Rev Author Line No. Line
4438 kaklik 1 // Parametric Pulley with multiple belt profiles
2 // by droftarts January 2012
3  
4 // Based on pulleys by:
5 // http://www.thingiverse.com/thing:11256 by me!
6 // https://github.com/prusajr/PrusaMendel by Josef Prusa
7 // http://www.thingiverse.com/thing:3104 by GilesBathgate
8 // http://www.thingiverse.com/thing:2079 by nophead
9  
10 // dxf tooth data from http://oem.cadregister.com/asp/PPOW_Entry.asp?company=915217&elementID=07807803/METRIC/URETH/WV0025/F
11 // pulley diameter checked and modelled from data at http://www.sdp-si.com/D265/HTML/D265T016.html
12  
13 /**
14 * @name Pulley
15 * @category Printed
16 * @using 1 x m3 nut, normal or nyloc
17 * @using 1 x m3x10 set screw or 1 x m3x8 grub screw
18 */
19  
20  
21 // tuneable constants
22  
23 teeth = 13; // Number of teeth, standard Mendel T5 belt = 8, gives Outside Diameter of 11.88mm
24 profile = 3; // 1=MXL 2=40DP 3=XL 4=H 5=T2.5 6=T5 7=T10 8=AT5 9=HTD_3mm 10=HTD_5mm 11=HTD_8mm 12=GT2_2mm 13=GT2_3mm 14=GT2_5mm
25  
26 motor_shaft = 8; // NEMA17 motor shaft exact diameter = 5
27 m3_dia = 3.2; // 3mm hole diameter
28 m3_nut_hex = 1; // 1 for hex, 0 for square nut
29 m3_nut_flats = 5.7; // normal M3 hex nut exact width = 5.5
30 m3_nut_depth = 2.7; // normal M3 hex nut exact depth = 2.4, nyloc = 4
31  
32 retainer = 1; // Belt retainer above teeth, 0 = No, 1 = Yes
33 retainer_ht = 1.5; // height of retainer flange over pulley, standard = 1.5
34 idler = 1; // Belt retainer below teeth, 0 = No, 1 = Yes
35 idler_ht = 1.5; // height of idler flange over pulley, standard = 1.5
36  
4446 kaklik 37 pulley_t_ht = 12.6; // length of toothed part of pulley, standard = 12
4438 kaklik 38 pulley_b_ht = 8; // pulley base height, standard = 8. Set to same as idler_ht if you want an idler but no pulley.
4446 kaklik 39 pulley_b_dia = 25; // pulley base diameter, standard = 20
4438 kaklik 40 no_of_nuts = 4; // number of captive nuts required, standard = 1
41 nut_angle = 90; // angle between nuts, standard = 90
42 nut_shaft_distance = 1.2; // distance between inner face of nut and shaft, can be negative.
43  
44  
45 // ********************************
46 // ** Scaling tooth for good fit **
47 // ********************************
48 /* To improve fit of belt to pulley, set the following constant. Decrease or increase by 0.1mm at a time. We are modelling the *BELT* tooth here, not the tooth on the pulley. Increasing the number will *decrease* the pulley tooth size. Increasing the tooth width will also scale proportionately the tooth depth, to maintain the shape of the tooth, and increase how far into the pulley the tooth is indented. Can be negative */
49  
50 additional_tooth_width = 0.2; //mm
51  
52 // If you need more tooth depth than this provides, adjust the following constant. However, this will cause the shape of the tooth to change.
53  
54 additional_tooth_depth = 0; //mm
55  
56 // calculated constants
57  
58 nut_elevation = pulley_b_ht/2;
59 m3_nut_points = 2*((m3_nut_flats/2)/cos(30)); // This is needed for the nut trap
60  
61 // The following set the pulley diameter for a given number of teeth
62  
63 MXL_pulley_dia = tooth_spacing (2.032,0.254);
64 40DP_pulley_dia = tooth_spacing (2.07264,0.1778);
65 XL_pulley_dia = tooth_spacing (5.08,0.254);
66 H_pulley_dia = tooth_spacing (9.525,0.381);
67 T2_5_pulley_dia = tooth_spaceing_curvefit (0.7467,0.796,1.026);
68 T5_pulley_dia = tooth_spaceing_curvefit (0.6523,1.591,1.064);
69 T10_pulley_dia = tooth_spacing (10,0.93);
70 AT5_pulley_dia = tooth_spaceing_curvefit (0.6523,1.591,1.064);
71 HTD_3mm_pulley_dia = tooth_spacing (3,0.381);
72 HTD_5mm_pulley_dia = tooth_spacing (5,0.5715);
73 HTD_8mm_pulley_dia = tooth_spacing (8,0.6858);
74 GT2_2mm_pulley_dia = tooth_spacing (2,0.254);
75 GT2_3mm_pulley_dia = tooth_spacing (3,0.381);
76 GT2_5mm_pulley_dia = tooth_spacing (5,0.5715);
77  
78 // The following calls the pulley creation part, and passes the pulley diameter and tooth width to that module
79  
80 if ( profile == 1 ) { pulley ( "MXL" , MXL_pulley_dia , 0.508 , 1.321 ); }
81 if ( profile == 2 ) { pulley ( "40 D.P." , 40DP_pulley_dia , 0.457 , 1.226 ); }
82 if ( profile == 3 ) { pulley ( "XL" , XL_pulley_dia , 1.27, 3.051 ); }
83 if ( profile == 4 ) { pulley ( "H" , H_pulley_dia ,1.905 , 5.359 ); }
84 if ( profile == 5 ) { pulley ( "T2.5" , T2_5_pulley_dia , 0.7 , 1.678 ); }
85 if ( profile == 6 ) { pulley ( "T5" , T5_pulley_dia , 1.19 , 3.264 ); }
86 if ( profile == 7 ) { pulley ( "T10" , T10_pulley_dia , 2.5 , 6.13 ); }
87 if ( profile == 8 ) { pulley ( "AT5" , AT5_pulley_dia , 1.19 , 4.268 ); }
88 if ( profile == 9 ) { pulley ( "HTD 3mm" , HTD_3mm_pulley_dia , 1.289 , 2.27 ); }
89 if ( profile == 10 ) { pulley ( "HTD 5mm" , HTD_5mm_pulley_dia , 2.199 , 3.781 ); }
90 if ( profile == 11 ) { pulley ( "HTD 8mm" , HTD_8mm_pulley_dia , 3.607 , 6.603 ); }
91 if ( profile == 12 ) { pulley ( "GT2 2mm" , GT2_2mm_pulley_dia , 0.764 , 1.494 ); }
92 if ( profile == 13 ) { pulley ( "GT2 3mm" , GT2_3mm_pulley_dia , 1.169 , 2.31 ); }
93 if ( profile == 14 ) { pulley ( "GT2 5mm" , GT2_5mm_pulley_dia , 1.969 , 3.952 ); }
94  
95 // Functions
96  
97 function tooth_spaceing_curvefit (b,c,d)
98 = ((c * pow(teeth,d)) / (b + pow(teeth,d))) * teeth ;
99  
100 function tooth_spacing(tooth_pitch,pitch_line_offset)
101 = (2*((teeth*tooth_pitch)/(3.14159265*2)-pitch_line_offset)) ;
102  
103 // Main Module
104  
105 module pulley( belt_type , pulley_OD , tooth_depth , tooth_width )
106 {
107 echo (str("Belt type = ",belt_type,"; Number of teeth = ",teeth,"; Pulley Outside Diameter = ",pulley_OD,"mm "));
108 tooth_distance_from_centre = sqrt( pow(pulley_OD/2,2) - pow((tooth_width+additional_tooth_width)/2,2));
109 tooth_width_scale = (tooth_width + additional_tooth_width ) / tooth_width;
110 tooth_depth_scale = ((tooth_depth + additional_tooth_depth ) / tooth_depth) ;
111  
112  
113 // ************************************************************************
114 // *** uncomment the following line if pulley is wider than puller base ***
115 // ************************************************************************
116  
4446 kaklik 117 // translate ([0,0, pulley_b_ht + pulley_t_ht + retainer_ht ]) rotate ([0,180,0])
4438 kaklik 118  
119 difference()
120 {
121 union()
122 {
123 //base
124  
125 if ( pulley_b_ht < 2 ) { echo ("CAN'T DRAW PULLEY BASE, HEIGHT LESS THAN 2!!!"); } else {
126 rotate_extrude($fn=pulley_b_dia*2)
127 {
128 square([pulley_b_dia/2-1,pulley_b_ht]);
129 square([pulley_b_dia/2,pulley_b_ht-1]);
130 translate([pulley_b_dia/2-1,pulley_b_ht-1]) circle(1);
131 }
132 }
133  
134 difference()
135 {
136 //shaft - diameter is outside diameter of pulley
137  
138 translate([0,0,pulley_b_ht])
139 rotate ([0,0,360/(teeth*4)])
140 cylinder(r=pulley_OD/2,h=pulley_t_ht, $fn=teeth*4);
141  
142 //teeth - cut out of shaft
143  
144 for(i=[1:teeth])
145 rotate([0,0,i*(360/teeth)])
146 translate([0,-tooth_distance_from_centre,pulley_b_ht -1])
147 scale ([ tooth_width_scale , tooth_depth_scale , 1 ])
148 {
149 if ( profile == 1 ) { MXL();}
150 if ( profile == 2 ) { 40DP();}
151 if ( profile == 3 ) { XL();}
152 if ( profile == 4 ) { H();}
153 if ( profile == 5 ) { T2_5();}
154 if ( profile == 6 ) { T5();}
155 if ( profile == 7 ) { T10();}
156 if ( profile == 8 ) { AT5();}
157 if ( profile == 9 ) { HTD_3mm();}
158 if ( profile == 10 ) { HTD_5mm();}
159 if ( profile == 11 ) { HTD_8mm();}
160 if ( profile == 12 ) { GT2_2mm();}
161 if ( profile == 13 ) { GT2_3mm();}
162 if ( profile == 14 ) { GT2_5mm();}
163 }
164  
165 }
166  
167 //belt retainer / idler
168 if ( retainer > 0 ) {translate ([0,0, pulley_b_ht + pulley_t_ht ])
169 rotate_extrude($fn=teeth*4)
170 polygon([[0,0],[pulley_OD/2,0],[pulley_OD/2 + retainer_ht , retainer_ht],[0 , retainer_ht],[0,0]]);}
171  
172 if ( idler > 0 ) {translate ([0,0, pulley_b_ht - idler_ht ])
173 rotate_extrude($fn=teeth*4)
174 polygon([[0,0],[pulley_OD/2 + idler_ht,0],[pulley_OD/2 , idler_ht],[0 , idler_ht],[0,0]]);}
175  
176 }
177  
178 //hole for motor shaft
179 translate([0,0,-1])cylinder(r=motor_shaft/2,h=pulley_b_ht + pulley_t_ht + retainer_ht + 2,$fn=motor_shaft*4);
180  
181 //captive nut and grub screw holes
182  
183 if ( pulley_b_ht < m3_nut_flats ) { echo ("CAN'T DRAW CAPTIVE NUTS, HEIGHT LESS THAN NUT DIAMETER!!!"); } else {
184 if ( (pulley_b_dia - motor_shaft)/2 < m3_nut_depth + 3 ) { echo ("CAN'T DRAW CAPTIVE NUTS, DIAMETER TOO SMALL FOR NUT DEPTH!!!"); } else {
185  
186 for(j=[1:no_of_nuts]) rotate([0,0,j*nut_angle])
187 translate([0,0,nut_elevation])rotate([90,0,0])
188  
189 union()
190 {
191 //entrance
192 translate([0,-pulley_b_ht/4-0.5,motor_shaft/2+m3_nut_depth/2+nut_shaft_distance]) cube([m3_nut_flats,pulley_b_ht/2+1,m3_nut_depth],center=true);
193  
194 //nut
195 if ( m3_nut_hex > 0 )
196 {
197 // hex nut
198 translate([0,0.25,motor_shaft/2+m3_nut_depth/2+nut_shaft_distance]) rotate([0,0,30]) cylinder(r=m3_nut_points/2,h=m3_nut_depth,center=true,$fn=6);
199 } else {
200 // square nut
201 translate([0,0.25,motor_shaft/2+m3_nut_depth/2+nut_shaft_distance]) cube([m3_nut_flats,m3_nut_flats,m3_nut_depth],center=true);
202 }
203  
204 //grub screw hole
205 rotate([0,0,22.5])cylinder(r=m3_dia/2,h=pulley_b_dia/2+1,$fn=8);
206 }
207 }}
208 }
209  
210 }
211  
212  
213 // Tooth profile modules
214  
215 module MXL()
216 {
217 linear_extrude(height=pulley_t_ht+2) polygon([[-0.660421,-0.5],[-0.660421,0],[-0.621898,0.006033],[-0.587714,0.023037],[-0.560056,0.049424],[-0.541182,0.083609],[-0.417357,0.424392],[-0.398413,0.458752],[-0.370649,0.48514],[-0.336324,0.502074],[-0.297744,0.508035],[0.297744,0.508035],[0.336268,0.502074],[0.370452,0.48514],[0.39811,0.458752],[0.416983,0.424392],[0.540808,0.083609],[0.559752,0.049424],[0.587516,0.023037],[0.621841,0.006033],[0.660421,0],[0.660421,-0.5]]);
218 }
219  
220 module 40DP()
221 {
222 linear_extrude(height=pulley_t_ht+2) polygon([[-0.612775,-0.5],[-0.612775,0],[-0.574719,0.010187],[-0.546453,0.0381],[-0.355953,0.3683],[-0.327604,0.405408],[-0.291086,0.433388],[-0.248548,0.451049],[-0.202142,0.4572],[0.202494,0.4572],[0.248653,0.451049],[0.291042,0.433388],[0.327609,0.405408],[0.356306,0.3683],[0.546806,0.0381],[0.574499,0.010187],[0.612775,0],[0.612775,-0.5]]);
223 }
224  
225 module XL()
226 {
227 linear_extrude(height=pulley_t_ht+2) polygon([[-1.525411,-1],[-1.525411,0],[-1.41777,0.015495],[-1.320712,0.059664],[-1.239661,0.129034],[-1.180042,0.220133],[-0.793044,1.050219],[-0.733574,1.141021],[-0.652507,1.210425],[-0.555366,1.254759],[-0.447675,1.270353],[0.447675,1.270353],[0.555366,1.254759],[0.652507,1.210425],[0.733574,1.141021],[0.793044,1.050219],[1.180042,0.220133],[1.239711,0.129034],[1.320844,0.059664],[1.417919,0.015495],[1.525411,0],[1.525411,-1]]);
228 }
229  
230 module H()
231 {
232 linear_extrude(height=pulley_t_ht+2) polygon([[-2.6797,-1],[-2.6797,0],[-2.600907,0.006138],[-2.525342,0.024024],[-2.45412,0.052881],[-2.388351,0.091909],[-2.329145,0.140328],[-2.277614,0.197358],[-2.234875,0.262205],[-2.202032,0.334091],[-1.75224,1.57093],[-1.719538,1.642815],[-1.676883,1.707663],[-1.62542,1.764693],[-1.566256,1.813112],[-1.500512,1.85214],[-1.4293,1.880997],[-1.353742,1.898883],[-1.274949,1.905021],[1.275281,1.905021],[1.354056,1.898883],[1.429576,1.880997],[1.500731,1.85214],[1.566411,1.813112],[1.625508,1.764693],[1.676919,1.707663],[1.719531,1.642815],[1.752233,1.57093],[2.20273,0.334091],[2.235433,0.262205],[2.278045,0.197358],[2.329455,0.140328],[2.388553,0.091909],[2.454233,0.052881],[2.525384,0.024024],[2.600904,0.006138],[2.6797,0],[2.6797,-1]]);
233 }
234  
235 module T2_5()
236 {
237 linear_extrude(height=pulley_t_ht+2) polygon([[-0.839258,-0.5],[-0.839258,0],[-0.770246,0.021652],[-0.726369,0.079022],[-0.529167,0.620889],[-0.485025,0.67826],[-0.416278,0.699911],[0.416278,0.699911],[0.484849,0.67826],[0.528814,0.620889],[0.726369,0.079022],[0.770114,0.021652],[0.839258,0],[0.839258,-0.5]]);
238 }
239  
240 module T5()
241 {
242 linear_extrude(height=pulley_t_ht+2) polygon([[-1.632126,-0.5],[-1.632126,0],[-1.568549,0.004939],[-1.507539,0.019367],[-1.450023,0.042686],[-1.396912,0.074224],[-1.349125,0.113379],[-1.307581,0.159508],[-1.273186,0.211991],[-1.246868,0.270192],[-1.009802,0.920362],[-0.983414,0.978433],[-0.949018,1.030788],[-0.907524,1.076798],[-0.859829,1.115847],[-0.80682,1.147314],[-0.749402,1.170562],[-0.688471,1.184956],[-0.624921,1.189895],[0.624971,1.189895],[0.688622,1.184956],[0.749607,1.170562],[0.807043,1.147314],[0.860055,1.115847],[0.907754,1.076798],[0.949269,1.030788],[0.9837,0.978433],[1.010193,0.920362],[1.246907,0.270192],[1.273295,0.211991],[1.307726,0.159508],[1.349276,0.113379],[1.397039,0.074224],[1.450111,0.042686],[1.507589,0.019367],[1.568563,0.004939],[1.632126,0],[1.632126,-0.5]]);
243 }
244  
245 module T10()
246 {
247 linear_extrude(height=pulley_t_ht+2) polygon([[-3.06511,-1],[-3.06511,0],[-2.971998,0.007239],[-2.882718,0.028344],[-2.79859,0.062396],[-2.720931,0.108479],[-2.651061,0.165675],[-2.590298,0.233065],[-2.539962,0.309732],[-2.501371,0.394759],[-1.879071,2.105025],[-1.840363,2.190052],[-1.789939,2.266719],[-1.729114,2.334109],[-1.659202,2.391304],[-1.581518,2.437387],[-1.497376,2.47144],[-1.408092,2.492545],[-1.314979,2.499784],[1.314979,2.499784],[1.408091,2.492545],[1.497371,2.47144],[1.581499,2.437387],[1.659158,2.391304],[1.729028,2.334109],[1.789791,2.266719],[1.840127,2.190052],[1.878718,2.105025],[2.501018,0.394759],[2.539726,0.309732],[2.59015,0.233065],[2.650975,0.165675],[2.720887,0.108479],[2.798571,0.062396],[2.882713,0.028344],[2.971997,0.007239],[3.06511,0],[3.06511,-1]]);
248 }
249  
250 module AT5()
251 {
252 linear_extrude(height=pulley_t_ht+2) polygon([[-2.134129,-0.75],[-2.134129,0],[-2.058023,0.005488],[-1.984595,0.021547],[-1.914806,0.047569],[-1.849614,0.082947],[-1.789978,0.127073],[-1.736857,0.179338],[-1.691211,0.239136],[-1.653999,0.305859],[-1.349199,0.959203],[-1.286933,1.054635],[-1.201914,1.127346],[-1.099961,1.173664],[-0.986896,1.18992],[0.986543,1.18992],[1.099614,1.173664],[1.201605,1.127346],[1.286729,1.054635],[1.349199,0.959203],[1.653646,0.305859],[1.690859,0.239136],[1.73651,0.179338],[1.789644,0.127073],[1.849305,0.082947],[1.914539,0.047569],[1.984392,0.021547],[2.057906,0.005488],[2.134129,0],[2.134129,-0.75]]);
253 }
254  
255 module HTD_3mm()
256 {
257 linear_extrude(height=pulley_t_ht+2) polygon([[-1.135062,-0.5],[-1.135062,0],[-1.048323,0.015484],[-0.974284,0.058517],[-0.919162,0.123974],[-0.889176,0.206728],[-0.81721,0.579614],[-0.800806,0.653232],[-0.778384,0.72416],[-0.750244,0.792137],[-0.716685,0.856903],[-0.678005,0.918199],[-0.634505,0.975764],[-0.586483,1.029338],[-0.534238,1.078662],[-0.47807,1.123476],[-0.418278,1.16352],[-0.355162,1.198533],[-0.289019,1.228257],[-0.22015,1.25243],[-0.148854,1.270793],[-0.07543,1.283087],[-0.000176,1.28905],[0.075081,1.283145],[0.148515,1.270895],[0.219827,1.252561],[0.288716,1.228406],[0.354879,1.19869],[0.418018,1.163675],[0.477831,1.123623],[0.534017,1.078795],[0.586276,1.029452],[0.634307,0.975857],[0.677809,0.91827],[0.716481,0.856953],[0.750022,0.792167],[0.778133,0.724174],[0.800511,0.653236],[0.816857,0.579614],[0.888471,0.206728],[0.919014,0.123974],[0.974328,0.058517],[1.048362,0.015484],[1.135062,0],[1.135062,-0.5]]);
258 }
259  
260 module HTD_5mm()
261 {
262 linear_extrude(height=pulley_t_ht+2) polygon([[-1.89036,-0.75],[-1.89036,0],[-1.741168,0.02669],[-1.61387,0.100806],[-1.518984,0.21342],[-1.467026,0.3556],[-1.427162,0.960967],[-1.398568,1.089602],[-1.359437,1.213531],[-1.310296,1.332296],[-1.251672,1.445441],[-1.184092,1.552509],[-1.108081,1.653042],[-1.024167,1.746585],[-0.932877,1.832681],[-0.834736,1.910872],[-0.730271,1.980701],[-0.62001,2.041713],[-0.504478,2.09345],[-0.384202,2.135455],[-0.259708,2.167271],[-0.131524,2.188443],[-0.000176,2.198511],[0.131296,2.188504],[0.259588,2.167387],[0.384174,2.135616],[0.504527,2.093648],[0.620123,2.04194],[0.730433,1.980949],[0.834934,1.911132],[0.933097,1.832945],[1.024398,1.746846],[1.108311,1.653291],[1.184308,1.552736],[1.251865,1.445639],[1.310455,1.332457],[1.359552,1.213647],[1.39863,1.089664],[1.427162,0.960967],[1.467026,0.3556],[1.518984,0.21342],[1.61387,0.100806],[1.741168,0.02669],[1.89036,0],[1.89036,-0.75]]);
263 }
264  
265 module HTD_8mm()
266 {
267 linear_extrude(height=pulley_t_ht+2) polygon([[-3.301471,-1],[-3.301471,0],[-3.16611,0.012093],[-3.038062,0.047068],[-2.919646,0.10297],[-2.813182,0.177844],[-2.720989,0.269734],[-2.645387,0.376684],[-2.588694,0.496739],[-2.553229,0.627944],[-2.460801,1.470025],[-2.411413,1.691917],[-2.343887,1.905691],[-2.259126,2.110563],[-2.158035,2.30575],[-2.041518,2.490467],[-1.910478,2.66393],[-1.76582,2.825356],[-1.608446,2.973961],[-1.439261,3.10896],[-1.259169,3.22957],[-1.069074,3.335006],[-0.869878,3.424485],[-0.662487,3.497224],[-0.447804,3.552437],[-0.226732,3.589341],[-0.000176,3.607153],[0.226511,3.589461],[0.447712,3.552654],[0.66252,3.497516],[0.870027,3.424833],[1.069329,3.33539],[1.259517,3.229973],[1.439687,3.109367],[1.608931,2.974358],[1.766344,2.825731],[1.911018,2.664271],[2.042047,2.490765],[2.158526,2.305998],[2.259547,2.110755],[2.344204,1.905821],[2.411591,1.691983],[2.460801,1.470025],[2.553229,0.627944],[2.588592,0.496739],[2.645238,0.376684],[2.720834,0.269734],[2.81305,0.177844],[2.919553,0.10297],[3.038012,0.047068],[3.166095,0.012093],[3.301471,0],[3.301471,-1]]);
268 }
269  
270 module GT2_2mm()
271 {
272 linear_extrude(height=pulley_t_ht+2) polygon([[0.747183,-0.5],[0.747183,0],[0.647876,0.037218],[0.598311,0.130528],[0.578556,0.238423],[0.547158,0.343077],[0.504649,0.443762],[0.451556,0.53975],[0.358229,0.636924],[0.2484,0.707276],[0.127259,0.750044],[0,0.76447],[-0.127259,0.750044],[-0.2484,0.707276],[-0.358229,0.636924],[-0.451556,0.53975],[-0.504797,0.443762],[-0.547291,0.343077],[-0.578605,0.238423],[-0.598311,0.130528],[-0.648009,0.037218],[-0.747183,0],[-0.747183,-0.5]]);
273 }
274  
275 module GT2_3mm()
276 {
277 linear_extrude(height=pulley_t_ht+2) polygon([[-1.155171,-0.5],[-1.155171,0],[-1.065317,0.016448],[-0.989057,0.062001],[-0.93297,0.130969],[-0.90364,0.217664],[-0.863705,0.408181],[-0.800056,0.591388],[-0.713587,0.765004],[-0.60519,0.926747],[-0.469751,1.032548],[-0.320719,1.108119],[-0.162625,1.153462],[0,1.168577],[0.162625,1.153462],[0.320719,1.108119],[0.469751,1.032548],[0.60519,0.926747],[0.713587,0.765004],[0.800056,0.591388],[0.863705,0.408181],[0.90364,0.217664],[0.932921,0.130969],[0.988924,0.062001],[1.065168,0.016448],[1.155171,0],[1.155171,-0.5]]);
278 }
279  
280 module GT2_5mm()
281 {
282 linear_extrude(height=pulley_t_ht+2) polygon([[-1.975908,-0.75],[-1.975908,0],[-1.797959,0.03212],[-1.646634,0.121224],[-1.534534,0.256431],[-1.474258,0.426861],[-1.446911,0.570808],[-1.411774,0.712722],[-1.368964,0.852287],[-1.318597,0.989189],[-1.260788,1.123115],[-1.195654,1.25375],[-1.12331,1.380781],[-1.043869,1.503892],[-0.935264,1.612278],[-0.817959,1.706414],[-0.693181,1.786237],[-0.562151,1.851687],[-0.426095,1.9027],[-0.286235,1.939214],[-0.143795,1.961168],[0,1.9685],[0.143796,1.961168],[0.286235,1.939214],[0.426095,1.9027],[0.562151,1.851687],[0.693181,1.786237],[0.817959,1.706414],[0.935263,1.612278],[1.043869,1.503892],[1.123207,1.380781],[1.195509,1.25375],[1.26065,1.123115],[1.318507,0.989189],[1.368956,0.852287],[1.411872,0.712722],[1.447132,0.570808],[1.474611,0.426861],[1.534583,0.256431],[1.646678,0.121223],[1.798064,0.03212],[1.975908,0],[1.975908,-0.75]]);
283 }