Primitive Archer
Main Discussion Area => Bows => Topic started by: k-hat on February 18, 2013, 10:47:57 pm
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I cut some sections from a 2' diameter tree about a year ago and they been dryin in billet form since then (well, they were some ugly billets, cut'm out with a chainsaw). Took off the outer 1" or so of wood the other day and worked it down to a ring (thickest hackberry rings i've seen).
(http://i1216.photobucket.com/albums/dd374/k-hat/100_1665.jpg)
Here's before chasing: (told you they were gnarly!)
(http://i1216.photobucket.com/albums/dd374/k-hat/100_1662-1.jpg)
Here's after with initial profile rough cut with bandsaw:
(http://i1216.photobucket.com/albums/dd374/k-hat/100_1675.jpg)
Doing a pyramid, 2" wide to 3/8" at nocks:
(http://i1216.photobucket.com/albums/dd374/k-hat/100_1674.jpg)
My plan is to splice these together ala Marc St. Louis to get the r/d profile after i temper in some reflex into those limbs.
gonna do a fishtail (w) splice, haven't decided if i'm going to recurve it at all. I'm going for a 28" draw, right now she'll be about 62" ttt and have 26.5" of limb on top and bottom.
Suggestions/thoughts are welcome ;)
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Honestly that's asking too much IMHO. And the pyramid front profile doesn't fair too well with a R/D side profile. Not enough width there in the working limbs to take all that stress. Wish you hadn't cut the front profile out yet :-\ it might hold together but it'll be way overstressed and take lots of set even if it is tempered IMO. Hackberry does not like to be overstressed(set),but it will bend far before breaking.
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Hmm, I was modeling after Marc's elm r/d bows, seemed like they were slightly pyramidal with a mild thickness taper from the last time i looked at them, but i may be wrong. I know hack isn't elm, but it behaves very similarly (i made this wider than the elms). It's about 1-3/16" wide at midlimb. I have some elm i was considering doing this on as well, so I'll mull over it before i proceed.
Thanks for the input hawk, i value your experience!
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You'll only have 20-21" of "real" working limb for a 28" draw....and with it only 1 3/16" at mid limb is not enough...you won't have enough mass to ask for that much for that draw at a hunting weight. And that's pretty much a big period.
I think the most id do is splice em straight or slightly deflexed,and temper in a lil reflex in the working limbs,and flip the last 3-4" of the tips to give ya a starting setback of 2-3"...and tiller it out to 40-45@26" at the most and no more than that. Even that is maxing it out to its fullest healthy potential.
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I guess maybe i'm expecting hackberry to be too much like elm. This is the bow i was modeling it after:
http://www.primitivearcher.com/smf/index.php/topic,21505.msg293077.html#msg293077 (http://www.primitivearcher.com/smf/index.php/topic,21505.msg293077.html#msg293077)
I figured since it's hackberry i'd make the limbs wider, and with a couple extra inches in length I'd get the 28" draw out of it, but this is a first so i'm just speculating.
I've got a chunk of elm that would actually be just right for this treatment, so i may shelf this one for now and try the elm.
Thanks again for the input blackhawk.
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Marc's is more of a subtle(convex) taper instead of a true straight line pyramid taper like your layout lines are.
Don't corner just cus I said..I just personally have had zero luck 4 times trying to make hackberry bows into a short compact high stressed design.....they're might be someone who will think differently than me...or who knows maybe you have an exceptional piece of hackberry there?
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yeah i noticed that when i looked at it some more. I may have enough wood left to adjust the width taper some. I'll see about that first. I may yet go for it and see how much I can get out of it. If not, i'll try it on the elm blank that i have first. It's a prime candidate. The handle was going to be about 10" long because of a couple knots i was trying to keep out of the limbs, but i decided I could cut it and splice it either normal or r/d style and not have so much handle area. We'll see if anyone else chimes as well. i don't know if this piece of hack will be exceptional... can't decide if these uber thick rings are a good thing, bad, or indifferent!
Thanks again :)
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I think the bigger growth rings on hackberry is a plus...because you will have less early wood in your bow..because the early wood in hackberry is super porous full of nuttin but dead air pockets making it really brittle stuff. ...and one of the reasons why hackberrys density is so low
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Good point. Makes me want to do an sg test. I'll try it on a scrap piece and see.
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SG tests at about .7, which puts it well above average for hackberry (think it averages below .6). That's definitely in its favor!
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I'm lookin forward to seeing how this turns out. That is some seriously dense hackberry! Josh
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Hackberry is very common around here, and a while back a group of us made a collection of man-tall Hackberry longbows done in the English manner .... all < 50lb.@28” They all shot fine , no problems ...
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Well, after a brief discussion of SG, and taking blackhawk's advice into account, I went back to my billets and looked them over. I had fortunately left enough wood to make some adjustments:
I moved the grip/fade area around a touch and redrew the width tapers. Now both limbs will start at 1-7/8" width for 6", then a mild taper (convexish) through midlimb to the tips. This leaves me with a full 1.5" of width at midlimb on both limbs. Once into tiller, i can adjust the width as needed if it calls for that. i don't think i'll recurve it, just a basic deflex handle with reflexed limbs (about 3" is what my caul can do). I'll still end up with 26.5 inches, maybe a hair shy of 27" of limb length to take the strain of the design.
Wish me luck, and thanks for the input. Will post progress :)
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I built a hackberry with pretty close to those same dimensions awhile back. Im gonna try to post this link from my phone. Well I cant get it to work. http://www.primitivearcher.com/smf/index.php/topic,34522.0.html
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Nevermind I guess it did work. Wish I could remember how I did it. :)
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I like that one, can't believe i missed it when you posted it. Thanks for the confidence boost.
What i still haven't figured out is if a r/d design is more or less strained than others?? it seems to me less or about the same (would a bow with 2" of deflex and 2" of reflex be as strained as a straightlimbed bow?), but maybe i'm thinking about it in the wrong way.
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For kicks n giggles I split out a sliver of a hackberry that had an almost natural r/d profile because of this post...its near same dimensions...62" ttt....1 7/8" wide limbs for 6" then semi pyramid taper to just under 3/8" nocks with a 1 1/8" wide handle section.....I tillered it last night n today and shot it all in...its 50's@25"...haven't officially measured it yet tho. I started with 2 1/2"+ of setback and right now at rest it sits at 5/8" setback yet and it'll prob lose a hair more after a few hundred more shots for sure. The only difference with mine is that it bends in the handle just as I hit full draw...its barely visual but it does which gives me more working limb and lessens the stress than a stiff handle which you want to do with yours.....I think mine could go to 28"...but it would take another 5/8" of set I'm sure....if this was a stiff handle bow it would take even more set and too much of a loss for me or possibly breaking? But it would def be just going over the redline in my book. I'm sure you can do it but keep it to a 24" draw...
Ill start sealing mine n post it in a few days for your viewing pleasure
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Showoff >:D ;)
Mine's still in limbo, got sidetracked by some sage ;D
Did you temper it? I know you know but from your description it sounds like you whipped it out pretty quick.
Look forward to seeing it.
I'm gonna give this one as much of an advantage as possible from a design standpoint (width and taper), and tiller till she gets close to losing more reflex than i'm comfortable with. If 24 then 24, but if more then great. We'll see what she does.
Thanks again for the advice!
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Yeah..I tempered it. And it don't take long to make a hackberry bow ;) .....I just dyed it n threw the first coat of oil on.