During one of my eBay explorations I bid on one of those batch auctions in order to get a couple of the included items. In addition to what I was looking for, I received a 135mm Ektanon Enlarging lens. My Beseler 67 enlarger only goes up to 6x7, but I thought that it might be useful to have the 135mm lens on a board, for those times like the postcard exchange when I wanted small prints from larger negatives.
The Ektanon lens was larger than the 39mm standard thread (about 42mm IIRC) so I had a machine shop cut the hole in a blank lensboard I had. Unfortunately, that was wasted money - the bellows on my Beseler enlarger doesn't extend far enough to focus the 135mm lens.
Oh well, it is the lessons you learn...