A working recurve is easier to construct and more suitable for a bowyer's first efforts.
A working recurve's tips bend, or uncoil, so they can be about the same thickness as a longbow's. 1 normally floor-tiller a bow to be recurved in this way, or even string it and roughly tiller it at half draw. This allow the tips to be as thin as possible before they are heated and bent, an important point to be remembered during all phases of wood bending. The thinner a piece of wood, the less heating time required to bend it, and the less the wood will be disrupted and weakened.
It is a smart idea to leave the tips wide during the bending process. This helps them bend only in one plane, at right angles to the limb, instead of twisting to one side. After they are shaped they are narrowed to the final desired width.
A working recurve bent by hand using direct heat.
The simplest way to construct working recurves is with direct heat. Though an open flame can be used, I prefer a propane grill since it traps the heat and allows it to soak into the wood more slowly. Remove the metal grillwork from the propane grill, as it can scorch lines across the bow's tip, creating a hamburger patty appearance. Set the temperature on low. Keep in mind that when wood is heated slowly, so that it is the same temperature throughout instead of hot on the outside and cool on the inside, the bend is more stable and enduring. 1 coat the section of the bow to be bent with grease of some sort; bacon grease or any type of fat will work, but canned shortening is the easiest. This helps keep the wood from scorching while aiding in the penetration of heat, and also traps inherent moisture in the wood rather than allowing it to be forced out, rendering the wood dry and brittle.
Heat only the section of the limb to be bent, in this case the tips. There is no need to heat-stress wood which will not be bent. After placing the tip of the bow in the grill, turn it occasionally, every minute or so, then check it after a couple of minutes to see if it is hot enough to bend. If it isn't hot enough, and it probably won't be, return it to the grill for additional heat. Continue regularly checking the flexibility of the wood; you want it just hot enough to bend and no more. Remember, the less heat used, the better. Also, watch closely for any scorching or darkening of the tip. If this occurs, and the wood still won't bend, either the heat is set too high or the wood is too thick.
When the wood is pliable, bend it with potholders or towels to avoid burning the hands. Hold the tip in the bent position for a minute or two, after that it will usually hold its shape until completely cool. At least this is true for Osage orange. It seems a bit of a paradox that the woods normally the most contrary to work, such as Osage and yew, are among the easiest to bend. Hickory, though it grows straight and fairly knot-free, is more difficult to bend with direct heat than Osage. A wood which proves obstinate can be boiled or steamed, which will be discussed under static recurves.
There is no reason a form cannot be used to clamp the bow tip once it is heated and pliable. But I have found it easier to make the mild bends by hand. Once one tip is bent satisfactorily, the other should be heated and shaped to match. After both are turned, one end can be re-heated, if necessary, so that the tips will be identical. If steam or boiling is used, then the bow must be clamped to a form to hold its shape until dry and cool. Or the bend can be held under cold water for several minutes.
Be aware that with a self bow unbacked with sinew, some of the recurve may pull out after a number of shots. The only way to insure that the bend remains entirely intact in a working recurve is to sinew-back the bow.
A fine example of a reflex-deflex design, a yew self bow made by Tim Baker. This bow is a dead ringer for a four thousand year old bow found in Italy.
Perhaps the most efficient, and accurate, working recurve design is the reflex-deflex, similar to one of the Bear Kodiak™ fiberglass laminates. The recurves add speed while the deflex maintains high stability and accuracy. One way to attain this shape is to boil a length of wood, without a thickened handle section, then clamp it to an appropriate form. In fact, a stave could no doubt be heated and placed in a fiberglass bow press. When cool, glue a handle section to the stave and, if desired, add a layer of sinew to the back of the bow. An alternative is to splice together two billets with a bit of deflex built in, then recurve the tips. Fred Bear spent a lifetime developing and perfecting this design in a fiberglass bow, and it is an excellent model for all-wood or wood and sinew working recurves.
STATIC RECURVE
The tips of this design are thick enough so they do not bend when the bow is drawn. These static ends keep the angle of the string in relation to the tips low at full draw and provide a smooth draw, but place more strain upon the shorter working section of the limb. Though very efficient, it is difficult and time consuming to make.
An excellent design; an angular bend of about 60 degrees at the tip.
My favorite design for this type of bow, for a 28" draw length, is made from Osage, 63" long, about 1 3/4" - 2" wide at the widest section of the limb, and sinew-backed. The "ears," or stiff tips of the bow, are 4" long and bend fairly sharply at about a 60 degree angle. These tips are made narrow and just thick enough not to bend, which helps save mass and add speed. My personal preference is a weight of about 55 pounds, which shoots a hunting weight arrow at around 170 fps.
Since the tips of this bow design are thicker than a working recurve's, so they won't bend, they must be heated with steam or boiling water. Thirty minutes of heating for each half inch of wood thickness is a useful rule of thumb. Some type of support for the belly of the bow is a necessity, as bending the limb
The static tip remains stiff throughout the draw. Note the design; tip was formed around a smooth arc.
Backward into a recurve will pull up splinters on the belly without it. This is equivalent to drawing a bow which has the growth rings on the back badly violated. A strap of band metal, such as a used bandsaw blade as wide as the end of the bow, will hold down splinters and handle the problem. Clamp one
Apparatus for recurving tips. The very end of the bow is secured to the form with two "C" damps. After boiling in a large kettle for twenty minutes the pipe clamp is added and tightened to the degree shown, then the entire device returned to the kettle for more boiling. Note strap of metal around outside of bend, held at the tip by the first clamps holding the end of the bow. The other end of the strap is held by a single clamp along with a block of wood to protect the back of the bow, both placed far enough up the limb to clear the form as the bend progresses.
After boiling for about fifty minutes, the bend is nearly complete. Each time the bow is removed from the kettle the clamps are only tightened until snug, then the tip returned for ten minutes more boiling. When the bend is complete, the bow is left clamped to the form for twenty-four hours. The finished bow is pictured on the front cover.
End of the metal to the form along with the tip, then clamp it further up the limb with shims to protect the wood. As the wood is heated, the strap automatically pulls tighter and tighter as the wood is bent farther. It acts much like the backing of a bow, exerting tension to hold down splinters. Keep in mind that tips which are of uniform thickness are less likely to crack and will bend more evenly.
Ron Hardcastle’s method for securing tip of bow and metal strap to the form.
Recurving jig devised by Tim Baker. The long wedge is jammed crossways in the slot to hold the bow's tip. As explained in the text, Baker rarely uses a metal strap to support the belly of the bow, but, if desired, one could no doubt be secured by the ivedge at the same time as the tip.
A bending method which has worked well for me is to clamp the bow tip and metal strap to the form, place them in a pot of cool water, then apply heat until the water boils. Raising the temperature of the wood along with the water, rather than plunging cold wood into boiling water, decreases the chances of cracks along the radial grain. Once the water begins boiling, occasionally raise the contraption from the container, tighten the clamps until they are snug, then immediately return it to the water for more boiling. Every ten minutes or so tighten the clamps further, using potholders to protect the hands from the hot metal, until the tip is shaped around the form. Pipe clamps work very well for this if you have a pot large enough to submerge the entire device. 1 use an old cast-iron pot, which holds about fifteen gallons of water, suspended by a tripod over a firepit, but a large pot on a stovetop works as well.
Malcolm Smith's ingenious metal strap attachment. The bolts are tightened to secure the clamp to a billet near the handle, then the hook of the turnbuckle (whose opposite end is attached to the end of the strap) goes through the eye-bolt.
Malcolm Smith has a slightly different technique. He boils the bow tip, with supporting metal strap in place but without the form, for about two hours. This long heated period is necessary because Malcolm bends a relatively thick piece of wood for the tips of his bows. When ready, he removes the wood from the water and immediately clamps the tip, along with the supporting metal strap, to the form. Working quickly so the wood will not have time to cool, he tightens a turnbuckle to snug the strap (a notable refinement to his system), then pushes the limb down to the form, achieving all of the bend at once. He leaves the wood clamped to the form until cool. (The old-time method also involved constantly pouring boiling water over the wood as it was placed in the form and bent. This prevented the outside of the wood, which must do the most bending, from cooling off until the bend was made).
Smith's bending jig with clamps in place.
After extensive boiling, the tip of the bow, along with the strap, is clamped to the form, the turn-buckle on the metal strap quickly tightened, then...
...all of the bend is achieved at once
The bow is clamped to the form and the billets (in this case) are set aside until cool and dry.
With seasoned and dry wood, Malcolm soaks the portion to be bent for several days prior to boiling to saturate the outside pores with water, which is an excellent strategy. He feels this eases the bending process with less danger of cracking. On a related subject, it is much easier to bend relatively green wood (12 to 20 percent moisture content) than completely dry wood (seven to ten percent moisture content). A good approach might be to bend wood into recurves when it is still between 12% and 20% moisture content, then air dry it as you normally would before finishing the bow.
Chuck Boelter, a dentist by profession (though he should have been a brain surgeon judging by his static recurves), has yet another method. He prefers to steam the wood, rather than boil it, believing this to be a faster, easier method. He steams the tip at least thirty minutes, or more for drier wood. Chuck, too, uses a metal strap around the belly side to prevent splinters from lifting up, then
Chuck Boelter shooting one of his static recurves.
Places the tip in a form and achieves all of the bend at once. When the bend is achieved, he places the tip, along with the form and clamps, in cold water for 15 minutes, then removes and allows it to dry for 24 hours.
It is possible to produce a static recurve without a form — and even without the supporting metal strap around the belly — with a method Tim Baker has devised. He works the belly of the bow to one growth ring, as well as the back, boils the tip until pliable, then, using potholders to protect the hands, he bends the tip over a knee, then plunges the recurve under cold tap water until it cools. By working the belly to one growth ring, the yearly layers of wood do not try to pull apart when bent and a severe recurve can be introduced. This technique of working the belly prior to bending can also be employed with a form.
No matter which method is used, once both tips are bent it is a good idea to let the wood dry for several days, depending on local conditions, before attempting to bend or string the bow.
A word about bracing a recurve. If you normally place the lower tip against the instep of the left foot, then pull on the handle with the left hand while pushing down on the upper tip with the right and slipping the string into place in the nocks, then two grievous events can take place if a recurve slips in the grip. First, a loss of control during stringing can cause one or both tips to twist, which can result in a dead bow when a tip breaks off. I once shattered all existing records for sustained cursing, freestyle division, when during bracing my hand slipped and I broke the upper tip from a new bow I had been working on for three weeks. It was not a sight for women and children. But an even worse calamity can strike if a recurved bow slips using normal stringing methods. If the bow slips from your grip, the highly-stressed upper limb will fly forward, and the tip is aligned precisely to strike the end of your nose at Mach 2. This is no small matter, as the tip can permanently remove teeth and/or eyeballs in an instant. With a recurve, a much safer stringing method is to "step-through" the bow, which allows more control and less chance of injury to bow and bowyer. A commercial bow-stringer, which fits over the bow tips, also works well.
Normally, if a bow is to be sinew-backed, I never pull it until the sinew is in place. But this is not the case with a sinew-backed static recurve. A bow of this design must be tillered so that it can be strung to judge the alignment of the tips. Fashion string grooves on the belly side of the recurves with a chainsaw file before the first stringing, as this helps the string "track" properly. But quite often (read usually), when first strung, the bow will still twist slightly and the tips will not track as they should. The cure for this is to mark the tip which seems to be out of alignment with the direction it needs to be bent to correct the twist. Sometimes both tips require adjustment. Then unstring the bow, coat the tip with grease, and heat with direct heat to bend it. When it has cooled completely, restring the bow and check the alignment again. It may well still be incorrect. Sometimes the tips must be heated and bent four or five times before the string alignment around the recurves is satisfactory.
I have always performed this heating and adjusting of the tips before the sinew was applied, feeling the heat might damage or destroy the backing. This is one situation where a sinew-backed bow is tillered, at least enough to allow it to be strung, before the backing is in place, though even a static recurve should not be drawn until backed. Chuck Boelter, however, backs his bows before lining up the ears. After the sinew cures, he strings the bow to determine which direction to bend the ears, then unstrings it and gently heats the belly side only over an electric burner. He recommends rounding off the wood's edges on the belly side, as sharp corners are more likely to scorch. When the wood is hot enough to bend, the sinew will just be warm and unaffected. He clamps the tip until cool, then restrings the bow. The tips will often have to be reheated several times before alignment is perfect, and the adjustments during heating are quite subtle. He notes that shorter bows seem easier to straighten and that leaving the tips a bit wide at this stage is also a good idea.
Whether sinew-backed or not, be aware that wood with twists or other abnormalities will sometimes look fine when unstrung, but when strung the tips will be twisted. By the time they are finally bent properly, the tips may look badly out of kilter when the bow is unstrung. This is unimportant. All that matters is how the string tracks around the recurves when the bow is braced.
There is a useful refinement to the sinew-backing of a static recurve. Since the tips are thick enough not to bend, and are in no danger of breaking, the sinew need only go to the base of the recurves if you wish. This saves on weight at the tips, since sinew and glue weigh about twice as much as wood. The area where the sinew feathers out at the base of the recurves should be wrapped with sinew for security, to prevent it from pulling loose and possibly causing the bow to break.
One of Boelter’s recurves, showing thin glue line where extra piece of wood was added to stiffen the tip. Two things are noteioorthy. First, the tip is thickest, and strongest, right at the bend where the greatest leverage is exerted, then becomes thinner toward the tip to reduce weight. Second, the dark wrapping secures the end of the sinew-back, as the backing only reaches the base of the recurve and does not go over the tip.
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