Quote Originally Posted by WoodKnot View Post
OK, I think a hugely embarrassing start, everything from the outset seems to be wrong.

Maybe I had made far too many assumptions and that is my fault!

I assumed that the ball screws would be slightly longer than the rails

I assumed that the ballscrew fittings would sit within the C Beam?

It all looks wrong! I don't think I am being a numpty but mine looks nothing like the others, even before I start.

Having parted with the best part of £800.00 just to get started, it's not a good start.

Will post some images in the next post as they are on my phone

WoodKnot
This is really bad news, I am sorry. I thought you bought 45x90 extrusions, which was discussed elsewhere as far as I can remember. The BF/BK12 fits nicely on those, using 6mm T-nuts, even though the most optimal would be 46mm center distance but the 45mm is fine. Anyway, I missed somewhere in the debate that you did in the end go for something else than 45x90. Hopefully you can use the ones you have now to something else and can buy 45x90 for your project. I normally buy my extrusions from Germany, a company named DOLD Mechatronic. They have good prices and good quality.

Too bad you wasted some money but I guess the lesson learned is to look at technical specs and drawings. While I never spend time on designing a machine in a fancy 3D modelling software, I do spend a lot of time on looking at drawings and specifications before I order something to avoid mistakes like this. Anyway, this is the reality of DIY world. We make mistakes and we learn and hopefully never repeat the same mistakes. Mistakes are made by the professionals also even in the industry, but their DIY is called prototype. The difference is that the prototype never gets sold, so we only see the nice final product, believing that it always looked like that.

Yes, normally the screws are longer than the rails, but with some smart design you can still have the same movement length as the rails allow, assuming the differences in length are not that large.

Regarding the alignment, I assumed you meant parallel alignment between rails and rails, and between rails and screws, plus squaring. As Jazz says, that's what you should spend time on, not aligning the rails with the extrusions. Of course, it helps if the extrusions are also aligned and squared to each other, but the main thing is that all the rails and screws run aligned and are squared to each other.