I have no idea where to put this, really, but here goes:

I have had the idea (on and off) to recement the rear element of an old brass Rodenstock (it's an Aplanat). It has balsam separation on the edge, and I am thinking of it as a project lens, as the element is very easy to take out. I guess sending it off to a specialist like John at Focal Point would be nice, but the value of the lens (apart from its sentimental value to me) is low. Doing it myself, I understand the risk of getting dust in there, and it not being centered, etc, so... maybe should I just leave as it is?

Where can I get some Vblocks (I guess they are called that?) or prisms to do the centering?