I don't know where to post this so move it as appropriate, or just pick out the websites and add them above, whatever.
One topic that comes up over and over is using enlarger lenses for macro. Brilliant idea, but it takes various adapters, rings, caps, elbow grease and duct tape to do it. It can be fun to do, but it's also reinventing the wheel. There are off the shelf solutions.
A German company makes adapters for enlarger lenses (which tend to have non-standard threads, like 40.5x0.5mm on Nikkors). He makes them with 3 camera mount threads, either M39, M42, or T2, which lets you mount on just about any camera with an added camera specific adapter. It's the enlarger lens front thread that is tough to find, and here they are:
Reverse adapters for enlarging lenses
On the The MFlenses forum there is a high quality kit of adapters, rings and tubes developed for using all sorts of enlarger lenses on M43 and Sony mirrorless cameras, as well as Sony SLRs. So here it is:
The VNEX enlarger lens project V2.0