{"id":505,"date":"2023-12-12T00:20:07","date_gmt":"2023-12-12T00:20:07","guid":{"rendered":"https:\/\/artchery.org\/wordpress\/?page_id=505"},"modified":"2024-09-28T18:56:42","modified_gmt":"2024-09-28T18:56:42","slug":"material-science-in-yamishis-art","status":"publish","type":"page","link":"https:\/\/artchery.org\/wordpress\/index.php\/material-science-in-yamishis-art\/","title":{"rendered":"Material Science in Yamishi&#8217;s Art"},"content":{"rendered":"\t\t<div data-elementor-type=\"wp-page\" data-elementor-id=\"505\" class=\"elementor elementor-505\">\n\t\t\t\t\t\t\t<div class=\"elementor-element elementor-element-3b2c843 e-flex e-con-boxed e-con e-parent\" data-id=\"3b2c843\" data-element_type=\"container\" data-settings=\"{&quot;background_background&quot;:&quot;classic&quot;,&quot;content_width&quot;:&quot;boxed&quot;}\" data-core-v316-plus=\"true\">\n\t\t\t\t\t<div class=\"e-con-inner\">\n\t\t\t\t<div class=\"elementor-element elementor-element-3b68fb4f elementor-widget elementor-widget-heading\" data-id=\"3b68fb4f\" data-element_type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t<style>\/*! elementor - v3.18.0 - 08-12-2023 *\/\n.elementor-heading-title{padding:0;margin:0;line-height:1}.elementor-widget-heading .elementor-heading-title[class*=elementor-size-]>a{color:inherit;font-size:inherit;line-height:inherit}.elementor-widget-heading .elementor-heading-title.elementor-size-small{font-size:15px}.elementor-widget-heading .elementor-heading-title.elementor-size-medium{font-size:19px}.elementor-widget-heading .elementor-heading-title.elementor-size-large{font-size:29px}.elementor-widget-heading .elementor-heading-title.elementor-size-xl{font-size:39px}.elementor-widget-heading .elementor-heading-title.elementor-size-xxl{font-size:59px}<\/style><h2 class=\"elementor-heading-title elementor-size-default\">Traditional aesthetics and material science <br> merge in the yamishi\u2019s art<\/h2>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t<div class=\"elementor-element elementor-element-f7a76af e-flex e-con-boxed e-con e-parent\" data-id=\"f7a76af\" data-element_type=\"container\" data-settings=\"{&quot;content_width&quot;:&quot;boxed&quot;}\" data-core-v316-plus=\"true\">\n\t\t\t\t\t<div class=\"e-con-inner\">\n\t\t\t\t<div class=\"elementor-element elementor-element-7174a94 elementor-widget elementor-widget-text-editor\" data-id=\"7174a94\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t<style>\/*! elementor - v3.18.0 - 08-12-2023 *\/\n.elementor-widget-text-editor.elementor-drop-cap-view-stacked .elementor-drop-cap{background-color:#69727d;color:#fff}.elementor-widget-text-editor.elementor-drop-cap-view-framed .elementor-drop-cap{color:#69727d;border:3px solid;background-color:transparent}.elementor-widget-text-editor:not(.elementor-drop-cap-view-default) .elementor-drop-cap{margin-top:8px}.elementor-widget-text-editor:not(.elementor-drop-cap-view-default) .elementor-drop-cap-letter{width:1em;height:1em}.elementor-widget-text-editor .elementor-drop-cap{float:left;text-align:center;line-height:1;font-size:50px}.elementor-widget-text-editor .elementor-drop-cap-letter{display:inline-block}<\/style>\t\t\t\t<p><strong>High end take-ya, made from single stalks of Yadake bamboo according to ancient traditions, are beautiful and compelling to many kyudoka. However, they tend to warp with changes in temperature and humidity, and their strong circumferential stresses may lead to lengthwise splits. In contrast, Ya made out of modern materials, such as aluminum and carbon, have very uniform properties and are minimally influenced by temperature and humidity. The laminated bamboo ya, whose fabrication is described here, combines uniformity and stability of ya made of modern materials with the aesthetics of traditional single stalk take-ya.<\/strong><\/p>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-3c17447 elementor-widget elementor-widget-heading\" data-id=\"3c17447\" data-element_type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t<h4 class=\"elementor-heading-title elementor-size-default\">The excellence and vulnerabilities of take-ya<\/h4>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-bf364bb elementor-widget elementor-widget-text-editor\" data-id=\"bf364bb\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<p>As explained above, ya made out of aluminum or carbon are convenient and practical, but many kyudoka appreciate the aesthetics of bamboo take-ya.\u00a0 Bamboo take-ya do compare favorably with western archery arrows made from natural materials. For instance, my sensei, Aaron Blackwell, allowed me to examine and measure his Shinsa ya. They are 110\u00a0 cm long and weigh 35 g.\u00a0 Suppose we make a ya out of Port Orford cedar, a premium material for western archery arrows.\u00a0 To achieve the same stiffness as the Shinsa ya, it must have a larger diameter and would weigh 50 g. This comparison points to the spectacular capabilities of bamboo.\u00a0 We return to the vulnerabilities.<\/p><ul><li>As a bamboo stalk dries out from the initially green state, strong circumferential stresses develop.\u00a0 Most owners of traditional take-ya are very familiar with repairing lengthwise splits.<\/li><li>Even if the take-ya does not split, the stresses are still there, resulting in\u00a0 warping with changes in temperature and humidity.\u00a0<\/li><li>The excellent craftsmanship of a traditional yamishi can produce a uniform cylindrical outer surface of the ya.\u00a0 Inside, biology rules;\u00a0 the interior void is generally not uniform between nodes.<\/li><\/ul>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-bf1437a elementor-widget elementor-widget-heading\" data-id=\"bf1437a\" data-element_type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t<h4 class=\"elementor-heading-title elementor-size-default\">Laminated bamboo ya<\/h4>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-9dffb8a elementor-widget elementor-widget-text-editor\" data-id=\"9dffb8a\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<p>Perhaps we can take a hint from the yumishi:\u00a0 With their thin bamboo back and belly laminations,\u00a0 and cores with seven or more strips of bamboo and hardwood, taki-yumi are advanced far beyond single staves.\u00a0 Why not\u00a0 laminate ya from multiple bamboo strips?\u00a0 Traditional fly fishing rod craftsmen do something like this.<\/p>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t<div class=\"elementor-element elementor-element-5f5daab e-flex e-con-boxed e-con e-parent\" data-id=\"5f5daab\" data-element_type=\"container\" data-settings=\"{&quot;content_width&quot;:&quot;boxed&quot;}\" data-core-v316-plus=\"true\">\n\t\t\t\t\t<div class=\"e-con-inner\">\n\t\t\t\t<div class=\"elementor-element elementor-element-d7f9ccb elementor-widget elementor-widget-image\" data-id=\"d7f9ccb\" data-element_type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t<style>\/*! elementor - v3.18.0 - 08-12-2023 *\/\n.elementor-widget-image{text-align:center}.elementor-widget-image a{display:inline-block}.elementor-widget-image a img[src$=\".svg\"]{width:48px}.elementor-widget-image img{vertical-align:middle;display:inline-block}<\/style>\t\t\t\t\t\t\t\t\t<figure class=\"wp-caption\">\n\t\t\t\t\t\t\t\t\t\t<img fetchpriority=\"high\" decoding=\"async\" width=\"768\" height=\"385\" src=\"https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2024\/03\/hexagon1-768x385.jpg\" class=\"attachment-medium_large size-medium_large wp-image-1212\" alt=\"\" srcset=\"https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2024\/03\/hexagon1-768x385.jpg 768w, https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2024\/03\/hexagon1-300x150.jpg 300w, https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2024\/03\/hexagon1-1024x513.jpg 1024w, https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2024\/03\/hexagon1.jpg 1192w\" sizes=\"(max-width: 768px) 100vw, 768px\" \/>\t\t\t\t\t\t\t\t\t\t\t<figcaption class=\"widget-image-caption wp-caption-text\">Fig. 1:  (a)  Cross section of laminated fly fishing rod.  (b)  The laminations are truncated into trapezoids, resulting in a hollow rod.   The arrows represent forces acting on the top strip, when we wrap a chord tightly around the rod.  The arrow a and b act on the glue lines.  Their vector sum a+b is illustrated in panel (c).   The top of the strip is pressed by the opposite and equal force -(a+b).<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-69e7cd9 elementor-widget elementor-widget-text-editor\" data-id=\"69e7cd9\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<div class=\"page\" title=\"Page 2\"><div class=\"layoutArea\"><div class=\"column\"><p>Figure 1a depicts the cross section of a laminated fly rod.\u00a0 Most of the rod&#8217;s stiffness and strength come from the strong bamboo layers near the surface.\u00a0\u00a0 In Fig. 1b, we imagine cross sections of the individual strips truncated into trapezoids.\u00a0 We would have a hollow rod with most of the stiffness and strength of the solid rod.\u00a0\u00a0 The trick is the layup.\u00a0 As any woodshop person knows, uncured glue lubricates the contacts between joined pieces.\u00a0 Controlling the proposed assembly looks like a nightmare.\u00a0<\/p><p>Simple physics comes to the rescue.\u00a0 A yumishi might think to tightly wrap a chord around the outer surface in a helix.\u00a0 That is what he does with yumi.\u00a0 He would be in luck because the forces act in his favor.\u00a0 An individual strip feels compression acting on the two glue lines.\u00a0 These compressions by themselves tend to force the strip away from the center, but the tight wrapping of the chord around the perimeter prevents this.\u00a0 The caption in Fig. 1 explains the balance of forces in a bit more detail.<\/p><p>In practice, there are additional workshop tricks, such as how to start the assembly process. A process\u00a0 emerges just by engaging and &#8220;thinking with your hands.&#8221; Starting from a cured hexagonal rod, the final cylindrical surface of the ya is produced by sanding away the vertices.\u00a0 Left panel of Fig. 2 depicts the cross section of ya that results. If we have more strips, the polygon perimeter of the cross section before rounding is closer to a circle. Right panel of Fig. 2 depicts a cross section with twelve strips.\u00a0<\/p><\/div><\/div><\/div>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t<div class=\"elementor-element elementor-element-3778c96 e-flex e-con-boxed e-con e-parent\" data-id=\"3778c96\" data-element_type=\"container\" data-settings=\"{&quot;content_width&quot;:&quot;boxed&quot;}\" data-core-v316-plus=\"true\">\n\t\t\t\t\t<div class=\"e-con-inner\">\n\t\t\t\t<div class=\"elementor-element elementor-element-f7614a7 elementor-widget elementor-widget-image\" data-id=\"f7614a7\" data-element_type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t<figure class=\"wp-caption\">\n\t\t\t\t\t\t\t\t\t\t<img decoding=\"async\" width=\"768\" height=\"304\" src=\"https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2024\/09\/cross-sections-768x304.jpg\" class=\"attachment-medium_large size-medium_large wp-image-2574\" alt=\"\" srcset=\"https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2024\/09\/cross-sections-768x304.jpg 768w, https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2024\/09\/cross-sections-300x119.jpg 300w, https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2024\/09\/cross-sections-1024x406.jpg 1024w, https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2024\/09\/cross-sections.jpg 1262w\" sizes=\"(max-width: 768px) 100vw, 768px\" \/>\t\t\t\t\t\t\t\t\t\t\t<figcaption class=\"widget-image-caption wp-caption-text\">Fig. 2:  Cross sections of laminated bamboo ya. Left: Hexagonal laminated ya. Right: Twelve-sided laminated ya. It is much closer to a cylinder than the heaxagon.<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t<div class=\"elementor-element elementor-element-aaf04b4 e-flex e-con-boxed e-con e-parent\" data-id=\"aaf04b4\" data-element_type=\"container\" data-settings=\"{&quot;content_width&quot;:&quot;boxed&quot;}\" data-core-v316-plus=\"true\">\n\t\t\t\t\t<div class=\"e-con-inner\">\n\t\t\t\t<div class=\"elementor-element elementor-element-bd5b852 elementor-widget elementor-widget-text-editor\" data-id=\"bd5b852\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<p>Figure 3 depicts the trapezoidal cross section of one strip in the twelve strip lamination and a closeup of two adjacent strips joined together.\u00a0 For a ya with an outer diameter of, say, 9.1 mm, the width of the strip is l \u2248 2.44 mm. A thickness close to \u03c4 \u2248 0.8 mm produces a ya whose weight is close to a traditional take-ya with the same outer diameter.\u00a0 The geometry of the twelve strip cross section in Fig. 2 implies a 30<sup>o<\/sup> angle between the surfaces of two adjacent strips, as depicted in the\u00a0 second panel of Fig. 3.\u00a0 The 30<sup>o<\/sup> angle is achieved if the sides of a single strip have the 15<sup>o<\/sup> angles as in the first panel of Fig. 3.<\/p>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t<div class=\"elementor-element elementor-element-5b377f3 e-flex e-con-boxed e-con e-parent\" data-id=\"5b377f3\" data-element_type=\"container\" data-settings=\"{&quot;content_width&quot;:&quot;boxed&quot;}\" data-core-v316-plus=\"true\">\n\t\t\t\t\t<div class=\"e-con-inner\">\n\t\t\t\t<div class=\"elementor-element elementor-element-5c0d2bd elementor-widget elementor-widget-image\" data-id=\"5c0d2bd\" data-element_type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t<figure class=\"wp-caption\">\n\t\t\t\t\t\t\t\t\t\t<img decoding=\"async\" width=\"768\" height=\"194\" src=\"https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2024\/03\/trap-768x194.jpg\" class=\"attachment-medium_large size-medium_large wp-image-1232\" alt=\"\" srcset=\"https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2024\/03\/trap-768x194.jpg 768w, https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2024\/03\/trap-300x76.jpg 300w, https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2024\/03\/trap-1024x258.jpg 1024w, https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2024\/03\/trap-1536x387.jpg 1536w, https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2024\/03\/trap.jpg 1579w\" sizes=\"(max-width: 768px) 100vw, 768px\" \/>\t\t\t\t\t\t\t\t\t\t\t<figcaption class=\"widget-image-caption wp-caption-text\">Fig. 3:  Left: The trapezoidal cross section of a single strip in the twelve sided lamination. Right: A closeup of two adjacent strips.<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-2a912c3 elementor-widget elementor-widget-heading\" data-id=\"2a912c3\" data-element_type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t<h5 class=\"elementor-heading-title elementor-size-default\">How do you make very thin bamboo strips?<\/h5>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-0ae3885 elementor-widget elementor-widget-text-editor\" data-id=\"0ae3885\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<p>How are we going to fabricate a twelve strip ya?\u00a0 How are we to produce the thin and narrow strips?\u00a0 A twelve strip layup secured by a chord wrapped in a helix is stabilized by the induced circumferential and radial forces much as in the hexagon case, but the stability is more delicate.\u00a0 The process to be described emerges by common sense trial and error:\u00a0 Just engage and &#8220;think with your hands.&#8221;<\/p><p>Though the strips can be processed from thin Yadake stalks,\u00a0 large diameter stalks such as yumishi use are a better choice.\u00a0 There are no leaf pockets, and the outer layer of the stalk with its high density of strong elastic fibers is close to 2 mm thick.\u00a0 The basic tools are a band saw, spindle sander, and some improvised jigs attached to the spindle sander.\u00a0\u00a0 Though these are large, ordinary tools, we nevertheless achieve\u00a0 the final tiny cross section of the strips in incremental steps.\u00a0<\/p><p>First, we band saw a large bamboo stalk into strips 2 cm wide and 130 cm long.\u00a0 Ya are rarely longer than 110 cm.\u00a0 The extra length allows for inevitable &#8220;boo-boos.&#8221;\u00a0\u00a0 Rough preliminary sanding flattens the raised nodal bumps on the outer surface of a strip.\u00a0 The inner surface is flattened by passing it through the spindle sander jig depicted schematically in the Fig. 4a.\u00a0\u00a0 For the rough preliminary sanding, we use the\u00a0 flat sanding belt with a coarse 60 grit.\u00a0 Placing the strip flat surface down on the band saw table, we cut the wide strips into finer strips roughly half a centimeter wide.\u00a0 These are passed through the spindle sander jig again.\u00a0 As before, the outer surface contacts the fence, and the inside surface is sanded to achieve a thickness just over a millimeter.\u00a0 Next, the outer surface is flattened by another pass as depicted in Fig. 4b.\u00a0 We remove as little as possible of the strong fibers close to the outer surface.\u00a0 More passes trim the widths of the strips down to 4 mm.\u00a0 At this stage, we have a large collection of strips with rectangular cross sections close to 4 mm by 1 mm.<\/p>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t<div class=\"elementor-element elementor-element-d748f42 e-flex e-con-boxed e-con e-parent\" data-id=\"d748f42\" data-element_type=\"container\" data-settings=\"{&quot;content_width&quot;:&quot;boxed&quot;}\" data-core-v316-plus=\"true\">\n\t\t\t\t\t<div class=\"e-con-inner\">\n\t\t\t\t<div class=\"elementor-element elementor-element-cc6cd7a elementor-widget elementor-widget-image\" data-id=\"cc6cd7a\" data-element_type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t<figure class=\"wp-caption\">\n\t\t\t\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"768\" height=\"373\" src=\"https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2024\/03\/sand_jig-768x373.jpg\" class=\"attachment-medium_large size-medium_large wp-image-1258\" alt=\"\" srcset=\"https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2024\/03\/sand_jig-768x373.jpg 768w, https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2024\/03\/sand_jig-300x146.jpg 300w, https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2024\/03\/sand_jig-1024x497.jpg 1024w, https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2024\/03\/sand_jig.jpg 1400w\" sizes=\"(max-width: 768px) 100vw, 768px\" \/>\t\t\t\t\t\t\t\t\t\t\t<figcaption class=\"widget-image-caption wp-caption-text\">Fig. 4:  Schematic of the jig for initial rough sanding.  (a). Inner surface.  (b) Outer surface.<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-c88f2e7 elementor-widget elementor-widget-text-editor\" data-id=\"c88f2e7\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<p>For the remaining fine work, we replace the sanding belt by a 3&#8243; drum with a fine 120 grit sleeve.\u00a0\u00a0 The motion of the drum is more precise than the belt. \u00a0 We sand the inside surface of the strips to trim their thickness down to the design value of 0.8 mm.\u00a0 To produce the final trapezoidal cross section of the strips, we employ the reconfigured jig depicted in Fig. 5.\u00a0 The schematic cross sectional views show how it operates, and the photograph shows how it looks.\u00a0 Admittedly, all this is crude.\u00a0 Indeed, there is intial trial and error to get the width of the strips right.\u00a0 Once set up, you should produce more strips than nominally needed for all the ya you want.\u00a0 For instance, six ya require 72 strips, but I&#8217;d be inclined to make more than 80.\u00a0\u00a0<\/p>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t<div class=\"elementor-element elementor-element-280812f e-flex e-con-boxed e-con e-parent\" data-id=\"280812f\" data-element_type=\"container\" data-settings=\"{&quot;content_width&quot;:&quot;boxed&quot;}\" data-core-v316-plus=\"true\">\n\t\t\t\t\t<div class=\"e-con-inner\">\n\t\t\t\t<div class=\"elementor-element elementor-element-61dee0e elementor-widget elementor-widget-image\" data-id=\"61dee0e\" data-element_type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t<figure class=\"wp-caption\">\n\t\t\t\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"600\" height=\"708\" src=\"https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2024\/09\/trap_sand1.jpg\" class=\"attachment-medium_large size-medium_large wp-image-2586\" alt=\"\" srcset=\"https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2024\/09\/trap_sand1.jpg 600w, https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2024\/09\/trap_sand1-254x300.jpg 254w\" sizes=\"(max-width: 600px) 100vw, 600px\" \/>\t\t\t\t\t\t\t\t\t\t\t<figcaption class=\"widget-image-caption wp-caption-text\">Fig. 5:  Cutting the angled sides of strips.    The top panels show schematically how the trapezoidal cross section of the strips is produced.  The bottom panel is the photograph of the jig as it really is.<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-872d3fe elementor-widget elementor-widget-heading\" data-id=\"872d3fe\" data-element_type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t<h5 class=\"elementor-heading-title elementor-size-default\">How to lay up the bamboo strips<\/h5>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t<div class=\"elementor-element elementor-element-dfce7b5 e-flex e-con-boxed e-con e-parent\" data-id=\"dfce7b5\" data-element_type=\"container\" data-settings=\"{&quot;content_width&quot;:&quot;boxed&quot;}\" data-core-v316-plus=\"true\">\n\t\t\t\t\t<div class=\"e-con-inner\">\n\t\t\t\t<div class=\"elementor-element elementor-element-4773c47 elementor-widget elementor-widget-text-editor\" data-id=\"4773c47\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<p>The layup of the twelve strip lamination begins by constructing a &#8220;raft&#8221; of the strips:\u00a0 It is convenient to lay up the strips around a dowel as shown in the top photograph of Fig. 6. Initially, they are lightly secured by low tack masking tape. The masking tape strips don&#8217;t hold up when epoxy is applied, so they are replaced by paper strips attached to the bamboo strips by yellow wood glue. The paper strips don&#8217;t close the cylindrical raft, so we can pry it open and spread low viscosity epoxy on the inner surface. The low viscosity reduces excess glue accumulations outside of the actual glue lines between strips. The &#8220;clamping&#8221; is achieved by wrapping a chord tightly around the outer surface of the cylinder.\u00a0 The dowel that served as a mandrel to form the raft is removed in increments as the winding of the chord proceeds.\u00a0 The initial layup with uncured glue lines is malleable like a wire due to slippage along the glue lines.\u00a0 After a rough preliminary straightening by hand, the layup is secured for curing to a straight L-beam as shown in the second photograph of Fig. 6.<\/p>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t<div class=\"elementor-element elementor-element-a6e1081 e-flex e-con-boxed e-con e-parent\" data-id=\"a6e1081\" data-element_type=\"container\" data-settings=\"{&quot;content_width&quot;:&quot;boxed&quot;}\" data-core-v316-plus=\"true\">\n\t\t\t\t\t<div class=\"e-con-inner\">\n\t\t\t\t<div class=\"elementor-element elementor-element-830cb4b elementor-widget elementor-widget-image\" data-id=\"830cb4b\" data-element_type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t<figure class=\"wp-caption\">\n\t\t\t\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"678\" height=\"260\" src=\"https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2024\/03\/layup.jpg\" class=\"attachment-large size-large wp-image-1286\" alt=\"\" srcset=\"https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2024\/03\/layup.jpg 678w, https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2024\/03\/layup-300x115.jpg 300w\" sizes=\"(max-width: 678px) 100vw, 678px\" \/>\t\t\t\t\t\t\t\t\t\t\t<figcaption class=\"widget-image-caption wp-caption-text\">Fig. 6:  Layup of the twelve strip lamination.  In the top photograph, the blue strips are the low tack masking tape.  The white strips, paper secured with glue.  The bottom photograph shows the layup wrapped by securing thread, and lightly clamped to a straight aluminum L-bracket.<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-dfef718 elementor-widget elementor-widget-text-editor\" data-id=\"dfef718\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<p>The final cylindrical surface of the ya is producing by improvised &#8220;planing.&#8221;\u00a0 The first photograph of Fig. 7 shows two of the &#8220;planes.&#8221;\u00a0 Each consists of a strip of coarse sanding belt secured to a semi cylindrical channel cut in a pine board with a router.\u00a0 The second photograph shows the ya sitting in a slot of a long pine board as the &#8220;plane&#8221; is passed over it.<\/p>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-32705c0 elementor-widget elementor-widget-image\" data-id=\"32705c0\" data-element_type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t<figure class=\"wp-caption\">\n\t\t\t\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"997\" src=\"https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2024\/03\/planing-1024x997.png\" class=\"attachment-large size-large wp-image-1289\" alt=\"\" srcset=\"https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2024\/03\/planing-1024x997.png 1024w, https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2024\/03\/planing-300x292.png 300w, https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2024\/03\/planing-768x748.png 768w, https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2024\/03\/planing-1536x1496.png 1536w, https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2024\/03\/planing.png 1616w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/>\t\t\t\t\t\t\t\t\t\t\t<figcaption class=\"widget-image-caption wp-caption-text\">Fig. 7:  \"Planing\" the ya surface into a cylinder.  The top photograph shows the \"planes.\"  There are about four of them with different diameters.  The bottom photograph shows how the planes are used.<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-823d552 elementor-widget elementor-widget-text-editor\" data-id=\"823d552\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<p>Figure 8 shows a remnant of the final hollow cylinder left over from cutting the ya to length<\/p>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-feb01b6 elementor-widget elementor-widget-image\" data-id=\"feb01b6\" data-element_type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t<figure class=\"wp-caption\">\n\t\t\t\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"191\" height=\"300\" src=\"https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2024\/03\/cylinder-191x300.png\" class=\"attachment-medium size-medium wp-image-1290\" alt=\"\" srcset=\"https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2024\/03\/cylinder-191x300.png 191w, https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2024\/03\/cylinder.png 578w\" sizes=\"(max-width: 191px) 100vw, 191px\" \/>\t\t\t\t\t\t\t\t\t\t\t<figcaption class=\"widget-image-caption wp-caption-text\">Fig. 8:  A section of the laminated cylinder.<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-20afbf2 elementor-widget elementor-widget-heading\" data-id=\"20afbf2\" data-element_type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t<h4 class=\"elementor-heading-title elementor-size-default\">Comparison between laminated ya and take-ya<\/h4>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t<div class=\"elementor-element elementor-element-589dcb6 e-flex e-con-boxed e-con e-parent\" data-id=\"589dcb6\" data-element_type=\"container\" data-settings=\"{&quot;content_width&quot;:&quot;boxed&quot;}\" data-core-v316-plus=\"true\">\n\t\t\t\t\t<div class=\"e-con-inner\">\n\t\t\t\t<div class=\"elementor-element elementor-element-e90a573 elementor-widget elementor-widget-text-editor\" data-id=\"e90a573\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<p>Figure 9 depicts the fletched end of a finished ya.\u00a0 Its specifications are:\u00a0 length 11 cm, diameter 9.1 mm, weight 32.1 g.\u00a0 The weight compares favorably with the 35 g weight of the Shinsa ya mentioned at the beginning of this article.\u00a0 Its stiffness is 7% greater.<\/p><p>As explained on the page <a href=\"https:\/\/artchery.org\/wordpress\/index.php\/ya-selection-in-kyudo\/\">&#8220;Ya Selection in Kyudo,&#8221;<\/a> kyudoka with the longest yazuka (depth of draw) shooting the strongest yumi might be better served by ya much stiffer than standard take-ya.\u00a0 The laminated bamboo ya described here have stiffnesses close to traditional take-ya.\u00a0\u00a0 The page <a href=\"https:\/\/artchery.org\/wordpress\/index.php\/ya-selection-in-kyudo\/\">&#8220;Ya Selection in Kyudo&#8221;<\/a> documents tests of a ya whose stiffness is greatly increased by wrapping bamboo strips around a carbon tube. The carbon tube has an outer diameter of 8 mm and wall thickness of 0.5 mm; the bamboo strips wrapped around it are 0.3 mm thick. Such a ya looks almost the same as the pure bamboo ya depicted in Fig. 9, but is twice as stiff.<\/p>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-c916a15 elementor-widget elementor-widget-image\" data-id=\"c916a15\" data-element_type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t<figure class=\"wp-caption\">\n\t\t\t\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"573\" height=\"111\" src=\"https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2024\/03\/CIMG1612.jpg\" class=\"attachment-large size-large wp-image-1287\" alt=\"\" srcset=\"https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2024\/03\/CIMG1612.jpg 573w, https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2024\/03\/CIMG1612-300x58.jpg 300w\" sizes=\"(max-width: 573px) 100vw, 573px\" \/>\t\t\t\t\t\t\t\t\t\t\t<figcaption class=\"widget-image-caption wp-caption-text\">Fig. 9: The fletched end of a laminated bamboo ya produced by the process described on this page.<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t<div class=\"elementor-element elementor-element-a694a1b e-flex e-con-boxed e-con e-parent\" data-id=\"a694a1b\" data-element_type=\"container\" data-settings=\"{&quot;content_width&quot;:&quot;boxed&quot;}\" data-core-v316-plus=\"true\">\n\t\t\t\t\t<div class=\"e-con-inner\">\n\t\t\t\t<div class=\"elementor-element elementor-element-534d5a2 elementor-widget elementor-widget-image\" data-id=\"534d5a2\" data-element_type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"547\" height=\"32\" src=\"https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2023\/12\/watakuri.jpg\" class=\"attachment-large size-large wp-image-80\" alt=\"\" srcset=\"https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2023\/12\/watakuri.jpg 547w, https:\/\/artchery.org\/wordpress\/wp-content\/uploads\/2023\/12\/watakuri-300x18.jpg 300w\" sizes=\"(max-width: 547px) 100vw, 547px\" \/>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t","protected":false},"excerpt":{"rendered":"<p>Traditional aesthetics and material science merge in the yamishi\u2019s art High end take-ya, made from single stalks of Yadake bamboo according to ancient traditions, are beautiful and compelling to many kyudoka. However, they tend to warp with changes in temperature and humidity, and their strong circumferential stresses may lead to lengthwise splits. In contrast, Ya &hellip;<\/p>\n<p class=\"read-more\"> <a class=\"\" href=\"https:\/\/artchery.org\/wordpress\/index.php\/material-science-in-yamishis-art\/\"> <span class=\"screen-reader-text\">Material Science in Yamishi&#8217;s Art<\/span> Read More &raquo;<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"site-sidebar-layout":"no-sidebar","site-content-layout":"","ast-site-content-layout":"full-width-container","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"disabled","ast-breadcrumbs-content":"","ast-featured-img":"disabled","footer-sml-layout":"","theme-transparent-header-meta":"default","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"set","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""}},"footnotes":""},"class_list":["post-505","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/artchery.org\/wordpress\/index.php\/wp-json\/wp\/v2\/pages\/505","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/artchery.org\/wordpress\/index.php\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/artchery.org\/wordpress\/index.php\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/artchery.org\/wordpress\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/artchery.org\/wordpress\/index.php\/wp-json\/wp\/v2\/comments?post=505"}],"version-history":[{"count":301,"href":"https:\/\/artchery.org\/wordpress\/index.php\/wp-json\/wp\/v2\/pages\/505\/revisions"}],"predecessor-version":[{"id":2656,"href":"https:\/\/artchery.org\/wordpress\/index.php\/wp-json\/wp\/v2\/pages\/505\/revisions\/2656"}],"wp:attachment":[{"href":"https:\/\/artchery.org\/wordpress\/index.php\/wp-json\/wp\/v2\/media?parent=505"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}