2 Pcs 2040 CNC 3D Printer Parts European Standard Anodized Linear Rail Aluminum Profile Extrusion for DIY 3D Printer Black (600mm)

Arrived as described

Dimensionally accurate, internal geometry as expected, and the surface anodizing robust. All of that for a nice price. Worked very well as additional structure for a heavily modified 3d printer with dual direct drive extrusion, dual x-axis linear roll bearings, twin z stepper lead screws, twin y-axis linear roll bearings, and a full outfit of 32 bit skr 1.4 turbo goodness. There are plans for a third Bowden extruder, but I need to figure out the control side of things before that happens...

I ordered the 500mm. They were received in a timely manner, the product was as pictured and advertised, the finish was uniform and undamaged and the rails were to length, straight and surface square. All things that I would expect from the product as advertised.The seller would likely sell more of these if they would list the dimensions beyond just the length.

Used for extending my cnc wood router. will add hiwin linear rails on top of two, but will eventually use solid aluminum for bottom rails but this will work for now

did what i needed

These are decent extrusions. I was drawn in by the price but for my application there was a workable flaw, the oversized end holes. If you do not plan to use hardware in the hole of these extrusions you will be happy.As many others have stated, the holes in the end are too big for to thread for m5 hardware which is the standard. The holes are somewhere around 5.2mm, which is the size of the drill bit that comes in a cheap m5 helicoil set, tap the hole for the helicoil, thread it in, and now you have perfectly usable m5 threads.

the 20mm is not the same as the 20x20 extrusion, and is too heavy for the use I was going to use it for.What I was really looking for was a carbon fiber version for weight reduction but apparently it is not yet being made.

Overall the extrusions are straight and exactly the same length. The plastic wrapping though is holding a lot of shavings which will spill out everywhere once opened. Prepare to open it over a trash can or somewhere easy to clean up.