Now for the Y-axis linear rail assembly. The Y-axis must run above the X-axis linear block and a 3D part called a mounting plate is used to join both axes. First, we can mount the two NEMA 17 stepper motors. One is mounted on the top side of the plate and the other on the bottom side with M3 bolts. Then, two M5 bolts and nuts are fixed to the plate to install the GT2 pulleys in place. The two idler pulleys here are used to provide engagement for the X-axis GT2 belt and stepper motor pulley. It is recommended that the stepper motor gear pulley and the idler pulleys be almost flush. I used several nuts to align the idler pulleys.

Next, I placed the Y-axis linear rail on the plate and fixed it with two M5 bolts. The linear rail hole spacing in the X-axis applies to the Y-axis linear rail, if the hole widths and spacing are not compatible, you can create compatible holes with the help of a drill. After mounting the Y-axis linear rail, the two axes are connected to each other by fixing the mounting plate to the X-axis linear block using four M4 bolts.

Now that the machine has almost taken its main shape, we will add a pulley to the other side of the Y-axis linear rail, that is, to its idle end. This pulley will allow the belt for the Y axis to be installed in a cycle. You can choose this pulley as a toothed or idler pulley, I used a toothed pulley. For the assembly of the cycle pulley, I mounted the 3D part called 'Y-axis Pulley' to the linear rail with an M3 bolt. I also designed a support part due to the length of the Y-axis linear rail and the weight of the pen lifter part. In this way, I solved the wobble problem for this axis. I also designed a wheel with a bearing for smooth movement of the support part. I fixed the wheel with bearing to the support part with M5 bolt, and fixed the support part to the pulley part with M3 bolt. Now the Y axis linear block can reach any position in the workspace.