Hi Henrick,

re:
> Would it be possible to create this object without those lines or can I dissolve those lines and
> keep the same solid form.

Yes if you were to model the object over again from scratch you would be able to avoid the little slivery surface by controlling the segmentation of your curves before you constructed surfaces from them.

"dissolving the lines" on the existing model is fairly difficult - it is possible to do something like that by working with individual surfaces and untrimming and retrimming them. There is an object repair tutorial here which goes over how to do this but it's fairly involved:
http://moi3d.com/forum/index.php?webtag=MOI&msg=446.17

Also here's a shorter one focused just on how to untrim:
http://moi3d.com/forum/index.php?webtag=MOI&msg=444.4

If you extract some surfaces and untrim them it looks like the 2 pieces originally come from the same cylinder so it's possible to recover that cylinder and retrim it.

But did you look at ralf's file above, he just tuned it up by deleting the little slivery surface area and once you've chamfered that you could build some new surfaces crossing the gap, that would probably take less time.

- Michael