In my case, I should set the length of the rectangle to be 100*(100/98.5) = 101.5mm (see second image). This means that I should ask the printer to print larger objects if I want them to be of real size. First, note that the rectangle's new size should be:įor example, I printed my first version and measured the rectangle's width as 98.5mm instead of the requested 100mm. What you want to do is print the scale again, but this time ask the printer to print it so that the final print is in the correct scale (I'll show you how to do that in a second). It's probably going to be slightly different than 100mm, so you'll need to correct for that to get the Vernier scale just right. To make sure that your Vernier scale printed correctly first print the page as is. The other is a long rectangle who's width is 100mm (see first image). There are two objects in the file, one is the Vernier scale, and it should measure 39mm long. Their dimensions were set so that if you print the template on an A4 printer paper (landscape), they print out to real size. But ordinary printers are not designed to be so accurately calibrated, so how we do that that?Īttached is a PowerPoint file with 2 objects. To do that, we need to make sure that our Vernier scale is accurate! That is - it's dimensions are exactly what we want them to be. We're going to print out a Vernier scale. This brings our measurements to a resolution of 0.1mm with uncertainty of ~1/40mm (it's actually lower). In my case, I used a Vernier scale which has 10 ticks with a diatance of 3.9mm between each one, instead of 4. Usually, mechanical calipers reach 0.1mm, which is what we'll reach here. The fact that the Vernier scale makes a fraction of the main scale means that only one of the ticks on the Vernier scale will align with the ticks on the main scale for each distance, allowing you to reach resolutions better than 1mm. I won't go into detail about how Vernier interpolation works, but the working principal is that we align a 2nd ruler next to the main one, who's scale is a tiny bit different than the original scale (for example, ticks on the Vernier scale could be 0.9mm apart, instead of 1mm). To reach resolution of higher than 1mm (the scale on ordinary rulers), we need to add a way to read in between two ticks. Super cheap print (~30grams of PLA) + super cheap ruler = high accuracy. STL's, Tinkercad & more - all included here. Right-hand / left-handed versions available. Turn a ruler (1mm resolution) into a caliper (with 0.1mm resolution). It's also possible to make a caliper without attaching an actual ruler, but I figure an actual ruler would be more robust & reliable (see the step about attaching a ruler to the caliper for details). Let me just add that making a reliable caliper was my #1 priority, so while making the tool I'll also show you how to overcome the accuracy limitations posed by your 3D & regular printers too, which will allow you to achieve good results. If you're new to 3D printing, this is a great first project for you! The prints are fairly simple and you'll end up having a caliper, which is often used when you want to design your own models. I used my 3D printer to make it, but if people are interested I might make one out of stuff everyone can find. In this instructable I'll show you how to turn a ruler into a caliper. Plus, I figured that if I made a CAD model I could make a left-handed version too! You guys are always forgotten, but not anymore! Also, by using adding a Vernier scale I could reach a resolution of 0.1mm. I figured that if I base my caliper on a ruler, which is super cheap and 100% reliable, I could end up with a very reliable caliper. For those of you who are unfamiliar with what a caliper is, it's a tool that is most often used to measure out/inner diameters of objects, and there are more than a few instructables on how to use them. After I was done mourning over my 20$, I decided to make my own. Spent 20$ on it, and it's completely worthless - totally unreliable. I recently ordered a digital caliper from China.
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