2 Pcs 2040 CNC 3D Printer Parts European Standard Anodized Linear Rail Aluminum Profile Extrusion for DIY 3D Printer Black (500mm)

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.

did what i needed

I don't like giving 1 star, but this is setting my project back and is going to make me look bad to my boss.Looking at the extrusion and even checking with a caliber, everything seems good, but no sled I have for either 20/20 or 20/40 will fit these extrusions. I have gone so far as to adjust the Eccentric nuts fully open, and the sled still will not slide on. I can't see the issue, but there is one.

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 center hole diameter was larger than the stock hole diameter on my 3d printers so I had to tap them 1mm larger and switch bolt sizes.They were perfect as a substitute for 2 missing pieces to a used Ender 5 Plus 3d printer. after reworking, drilling attachment holes and making a spacer to increase the length to match the 2 existing pieces.