The SMALLEST Protractor for CAD modelling (0.1 degree precision angle measurement tool)

prusaprinters

<p>Classic protractors use verniers (nonius scales) with 2, 5 or 10 minutes marks (0.033, 0.083 and 0.167 degrees correspondingly as one minute is 1/60 of a degree). Modern CAD software deal with decimal values of a degree so I made this protractor with 6 minutes marks, and that is exactly 0.1 degree. You will enjoy this precision ONLY if your printer is able to to print this model with high accuracy.</p><p>This model is for CAD modelling (to measure and duplicate things with a 3D printer). I also have a <a href="https://www.printables.com/model/172288-professional-protractor-for-cad-modelling-0025-deg">professional CAD protractor</a> and a model of <a href="https://www.printables.com/model/159562-the-smallest-protractor-for-drawing-transparent">the smallest protractor for drawing</a>.</p><p>Weight: ~ 15g.<br>Size: ~ 11x6 cm.<br>Print time: ~2h.<br>100% printable (no additional parts needed).</p><p><strong>Preparing.</strong></p><p>Before printing, make sure that your printer is in good condition: the X/Y belts should not be loose and the extrusion should be properly configured. You should also learn how to deal with "elephant foot", rough corners, curling and other common problems as they will surely make a useless toy from this precise tool. You should also learn how to change filament on a certain height to be able to print the scales with a different color.</p><p>The model is optimized for 0.2 mm layer. All the tolerances were optimized for PETG. I also tried PLA but I gave up with it when I found that the scale can be easily scratched off with a nail. At the same time you will have to use a knife to get rid of the scale when it is printed with PETG, so it is better for this model! I think if you find a silver-color PETG, your tool will look really professional as if it were made from real steel.</p><p>There are 4 parts: Base (main scale), Arm (vernier scale), Central nut and Fixing nut. They should be printed separately as the filament color change is made on different heights. The nuts can be printed together at some distance to allow more time for better cooling of layers. If you have problems with the quality of the thread, you can "refresh" it using standard metal M5 bolts and nuts with 0.8 mm thread but I made such high tolerances that they should screw easily with hand right after printing.</p><p>Do not rotate the nuts - print them as they are oriented in the STL to avoid support. Yeah, one of them is printed upside-down - this is the way it should be.</p><p><strong>Print settings.</strong></p><p>Print settings for CURA - “Z-seam position” is used to determine where the layer will be started. I found the best positions to save measuring surfaces from seams. The starting position for the labels is used to prevent the nozzle from starting to print the thin scale right after filament change, when under/over-extrusion problems often take place. So first we print some useless decorative stuff like the smiley to clean the nozzle and only then we print the scale. Z-seam position:</p><p>Base: &nbsp; back-right; labels: front.<br>Arm: back-left<strong>*</strong>; labels: back-left.</p><p><i><strong>* - Required, otherwise it will start to print level 23 overhanging parts in the air and spoil the whole thing.</strong></i></p><p>Other settings as you with. I used 3 walls, 3 top, 3 bottom, 50% grid infill, monotonic top/bottom order (transparent PETG looks disattracting without it). If you are a tough guy, I recommend 100% infill for the arm because I managed to break one that was made with 50% infill).</p><p><strong>Assembling the tool.</strong></p><p>Put the main scale under the vernier scale, align 2 studs with 2 holes and push on the main scale. The scale should lay on the arm without any gap or clearance. Screw the central nut till the end, use M8 wrench if needed (supplied with Ender3) but remember that it's a plastic stud and it can be broken if a lot of force is applied. The central nut will not block the scale when it is completely screwed up. Now screw the fixing nut till the end using your fingers and unscrew it ~45-90 degrees back to allow easy rotation of the arm. You can screw up the fixing nut completely any time later when you need to fix the value, for example when it is not possible to read it at once because of low light conditions or inconvenient position of the protractor during measurement.</p><p><strong>Ready to use!</strong></p><p>Before using this tool, make sure that the scales marks were printed correctly. To make it short I will call the main scale M and the vernier scale V, so check that when:<br>M=0/180, V1=M9/M-9;<br>M=45/135, V1=M36/144;<br>M=90, V1=M99.</p><p>If you don't understand what I mean, here is the picture showing the correct position of the scales for 0, 45 and 90 degrees:</p><figure class="image"><img src="https://media.printables.com/media/prints/164482/rich_content/6e0854ed-3a46-4805-929f-acb9bfec4783/vernier-test.jpg#%7B%22uuid%22%3A%22c80c9a6f-bd76-4125-ad78-0076e2d5aaaa%22%2C%22w%22%3A1803%2C%22h%22%3A1080%7D"></figure><p>If this is not correct, your printer evidently has some problems with precise positioning of the nozzle and you need to fix it somehow. If it is correct, now put the protractor to a flat surface, it should show exactly 0 degrees. If it doesn't the thing most likely has excess of plastic somewhere due to low quality of the print. Examine the measuring surfaces and make sure they are completely flat (there is no "elephant foot", bold corners and other defects). Use a sharp knife to remove redundant plastic if needed and test it again. If it shows 0 degrees on a flat surface, congratulations, you made a really working tool for precise measurements - enjoy it! If you still can't make it work correctly, I can only recommend you to fix or change your printer! I printed this tool on Ender3V2 and tested it a few days with different angles and it really works correctly when printed properly!</p><p><strong>How to measure.</strong></p><p>Use the inside part of the arm and the right part of the vernier to measure 0-90 degrees angles.&nbsp; Use the outside part of the arm and the left part of the vernier to measure 90-180 degrees angles. The following photos show examples of 30 and 120 degrees measurements.</p><figure class="image"><img src="https://media.printables.com/media/prints/164482/rich_content/fa4f0ead-d043-42ae-a08f-749fcad64efa/p1080698_tn.jpg#%7B%22uuid%22%3A%22de749755-20ed-4ed3-970e-94f841b8fe66%22%2C%22w%22%3A1920%2C%22h%22%3A1080%7D"></figure><p><img src="https://media.printables.com/media/prints/164482/rich_content/dc53e074-6eab-42e4-8221-1042551fb578/p1080696_tn.jpg#%7B%22uuid%22%3A%225da50e44-f758-42e1-bcb1-15e273a02556%22%2C%22w%22%3A1920%2C%22h%22%3A1080%7D">If you don't know how to measure angles using a vernier scale, search "how to use a vernier scale" and learn it. Remember that this protractor has 0.1 degree (6 minutes) vernier scale marks to simplify entering values in CAD software!</p><p><strong>Solution for PrusaSlicer (and maybe some other slicers) to slice the scale correctly.</strong></p><p>The marks in this protractor have only 0.42mm width and PrusaSlicer thinks that this tiny part of the model is unimportant and should not be printed. This model was designed for 0.4 mm line width that is default for 0.2 mm nozzle, so the marks have only 0.42 mm line width to be sliced properly, But PrusaSlicer has default setting of 0.45 mm width!!! I found 2 solutions:</p><p>1) Check "Detect thin walls" in the print settings, it will slice all the scale marks but also make "4" look strange :)</p><p>2) Go to Print Settings/Advanced/Extrusion width and change everything there from 0.45 to 0.4. It will make acceptable slicing but still it is worse than the one Cura makes.</p><p>I recommend using <a href="https://ultimaker.com/software/ultimaker-cura">Cura</a> to slice this print (there are Linux, Apple and Windows versions and they are free). It slices everything well with default settings. It also has a setting called "slicing tolerance" that can include even smaller things to be sliced! Middle (default) and Inclusive slice the scale well while Exclusive will slice it without the scale the way PrusaSlicer does. Besides, it has several useful settings to noticeably improve the quality of this print that PrusaSlicer doesn't, for example, it will not start to print the vernier scale plate from the air if you select the settings that I recommended. But PrusaSlicer does start it from the air and this may eventually make the rotation of the scale more difficult than it was designed.&nbsp;</p><figure class="image"><img src="https://media.printables.com/media/prints/164482/rich_content/3c3abc5e-4a57-4f1d-8e23-c1953b9dedec/prusaslicer.jpg#%7B%22uuid%22%3A%22d74c1059-4b86-41bb-8e11-3ffee7b8f188%22%2C%22w%22%3A1556%2C%22h%22%3A667%7D"></figure><p>&nbsp;</p><p><strong>PS: photos of your makes are welcome!</strong></p><p>&nbsp;</p>