Primitive Archer
Main Discussion Area => Bows => Topic started by: Badger on June 18, 2014, 03:49:28 pm
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Here is a bow I am just getting started on, I have it cleaned up and very roughly floor tillered, I just glued on some ipe nocks. The bow is 54" nock to nock, BBO, target weight 50#@24". I copied Marks designs to a large extent with a few touches of my own. At present the bow weighs 19 oz, my projected finished weight is 17 oz. If I go to far below that and start to show signs of stress I will drop the bow to 35#.
Starting with 3 3/4 iches of reflex I don't expect it to creep up as I tiller because I did not glue it into perry reflex. I pretty much formed the wood then wrapped it with maybe 2" of relex induced under light pressure. These have a higher than normal failure rate so I will post as I go and hope it don't break. Target speed is a minimum 245 fps with 200 grain arrow, otherwise just another practice bow.
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Progress, I have it out to 50#@15" on the long string, will continue until I get to 50#@20" then brace the bow. About 1/4" less reflex.
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Looking fine so far Steve. Could be a screama'!
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Here we are at 17" and 50#. Left limb bending a little too much mid and right limb a bit stiff, I should have that evened up pretty good by the time I hit 20" then I will brace. Most important thing I pay attention to on a flight bow is the condition of the wood. Makes a huge difference in the end product. I try not to loose any weight due to compression, regardless of visible set.
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V Interesting...
Del
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Here it is at 50#@20" on the long string and me bracing the bow.
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Thats it for today, scary part tomorrow. So far only lost 1/4" of starting reflex. I have 4" to go.
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Very nice Steve. Flight bows are such fun to make ::)
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Those statics look too cool Steve.
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That's awesome steve! Thank you for sharing some of your work, you are an inspiration :)
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Sweet...I love tillering those kinda designs...they give me a boner!!! I find first brace is always fun with those...I find it best to brace with no more than ten pounds left,and you have to have it at least ~4" for a first brace otherwise if too much weight left and too low of a brace and they come flipping back on ya...lol :laugh: getting your bend as close to perfect before brace is very critical with those...looking good from here ;) ....I got lams all prepped out ready for a short r/d static,but haven't glued it up yet...been busy...lil rocket launchers they are
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The thing I was a little unsure about was how the mass figure would factor in for a deflexed bow. I build very few deflexed bows. I know they make for lower mass but not sure how much. I am at 17.9 right now, no more than 1/2 oz left in tillering and about 1.5 oz comming out of handle. I will finish at about 16 oz, 1 oz below projected. I kind of hate doing buildalongs because of the risk of breaking but thats real life and how it goes sometimes.
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What's your front profile widths if ya care to share? Your on the edge for sure,but from what I can see I think you still have enough wood for your intended specs....the last one I did was 62" ntn n 57@27" n only weighed 18 or 19 ounces finished...and it held its shape great and the wood was still very healthy
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54" is pretty short but that's what you need for flight
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1 1/4 at the fade and down about 1/2 the limb it start to taper
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Great looking design, just has the look of a bow holding good arrow cast and smooth draw. I'm gonna watch this to see what's next, thanks for posting it.
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Looking good Steve,looking forward to seeing more. :)
Pappy
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I think ya have just enough..as long as ya don't crowd your tiller too much n got good materials it should hold...I also made a 55.5" R/D stiff handle osage selfbow with a shelf cut in pulling 44@26" n its only 16.9 ounces mass...and its still shooting yet a year and a half later
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I agree with you, on a shorter bow no real need to crowd the tiller. Barring a screw up on my part I should be ok.
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Looking good! Wish you the best, Badger. Jawge
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Well she finished out quickly this morning, waiting for someone to photo full draw pics. Like to share a couple of tips here that can be helpful to anyone even experienced bowyers. Knowing when to brace a bow can be a little iffy sometimes, especially reflexed bows or recurves. It really doesn't have to be. When I braced the bow last night it was pulling 50#@20" on the long string. After bracing this morning I put it back on the scale and it measures the same braced as unbraced. Of course bracing a bow adds a lot of stress that an unbraced bow is not experiencing so once it is excersized I expect to loose a few pounds just to wood compression. As expected this happened. I lost 3/4" of my reflex and about 2 1/2# draw weight just in compression losses to the wood. I now have 2 3/4 reflex and expect that to drop to about 2 1/4" by the time I shoot it in. 2" was my goal.
As you can see in this pic I had an unexpected surprise, a little black dot developed into a hole that goes almost 1/3 the way across the limb. I decided not to touch that area anymore but it does leave me with some lack of confidence in the bow. Hopefully I cna test the bow out today if the sunshine cooperates, my chrono doesn't seem to accurate in bright sunlight even with the diffusers, I may have to wait till morning when it is overcast. 245 fps with 200 grain arrow is the goal.
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Ouchy! I don't like that either Steve. Better wear glasses yanking on it. I hate to take a static to the eye.
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Yep Chris, I wasn't too happy about that knot. Another concern I have is that the belly and boo back together measure just a little over 9/16 thick. On a 64" bow I like the thickness to be at least 3/4" before I consider even cutting in a shelf. I know on a shorter bow I can go a little thinner but not sure how much before the handle pops off. So once I cut in the shelf I will have to test that out. Not out of the woods till the bow is finsished and shot in. Either way I feel the bow is a success and I plan to build another with a few minor changes. I can see why Mark likes this design so much, the force draw is phenominal! It builds weight right at the start and then falls off about 15" into the draw. I have high hopes for this one or one very similar.
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Could you just narrow the pass up more rather than cut a shelf in? Maybe that would keep it rigid and get you closer to center anyway.
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Could you just narrow the pass up more rather than cut a shelf in? Maybe that would keep it rigid and get you closer to center anyway.
I htought about that but the little flight arrows are real narrow and stiff, best shot right at center if possible, so I need to get as close as I can. I cut it about 1/16 before center, if it lets go I will just use a power lam in the next bow. To stay in the simple composite class I have to keep my built up handle area within about 12" I think, they don't specify where the building up of the handle has to happen so a power lam would be acceptable.
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245 fps! Wow
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Looking good! I'm waiting in anticipation for the chrono results >:D
I haven't posted any of them for a while but i'm still on the r/d static trip. For me this is close to if not the fastest design for a wood bow. My black locust one is still pushing 195 - 200fps at 8.5 gpp, it's dropped a bit but not much. For quite a while I tried to make just plain reflexed statics but the wood loses too much in compression by full draw. Deflex is good!
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Well, I went to test it out and the weight had come back up. I get this quite often on reflexed bows just off the tiller tree then rested. Hitting 51#@21" so I need to tiller it back down to 24" and 50#. I thought I would run just one quick short draw test on the chrono to see how the efficiency was looking, I drew it about 17" and hit 195 with a light arrow so it is on track to do what i am looking for. Knock sheered off on first shot so I will repair that and drop the weight a bit. My electronic scale might be more accurate than the hanging scale that I tested with while tillering so that might be part of the weight gain.
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That's pretty good Steve. You probably lost a bit of speed when the nock failed
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The bow looks like it has some great potential for blowing past the 400 yard line.
Don't forget you can go down to a 23" arrow in the primitive flight divisions, so you don't have to take it all the way to 24" if it feels like it is right on the edge.
Alan
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Sounds like it's coming along nicely, and just like any other bow build,always some challenge to contend with as you move along. :) Looking forward to seeing the final results. :)
Pappy
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That's fast at such a short draw Steve. I bet she rips at a full draw!
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Chris, bow is not really on the edge of breaking, just on the edge of taking set. I could probably tiller it out to 28" but I would loose a lot of relfex and some of the snap.
Allen, glad you chimed in. I was about to make up a bunch of 22" arrows for this bow. I keep forgetting primitve stops at 23'.
Something I see almost everytime I make a bow using no set tillering is I get just a little bit of forgiveness and healing if I don't go too far. Say I overdraw 1" and it looses a pound or so. When it sits for a few hours the weight comes back and I get another shot at tillering the weight down instead of compressing it down.
It makes me think of a legal way to cheat at a weigh in just the way boxers do at weigh ins. They sweat off a bunch of weight before a fight to make weight and then over the next 24 hours rehydrate and put on 5 or 6 pounds. A flight bow could be slighlty over drawn for a temporary weight loss to make a weigh in and then set back down for a few hours to heal up. I tries this with my broadhead bow and could bot compress an ounce out of it even with a 3" overdraw. I had to go back and scrape another pound out of it.
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wow, i am enjoying this,
chuck
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Ok, for once everything came out just right.
I started with 3.5 reflex and finished with 2.25 ( predicted about 2)
stored energy came in at 43.5 @24" draw ( this would exrtapolate out to almost 63# or 105% if drawn to 28")
Chrono speed came in at 248 fps with 200 grain arrow short drawn by 1/2". 245 fps was my goal, I should hit about 253fps)
Efficiency I am most happy about at 53.5% with a 200 grain arrow.
Mass came in at 16.6 predicted was 17.0
I wiill polish it up a bit and post a series of photos.
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Yo the man.
I haven't got over 200fps yet :-[ :'( mind I'm working on something ;)
Del
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Wow, that knot looks worse than the knot I just fixed in my Hickory backed osage, in a very similar spot too. The little branches inside the knots were chrysaling.
Great bow. What do you think you would get at 10gpp?
Mike.
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I only did one shot and got 181 which I was very pleased with for a 24" draw. Arrow was slightly under 500 at 488. This is my best bow to date that has survived numerous shots and was pretty well worked in when tested. I have another bow set aside for the broadhead shoot drawing 50#@28 and am hitting 189 with it.
I actually have specific records I am chasing and will build for those records. Doesn't mean I won't enter the bow in other classes as well. This bow will hit about 28 fps faster than the one I currently hold the record with. My broadhead bow should be good enough as well. I need about 228 yards with a 500 grain broadhead. 184 fps will do that under the right conditions.
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That is excellent Steve. Now put that bow away and save it for the flight shoots
P.S. I started working, slowly, on a heavy recurve. I decided to try a selfie
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That is excellent Steve. Now put that bow away and save it for the flight shoots
P.S. I started working, slowly, on a heavy recurve. I decided to try a selfie
How long of a draw are going for Mark?
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It will be 32"
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You guys are awesome.
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8)