be heavy at this point, so just start shedding pounds slowly while keeping the tiller even. Check the weight and see at what length you hit 50. 15 inches? 20 inches? Your good to go. Tiller has to be right from the moment you start flexing the limbs. The earlier the better off you will be. If it's near perfect once floor tillered (not likely), then your golden. If not then get that right before anything else happens.
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Best way to make a 50# bow - do what Del suggested above and start again. Trying to make this attempt 50# is as also said above 'chasing your tail'.
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Don't listen to Mike, his bows always come out at about 25lbs ;D
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More like 2.5#........... ;)
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Haha thanks guys. Slim Bob very good read thank you for your thorough response. The reason I asked I'm not trying to chase my tail exactly I left this bow extra long 71 inches just in case I needed to pike it a bit. I think I will shorten it a bit and then just leave it as is and keep working on my Osage stave I have. I will be getting a bunch of mulberry and crepe myrtle thus week too so I should have some decent wood to work with.
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if you shorten it ,, it is possible to gain some weight and performance, there are issues as stated above,, but if you are careful,, positive results can be obtained,, if you are unhappy with the way the bow is now,, there is no risk in fine tuning a bit,, sometimes when a bow is too long, the extra mass really takes away from the cast,, and may add hand shock,, it might need a little trim :) chasing ones tale is very common, sometimes the tiller may not look perfect,, but the bow shoots great,, looking perfect can be the enemy,, at that point you have to decide if you want the weight and good shooting bow,, or the "perfect" looking bow ,, the later can sometimes end in underweight and still not "Perfect" looking tiller :)
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if you shorten it ,, it is possible to gain some weight and performance, there are issues as stated above,, but if you are careful,, positive results can be obtained
I added an excel sheet where you can input current bow length and draw weight and desired draw weight to see how long the bow should be (and therefore how much you should shorten it). Also works for thickness (e.g., for knowing how much you should shave off to lower draw weight to desired level).
Suppose your bow draws 35# at 66", it should be shortened to 58.6" to get to 50# assuming the wood can take the extra stress. (this can also be estimated if you know the wood's stiffness and elasticity).
Joachim
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thats cool joachim.. thank you
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Thanks guys for the input. Joachim that's cool I'm gonna try that out.