So looking at 12mm lead screws and below, it seems like a common method for fixing them in place is to use pillow blocks. The pillow block has set screws which clamp onto the lead screw, and you're all set. However, the common size pillow blocks are 8, 10 ,12, 15, 17, 20mm, etc. So for 12mm and below, it's easy to find a pillow block for them.
for 14mm and larger, I can't seem to find pillow blocks in that size. Is there another common practice that's used for these larger sizes? I could imagine a bushing could be insert into the pillow blocks of a larger size... but then I haven't been able to find bushings that would fit there either.
I'm sure there is an easy solution to this... I just haven't run across it yet. Thanks for any feedback!