Temporary change to first layer tab ahead of new video.

calibration.html

@@ -142,19 +142,20 @@
         <p>If this distance is too far, the filament will not be squished into the bed enough, potentially even printing in mid air, and the print will detach from the bed and fail.</p>
         <p>If the nozzle is too close, there will not be enough room for the extruded filament to take the correct shape, and it will be forced to squeeze outwards. In minor cases, the extruded line will be wider than necessary and produce <i>elephant's foot</i>. Prints like this may be quite hard to remove from the bed.</p>
         <p>In extreme cases, there will be no way for the filament to exit the nozzle, at best causing extruder stepper motor skipping, and even potentially even jamming the extruder/hot end.</p>
-        <p>A short animation of these concepts are shown in the following snippet:</p>
+        <p>The contents of this page are shown in detail in the following video:</p>
+        <img src="img/thumb.jpg" style="max-height:360px; margin-bottom:20px;" />
+        <!--
         <iframe width="480" height="360" src="https://www.youtube.com/embed/T-Z3GmM20JM?start=909&end=962" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
+        -->
         <h2>Manual Levelling Procedure</h2>
         <p>There are many techniques available, but a common one is to move the nozzle to the various corners of the bed, turning the levelling knobs until a standard piece of office paper can just fit between the bed and nozzle. A 0.1mm feeler gauge can be used, but make sure it doesn't have any oil on it that will contaminate the bed surface. Typically, this procedure is done with the bed at printing temperature (essential), and the nozzle close to printing temperature - just cool enough to prevent filament oozing out (optional).</p>
         <p>It is common to follow up with a first layer calibration print, and 'live level' the bed by continuing to adjust the knobs when the print is under way.</p>
-        <p>This process is depicted in detail in the following snippet, and a gcode generator is provided at the bottom of the page to generate a suitable test print:</p>
-        <iframe width="480" height="360" src="https://www.youtube.com/embed/T-Z3GmM20JM?start=961&end=1206" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
+        <p>This process is depicted in detail in the video above, and a gcode generator is provided at the bottom of the page to generate a suitable test print:</p>
         <h2>Auto Bed Levelling and Z offset</h2>
         <p>Auto bed levelling automates the procedure to some extent. A sensor such as a BLtouch, EZABL, strain gauge or peizo transducer is used to probe the bed in a grid formation. At each location, it measures the vertical height, building up an array of stored values, called a <i>mesh</i>. Manual mesh bed levelling can also be used to probe such a grid, but is still a manual process and hence not considered 'automatic'. Here is a visual representation of a probed mesh, shown with the <a href="https://plugins.octoprint.org/plugins/bedlevelvisualizer/" target="_blank">Bed level visualizer Octprint plugin</a>:</p>
         <a href="#" data-featherlight="img/ablmesh.jpg"><img class="thumb" src="img/ablmesh.jpg" /></a>
         <p>During printing, the firmware will reference the mesh and compensate for an angled and/or warped bed by raising and lowering the nozzle using Z axis movement. This means the nozzle can travel up and down to match the contours of the bed, ensuring a good first layer.</p>
-        <p>In the printer's bed is perfectly flat, it is reasonable to claim ABL is not needed. Some users may still prefer it for the added convenience. In the event that the bed is warped (very common), it can be impossible to get a good first layer without ABL or manual mesh bed levelling. An example of this situation is shown in the following snippet:</p>
-        <iframe width="480" height="360" src="https://www.youtube.com/embed/T-Z3GmM20JM?start=1206&end=1254" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
+        <p>In the printer's bed is perfectly flat, it is reasonable to claim ABL is not needed. Some users may still prefer it for the added convenience. In the event that the bed is warped (very common), it can be impossible to get a good first layer without ABL or manual mesh bed levelling. An example of this situation is shown in the video above.</p>
         <p>The bed can be probed at the start of the print with a <b>G29</b> command, with the resulting mesh immediately used to compensate as the initial layers are produced. Alternatively, the bed can also be probed some other time (while not printing), the mesh stored in the EEPROM and then restored with <b>M420 S1</b> at the start of a print. In this case the print will start sooner, since we do not need to wait for a new mesh to be probed, although it may not be as accurate if anything has changed since probing. Either of these gcode commands should come after the <b>G28</b> home command in the start gcode.</p>
         <p>Although ABL can compensate for a crooked/non-levelled bed, it is still better to attempt to level manually first and get everything in the  ballpark.</p>
         <p>Probing the bed and building a mesh only accounts for an uneven or warped bed. Like manual levelling, we still need to set the distance between the nozzle and bed to get a good first layer. This is where the Z offset comes in, which is simply the vertical distance between where the probe triggers vs the nozzle tip. Here are some examples:</p>