The build up of swarf, specifically cutting wood, is what worried me a bit with bearings. I had a wood cutting bandsaw with full bearing guides and the two on either side of the blade on the lower guide would occasionally have their circumferences caked with wood dust, this would place one heck of a radial load on both and control the position of the blade with less accuracy. The upper guide bearings were largely immune to this as the blade had a couple turns prior to fling everything off. The metal blocks on my wood cutting 14" Deltahave a shearing action presented to anything stuck to the side of the blade so the blade stays pretty clean. My 20" BS has disc style lower side guides and bearings for the upper side guides, tha hybrid approach works very well. I have a couple porta-band saws and they both use bearing guides but at a lower sfm than I suspect this old Rockwell spins at in low gear.