this particular one is my design but the concept is common. If I was to do it again for a bigger diameter leadscrew (as I may be doing) I'd not use 8mm skate bearings but a 10mm x 30mm double row angular contact bearing type 3200-2RS as this has good radial and axial support and is simpler to use (one bearing instead of three), but obviously the screw root diameter needs to be >10mm.