Quote Originally Posted by routercnc View Post
My mk2 and mk3 used aluminium profile to bolt the rails to and I made plenty of good parts with it (including parts for the current mk4 under construction).

I did not flatten the surfaces or prep them and it made a very useable machine.

You can buy pre-machined aluminum profile which will make them very flat but you pay more for it.

Would aluminium box section be the same as profile for how flat they can be ? I believe they are both formed the same way.

Many thanks