to consider a machine ready to start work, I would make sure, especially with the Onefinity CNC machine, that it is
- rectangular (“squared”) and that it is
- coplanar (not twisted).
For checking the rectangularity, there were different methods suggested, but as a first check for rectangularity (“squaring”), I would take a bar gauge:
and stick its ends diagonally on the machine right where the chrome tubes go into the black aluminum block, first as a diagonal between left front and right rear, then right front to left rear. Since in a rectangle the two diagonals are identical, these two distances should be the same so the machine is square. If you can move the bar gauge to a greater length in one of the two positions than in the other, then the machine is not a rectangle but a parallelogram, that is, the angles are not right angles. This can lead not only to workpieces where right angles are not right, but also, in extreme cases, to blocking of the Y-sliders.
To adjust this, you need to loosen a little bit the screws of at least two adjacent machine feet (say, e.g. the left and the right front feet), as well as loosen the screws that attach the X-axis to the Y-sliders a bit, so that you can move the feet so that the machine becomes right-angled, i.e. both diagonals can be measured as equal with the bar gauge.
For a more accurate test for squareness, you should do a test with the machine milling a test rectangle. Create a rectangle as large as the workarea as g-code and run it on the machine using a v-bit (with minimal cutting depth), and then use a bar gauge or a ruler to check whether or not the diagonals are equal. If you take a ruler, its accuracy or its scale does not matter at all, just make a mark on it when you check one diagonal of the milled rectangle, and check if the mark is identical when you check the other diagonal of the rectangle with it.
The so-to-speak “official” thread in this forum about rectangularity of the machine is “Is your router frame a parallelogram? Mine was! ”
For the second check, the check for coplanarity (that the machine is not twisted), you can use the […]