Author Topic: Got a 60" Hack-B recurve, only 17" of working limb each limb, got a couple Qs...  (Read 4709 times)

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Offline toomanyknots

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Ok, I got a hackberry recurve in the process of being turned into a bow. It is about 60" ntn or so, might actually end up 59" or so.  The recurves are like 8 or nine inches of static non-working recurve. They are bent at a 90 degrees angle. It gets worse. It has a none bending handle as well, maybe like 10" or so. Over all, after measuring it, I saw that there will only be 17" of working limb for each limb. Yes, I should of made it alot longer, but now that I got it all ready to be tillered, I figure I might as well go through with it. I don't really have a goal weight or draw length in mind per say, but 28" would be great.  ;D Here are some the questions I was wanting to ask everybody:

- Should I back it? LOL I can throw some linen of it real quick, but I'd love to get away with an unbacked bow.
- How wide should I make the limbs to keep the bow from likely tension failure and excessive set at a 28" draw? I probably got 3" or so of width I can work with.
"The way of heaven is like the bending of a bow-
 the upper part is pressed down,
 the lower part is raised up,
 the part that has too much is reduced,
 the part that has too little is increased."

- Tao Te Ching, 77, A new translation by Victor H. Mair

Offline KShip85

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I'm no bow expert but my experience with hackberry I'd definitely temper the belly.  Hackberry to me has always seemed better in tension than compression.  With working limbs that small I'd worry about serious set.  The only tension failure I've had on a hackberry bow was a warbow that was horribly designed with some twist that I lifted a splinter on trying to string when I was bending it too much mid limb.  That being said I'd probably make the limbs at least 2 1/4" or more.  I'll be curious to see how it turns out as I've got some hackberry strips cut for a backing on a 52" ERC Molly as an experiment.
Kip Shipley    Bloomington, IN

Offline toomanyknots

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I bet you hackberry would make an excellent backing.
"The way of heaven is like the bending of a bow-
 the upper part is pressed down,
 the lower part is raised up,
 the part that has too much is reduced,
 the part that has too little is increased."

- Tao Te Ching, 77, A new translation by Victor H. Mair

Offline k-hat

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Sounds really iffy.  If it's primo superclean you may can get away with it, but i would back it.  deep and dark heat treat like has been said, and i'd go a full 2" or more on the width of the working limb.  Can you shorten the handle area to add working limb?  I'd also find a short draw anchor point and measure your draw and use that for your goal draw length.

for what it's worth.  It'd be cool to see just how much hb can take.

Offline Pat B

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I've built a few 60"t/t static recurves with 6" to 8" of static tips. They were either osage or elm. I use a bulbous handle and bring the bend back into the handle right at full draw. I've tillered these bows to 28"(my draw is 26") and in weights from 55# to over 60#. The trick is to get the inside limbs bending right up to the handle at full draw or through the handle. This will add another 6" to 8" to the working portion of the bow.
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline JonW

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As Pat commented, I also have pulled off 60" statics in Elm. I did an Osage at 57". Make it bend right up to the handle and you'll be alright.

blackhawk

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2 1/2" min width and run that width to a foot before any taper...heck id even start a tad wider and see how it responds as you tiller it down and how much mass it is weighing before reducing any of the width.

Offline okie64

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Im anxious to see how this one turns out. Ive built a few hackberries and have always been impressed by it. I always give mine a good heat-treating.

Offline toomanyknots

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Im anxious to see how this one turns out. Ive built a few hackberries and have always been impressed by it. I always give mine a good heat-treating.

I still haven't strung for a heat gun. I just never liked the burnt look of a heat treated bow, but I guess a bow with a burnt belly and 0 string follow is alot prettier than a bow with a clean belly and 3" + set, which is what I am guessing I am gonna get with this guy. I recently re-read Marc st.louis's chapter on heat treating in tbb, and I figure I might get me a similar jig going on some time in the future, I know I should anyway. I got a couple bows like this in the works for some reason. I wanna linen back it, but I know it will just take more set and shoot slower if I do. If I sinew backed some reflex into it, and kept the weight lower, I am sure I would be all kinds of fine, but I would rather keep it unbacked. I was thinking I might tiller it out to 20", and if it's got like 2" set already, as un-heat treated hackberry tends to do in designs like this, I might say screw it, or just sinew some reflex into it if I got the sinew. More likely than anything though, I will probably just floor tiller, and then go buy a heat gun and heat try my hands at heat treating and then go from there, as has been suggested a couple times,  ;D. Thank you for the advice yall.
"The way of heaven is like the bending of a bow-
 the upper part is pressed down,
 the lower part is raised up,
 the part that has too much is reduced,
 the part that has too little is increased."

- Tao Te Ching, 77, A new translation by Victor H. Mair

Offline k-hat

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Got an inexpensive wagner heat gun from depot for cheap (like $15 bucks).  Hi and low settings, works great.  You wouldn't believe how many hours of run time mine has had!!  I use it to warm my garage and myself sometimes while i work in the cold ::)

Go get one, you won't be dissappointed.  And you don't have to burn the belly to give it a good tempering.  I find with whitewoods, low and slow heat over a form (i basically temper in my reflex) will give a huge payback.  Chocolate color looks nice too.

Offline Pat B

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There is a build along of the 60" elm static recurve I built at the top of the "Archives" thread. Check it out.
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline okie64

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If you dont want to buy a heatgun you can do the same thing over your kitchen stove with the bow reverse braced or you can do it over hot coals. Ive done all three methods but I still like the heat gun over a form the best.

Offline toomanyknots

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Heres the bow to be,... maybe,...







The width at the fades start at 2 3/8", and end at 1 5/8" where the recurves start. The handle is about 10" when counting the fades, which hopefully I will be able to turn some of that into working limb, but for now it is 10" of non-working limb.

There is a build along of the 60" elm static recurve I built at the top of the "Archives" thread. Check it out.

Thanks for bringing that to my attention, I will definitely check it out, thanks.

Got an inexpensive wagner heat gun from depot for cheap (like $15 bucks).  Hi and low settings, works great.  You wouldn't believe how many hours of run time mine has had!!  I use it to warm my garage and myself sometimes while i work in the cold ::)

Go get one, you won't be dissappointed.  And you don't have to burn the belly to give it a good tempering.  I find with whitewoods, low and slow heat over a form (i basically temper in my reflex) will give a huge payback.  Chocolate color looks nice too.

15 bucks sounds nice and cheap, thanks, I will be sure to pick one up next time I get the chance.

If you dont want to buy a heatgun you can do the same thing over your kitchen stove with the bow reverse braced or you can do it over hot coals. Ive done all three methods but I still like the heat gun over a form the best.

I've used my stove to heat treat a couple years ago. I heat treated one of the first real bows I made on my stove. Well I have made others when I was younger, but the first one I made in my later life. All the ones I made when I was a kid where probably too pathetic to be called bows anyway,  ;D. The bow that I heat treated over my stove was a really short bow, made from an osage limb. Sapwood back and a heartwood belly, and I sinew backed it too, which was my first sinew backing as well. First time I made hideglue too. The sinew backing made the tiller go off and one limb much more stronger than the other, but I said screw it and shot it anyhow,  >:D. That was the first bow I ever finished either, I mean gave a nice finish. I should a kept the ugly thing, but I think I wanted the sinew off the back for something if I recall...
« Last Edit: January 04, 2013, 06:26:32 pm by toomanyknots »
"The way of heaven is like the bending of a bow-
 the upper part is pressed down,
 the lower part is raised up,
 the part that has too much is reduced,
 the part that has too little is increased."

- Tao Te Ching, 77, A new translation by Victor H. Mair

Offline JonW

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I have used pine resin while heat treating a few times like Marc shows. It seemed to keep the wood from turning an undesireable color in my experiences.