I haven't checked them lately but I think mine are like 9 or 10mm diameter, but yeah, thread 'em and make custom length bolts, motor arbor extensions, just about anything a rod is used for, also being precision, they work well in bronze bearings for small linear actuation needs. The outer casings tend to, again, be made of high- quality steel, I just can't bring myself to turn them over to my recycle guy, I hoard them. ;-)