<p>Marlin has a <a href="http://marlinfw.org/tools/lin_advance/k-factor.html" rel="nofollow noreferrer">Linear Advance calibration pattern generator</a>, but I find it's hard to use because:</p>

<ul>
<li>It only prints the initial layer on the bed, where bed irregularities interfere with accurate reading of it.</li>
<li>It doesn't do proper retraction and priming, so a mess of strings and underextruded initial segments/non-adhesion mess up the results.</li>
<li>It's hard to visually evaluate.</li>
<li>Getting a very wide range of K values involves multiple runs.</li>
<li>It's hard to clean up.</li>
</ul>

<p>Is there a better procedure for calibration of K value for linear advance?</p>

[{'answer_id': 11876, 'author': '0scar', 'author_id': 5740, 'author_profile': 'https://3dprinting.stackexchange.com/users/5740', 'pm_score': 1, 'selected': False, 'text': '<p>I don\'t know what the value is, but there are a few ways to find out. It is very hard to measure this with a caliper, but it can be done, mark the upper and bottom of e.g. 10 windings and measure this with a caliper. Alternatively measure how much the screw drops after 10 full turns. </p>\n\n<p>There are special tools that give you the answer directly, they cost a few Euros/bucks but can be very handy; a thread gauge, just place the 0.5&nbsp;mm and the 0.7&nbsp;mm beside the screw and you will instantly see which is the correct one.</p>\n\n<p><a href="https://i.stack.imgur.com/UYqFm.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/UYqFm.jpg" alt="enter image description here"></a></p>\n\n<p><em>I bought mine at a typical Chinese vendor site.</em></p>\n'}, {'answer_id': 11877, 'author': 'fred_dot_u', 'author_id': 854, 'author_profile': 'https://3dprinting.stackexchange.com/users/854', 'pm_score': 2, 'selected': False, 'text': "<p>Possibly tongue in cheek here, but if you can detect a 0.2 mm change, you may be able to determine visually the thread pitch, although it means de-tuning your bed for the experiment. Keeping close count is part of the experiment and you can reverse the count easily enough.</p>\n\n<p>Make contact with the nozzle at the location of one screw. Count the turns in order to set the screw back to original location (or don't worry, re-tune later).</p>\n\n<p>If the pitch is 0.5 mm, two complete turns would give you a millimeter, while the 0.7 mm pitch will give you 1.4 mm. Make it four turns and the difference is more apparent. That would present a 2.0 mm compared to 2.8 mm for the two types of threads.</p>\n"}, {'answer_id': 11886, 'author': 'Andrew Morton', 'author_id': 11255, 'author_profile': 'https://3dprinting.stackexchange.com/users/11255', 'pm_score': 4, 'selected': True, 'text': "<p>I measured mine with a thread gauge and it says the pitch is <strong>0.7 mm</strong>.</p>\n<p>So, as the stock adjustment wheels have 14 bumps around their circumference, turning by one of those is an adjustment of exactly 0.05 mm (assuming no backlash).</p>\n<p>I can't speak for anyone else's, but due to the availability of replacement height adjustment wheels which don't specify alternative thread pitches, I <em>guess</em> that's the only one in use. I encourage you to verify my finding before relying on it.</p>\n"}, {'answer_id': 11887, 'author': 'Trish', 'author_id': 8884, 'author_profile': 'https://3dprinting.stackexchange.com/users/8884', 'pm_score': 2, 'selected': False, 'text': '<p>Just as Andrew, I did run a quick test to measure it: on my corner closest to &lt;0,0,0>, a little stud is poking out. <em>Just</em> enough to screw on a threadcutter I know without any cutting happening:</p>\n\n<p><a href="https://i.stack.imgur.com/W4fWc.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/W4fWc.jpg" alt="enter image description here"></a>\n<a href="https://i.stack.imgur.com/7jWyf.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/7jWyf.jpg" alt="enter image description here"></a></p>\n\n<p>Indeed, it is <strong>M4x0.7</strong>, aka coarse thread.</p>\n'}]
['https://3dprinting.stackexchange.com/questions/11893', 'https://3dprinting.stackexchange.com', 'https://3dprinting.stackexchange.com/users/11157/']