PS: there are kinda new material widly used for to build the CNC rails. It looks like this in the pirture: https://www.laudorts.lv/wp-content/uploads/2022/01/Profilu-katalogs2022-pdf-212x300.jpg

Nothing new about ally extruded profiles, though what is 'newer' is the range of shapes and sizes now available. But not all profile are equal; some of the stuff coming out of China lacks stiffness compared to Western extrusions. On the left is a 4545 profile from one of the top suppliers on AliExpress, and on the right, one from a UK supplier. There's a lot more 'meat' on the centre section and on the external flanges. The result is that the RH profile is 20% stiffer than the LH one...

 

Check out Misumi, they sell quality extrusions and components, pretty much all over the world.

 

Check out Misumi, they sell quality extrusions and components, pretty much all over the world.

Interestingly that Aliexpress wants 84GBP inc shipping for 2 x 700mm, whereas KJN in the UK charges 45GBP inc shipping for the same in a BOSCH Rexroth compatible extrusion which is stiffer than either of those above. Misumi UK site is down for maintenance at the mo, will check them out later.

Misumi charge 62Euro inc shipping (53GBP) from DE to UK. So cheapest to buy in UK from KJN for my next build. YMMV.