I'm assembling my LEAD 1515 and ran into a discrepancy in the build video. When assembling the two plate/wheel assemblies for the X-axis Carriage Assembly the video is very specific about putting the transmission components on the side where the nuts go on the 65mm screws. However, in the step of mounting the two assemblies to the V-slot it shows the transmission blocks on the other side, where the screw heads are. Which is correct? Edit: so after watching the rest of that step the end assembly shows the transmission blocks on the side with the nuts. Looks like the video was shot with an incorrectly assembled piece and then corrected at the end but not at the beginning.
Checkout the 3D model on the LEAD 1515's build page > files and drawings tab. In 3D you can zoom and investigate up close any sections you are unsure of. Its meant to have it open alongside the video OpenBuilds LEAD CNC Machine 1515 (60" x 60")