Summary

Singer sewing machines with a horizontal gripper need a two to one revolution gear. If the gripper gets stuck, the smaller wormgear is damaged easily while the larger one remains intact. Likely this is caused by inferior plastic used for the smaller gear. It is quite difficult to remove the axle such that the defect wormgear can be replaced, but it is not impossible. However, be prepared to spend a few hours !

Print Settings

Printer Brand:

TEVO

                                            <p class="detail-setting printer"><strong>Printer: </strong>                     <div><p>Tarantula</p></div></p>                                                                                <p class="detail-setting resolution"><strong>Resolution: </strong>                     <div><p>0.15 mm layer 0.4 mm nozzle</p></div></p>                                                                                <p class="detail-setting infill"><strong>Infill: </strong>                     <div><p>100%</p></div></p>                                                    <strong>Filament:</strong> Sum PETG                Gold

Post-Printing

no post printing required

            <div><p>thats all</p></div>

How I Designed This

Open scad file

            <div><p>The worm gear has teeth both outside and inside, because the iron carrier has small teeth in order to prevent slipping of the wormgear. There are 17 teeth on the inside. The openscad file is shown below. </p><p>$fn=120;</p><p>module camwheel(min,delta,hoogte)<br>/<em> this function generates a closed contour with 4 points with varying distance from the center (parameter delta). Th function floor(a/2)%2 generates a series 0,0,1,1,0,0,1,1,0,0,1,1,0,0,1,1,0,0,1,1..</em>/<br>{<br>{linear_extrude(hoogte,twist=-76.8)<br>polygon(<br>[ for (a = [1 : 1 : 48]) [ (min-delta<em>(floor(a/2)%2)) </em> sin(a<em>7.5), (min-delta</em>(floor(a/2)% 2)) <em> cos(a</em>7.5) ] ]);<br>}<br>}<br>module camwheel2(min,delta,hoogte)<br>/<em> module to give the inside small theeth<br>17 teeth, same angle as outside  </em>/<br>{<br>{linear_extrude(hoogte,twist=-76.8)<br>polygon(<br>[ for (a = [1 : 1 : 68]) [ (min-delta<em>(floor(a/2)%2)) </em> sin(a<em>5.2941176), (min-delta</em>(floor(a/2)% 2)) <em> cos(a</em>5.2941176) ] ]);<br>}<br>}<br>difference(){<br>union(){<br>translate([0,0,2.5])<br>camwheel(6.725,1.6,19.0);</p><pre><code>   cylinder(r=7.24,h=2.5);}   translate([0,0,-0.01])   cylinder(r=4.7,h=2.51);    translate([0,0,2.49])  camwheel2(4.40,0.42,19.02);}</code></pre></div>                <p class="detail-image"><img src="https://cdn.thingiverse.com/assets/84/17/00/94/90/6aa06686-dab5-4fce-9f96-153e3f2382e5.png"></p>

wormgear singer sewing machine