Anet A8 threaded rod bracket with slots for M4 or #10 pan/round head screws

thingiverse

Same hold-down/alignment clamp as https://www.thingiverse.com/thing:2390954 but this one has slots for M4 or #10 round-head screws instead of countersunk holes for flat-head screws. Why slots? After mounting your printer to a surface, you should check your Y-axis to X-axis alignment by printing a large square and seeing that all four corners have right angles. I did this and noticed that two of the corners were about 89 degrees and the other two were about 91 degrees, i realized that I needed to push the front of my printer about 3mm to the left, in order to make the Y-axis perfectly perpendicular to the X-axis.