FFURG has a text-only tutorial on how to make 'fixed-blade' sabers into sabers with removable blade. I pretty much followed the entire procedure, but took some pictures to make things clearer. Here goes...
Take your 'fixed-blade' of choice:
Cut the blade off precisely at the emitter. Using a pick or a push pin, make holes in the blade and the hilt, in a manner that the holes are at the same position on both parts. Do this very carefully, by gently but firmly twisting the pick/pin in the parts. Only has to be 3 or 4 mm.:
Take a paperclip and superglue one end in the blade:
Cut off the paperclip so that the 'peg' in the blade is too long. Place the blade in the hole in the hilt and mark where the peg enters the hilt. This way you know how deep the hole in the hilt is and how long the peg has to be. I just held my thumbnail on the spot and eyeballed the length:
Place the blade in the hilt and check if it doesn't fall out easily. If so, drop a little superglue on the peg, put it in the hilt and very slowly turn the blade until the glue starts to settle. Familiar to tightening joints, not unknown to you, I'm sure:
That's all there is to it