They didnt seem to be openable from outside as they didnt come when I was pulling them out, so I open them from inside... now I cant put them back together so they are correctly aligned.
I might try again but I think I will have to buy a new set
Ok ! thank you for the reply! I didn't want to use too much force and break anything so I prayed the internals ! but now I cant put back the needles at the right place there are tiny sprockets with a kind of tiny spring. Seems almost impossible. Maybe you should add that the needles can be pulled from the front after removing the glass on your guide