[katran]

Hi Katran

Looks nice, as long as you can get that belt tight, and the bearings don't rattle. However, there are two details you should consider.

The first is that the surfaces of the Al extrusion are never perfectly flat. There is always some warpage coming out of the extrusion die. That means you should probably skim top and bottom surfaces very lightly before building. But there is a problem here too: see next.

The second is related to the first. When the outer surface of the extrusion is not perfectly flat, you do get some bending in the whole thing when you clamp it down onto something using nuts in the channels. This can make skimming the surfaces tricky if the whole thing is slightly warped at the start by clamping it down.

So ... you may need to skim top and bottom surfaces twice each, very lightly, before building. Pity - that removes the anodising, and the anodising can be rough on the cutters.
That said, if you are maching wood rather than steel, both problems may be minor.

Cheers

That's corect , the Al extrusion is not perfectly flat ... I will do the exact thing that you described ( skimming the surfaces ) .
Good call , thanks for the tip .

As I said , this project is for study ... precision is not critical , but I would like to go as far as I can ( maybe 0.025mm , if I'm lucky ... )

Thanks

[wizard]

That's corect , the Al extrusion is not perfectly flat ... I will do the exact thing that you described ( skimming the surfaces ) .
Good call , thanks for the tip .

As I said , this project is for study ... precision is not critical , but I would like to go as far as I can ( maybe 0.025mm , if I'm lucky ... )

Thanks

I'm not sure an extrusion is the right choice at all here. If you want to put alignment keys or pins into the sub plate you have limited options with an extrusion compared to a solid piece of aluminum. That is for alignment to the mills table but the same thing goes for the head stock and tail stock. Ideally you would be able to drop everything in place on the mill and have it line up with little adjust, if any, needed.

Obviously you don't want the tail stock pinned in place but you still need a key to keep it in alignment with the headstock.