I have three Tsubaki 50mm diameter grade C5 ballscrews, double-nut zero backlash type, that are about 42-43" in length. Each end is machined, one end has a large internal hex and external metric locking screw threads, the other end has a section turned for the pulley (pulley end is floating end, I guess?)
Still wrapped in plastic, new old stock replacements for Okuma machines.
Reply via PM for more information and photos. I will have to re-measure lead as I can't find my notes. Bought them to rebuild an older lathe but ended up selling the lathe still configured for manual ops.
275$ each plus shipping to you. Each screw is an easy 40lbs. Perfect for that larger CNC mill build, or retrofit-two are 42" and one 43" length.