Tillering the Bamboo/Osage Blank
Total Page:16
File Type:pdf, Size:1020Kb
www.bowyersedge.com [email protected] 7425 Fontanelle Road Ostrander, OH 43061 740.666.2861 Tillering the Bamboo/Osage Blank o get the most out of the blank you’ve purchased from Next, unless you the Bowyer’s Edge™, I’ve included these step-by-step purchased your stave from Tinstructions based upon the faceted approach to tillering. The the Bowyer’s Edge, in method illustrated and described here is similar to the method in which case the following Hunting the Osage Bow, page 96. The facets on the bamboo-backed conditions are already met, bow are of different proportions, and I have simplified their make certain that the sides lettering and numbering, but they still correspond to the facets in of the handle are square HOB. These instructions also apply to any blank, straight-limbed or to the belly and flush reflex/deflex, that has been assembled and squared up according with the bamboo., Rasp to the dimensions and directions provided in the video, Hunting perpendicular to the belly the Bamboo-Backed Bow. until the bamboo glue line In preparation to tackling your blank, I’d urge you to reread the disappears along the length tillering sections in Chpts. 7 and 8. Review faceting, floor tillering, of the handle. Make sure teaching the bow to bend, centering the string, and fingerprinting the curves in the bulbous handle flow smoothly along the neck of the bow at full draw. Chapter 3 (the selection and use of the bow and then flare out evenly, symmetrical from both sides. Nicholson rasps, nos. 49 and 50) and Chapter 4 (the sharpening of Photo 1 shows the handle before and after the osage is worked to cabinet scrapers) will provide you the tool foundation required to the bamboo outline. Your Bowyer’s Edge blank already resembles shape your blank. These are subjects that we could not cover in a the “after” photo, and the bamboo, if you refer to the video, is an 70 minute video, but that are important to your tillering success, accurate and precise outline of the bow. supplementing the information in this pamphlet and providing you Upon completion, go to the belly side of the handle. Determine a broader perspective. the final depth of the handle, depending upon whether you prefer Faceting will help you control the tillering process, and the a deep, oval bulbous handle following directions will lead to a bow featuring a trapezoidal or a shallower, rounder limb cross section. A reflex/deflex bow owes its efficiency to the one. Thickness the handle relatively small section of working limb it employs, as compared to your preference, back to to the full working limb of the straight-end bamboo blank or the belly. Work from the crown classical flatbow described in HOB. The r/d design places greater of the handle down the dips. stress upon the belly of the bow, and the trapezoidal cross section Keep this convex portion helps relieve that stress by moving the neutral axis toward the of the handle square with belly and thereby shifting the workload to the stronger bamboo flowing lines until you back. A trapezoidal cross section also works to relieve stresses arrive at a desirable depth and prolong the life of a straight-limbed bow. Of course, other for the handle. paths beyond the one outlined here will lead you to a successful After that, work the bow. Choose any method or limb cross-section with which you concave portion, from are comfortable. Enough theory. Let’s remove some wood. the dips back up into the handle, thinning the joint across the width of the limb where the The first objective is to square up the bow everywhere, riser handle feathers into the limb, as shown in Photo 2. Be careful limbs and handle. The bamboo blank you purchased already has not to dig into the limb at the end of this joint or you will hinge the bow. accomplished this step, though the limb outline along the osage Working from the glue line at the end of the riser up into the dips, overhang will probably require some further attention. Notice that rather than down the dips and into the limbs will help you avoid the osage is sawed outside of the bamboo for most of the limb dishing the limb. length, forming a ledge. This is by design, to facilitate laying in the The result should be a clean, gentle outline flowing from the trapezoidal cross section. Lay the flat of your rasp along the band limbs into the feathered riser up through the concave dips and saw marks on the limb and work the rasp like a plane, removing into the convex handle. Once your bow is everywhere squared saw marks and any dips or humps due to inaccurate bandsawing. up, symmetrical and flowing in its outlines, belly to back and from Leave mirror amounts of osage to hang out on both sides of the both sides, you are ready to facet. limb on both upper and lower limbs. Keep the sides square to the The first facet to establish travels the length of both limbs belly of the bow. Notice that the osage overhang disappears as it and blends the bamboo into the osage overhang. It requires that tapers into the nock ends. The tip area of the limb approaching the you rasp back into the bamboo a little. Do this with long sweeping nocks need not be “trapped”, but it does come to you wider than strokes of your rasp and work to the glue line along the whole it needs to be so that you can make string corrections later on in length of the limb a small, uniform depth at a time, as shown in Photo case the string runs to one side or the other of the handle. 3, rather than by sections It’s a choice that does not all at once. The glue line affect performance or where the bamboo meets longevity, but there are the osage is the reference two important points to point for the sloping sides observe. You must scrape of the trapezoid. Rasp or sand all of the rind, even approximately at 60º until if you do not remove all of you arrive at the glue line it, because the waxy outer so that the glue squeeze surface otherwise will not between the bamboo and hold a good finish. When the slat and the overhanging you scrape, move your tool from an unworked area into ledge of the slat disappears. Photo 4 shows the size a scraped area, and lift the of the facet with enough of the glue squeeze still remaining to tool at the end of your sweep. Work as though you were painting reveal an exaggerated glue line, indicating that the facet is very down the length of the limb: begin the stroke in an unpainted area, close to completion. A sliding T-bevel laying near the facet shows and lift the bristles in a gentle sweep as you enter the painted area. the correct angle. The bamboo and the osage should form one This technique will remove the tiny bite marks in the surface of plane once the ledge is removed and the glue line is thin. The facet the bamboo that begin each stroke. should travel along the top 1/3rd of the osage. This facet is labeled Let’s tend to handle facets A, and the transition area into limb “B”. facets A. Rasp in handle Now to the belly. These facet A as shown in Photo are shallow facets by 7. As you rasp down the comparison. You can see dips, notice how the angle the pencil line on Photo 4 changes as you transition where this facet belongs as from the handle through seen from the side, a little the dips into the limb. See less than a third of the way the comparison in photos up from the belly. It is facet 8 and 9. The handle facet “A”. Once you establish is much more angular than belly facets “A”, you will the shallow limb facet. You have remaining a strip of must move the handle osage down each limb from of your rasp toward the the original sides of the belly as you work from the bow, about 1/4th to 1/3rd the handle into the limb. It’s not difficult; it’s just a matter of blending thickness of the osage. This is what remains of the facet you planed the facets into one another in this transition area. flat with your rasp when you squared up your limbs and evened After you have negotiated this maneuver, it is time to blend the overhang between them, and it is labeled with the number “1”. a few facets into one another. Start with facets A and 3 as seen Note in the pictures that although facets are roughed in with in photo 10. Photo 11 shows this blending accomplished on the a #49 or #50 Nicholson upper limb, so that the end rasp, they are cleaned off of the riser handle feathers afterwards with a Bowyer’s into the limb in a subtle arc Edge or a scraper. You can that reflects the radius on also use a smooth 12” file the belly of the bow. Notice or a block of very coarse that the lower limb has not sandpaper, around 60 grit. been radiused yet, that the Seen from the belly end of the riser is still at side in Photo 5, these right angles to the limb on shallow facets, labeled “A”, facet 3.