Improving a cheap barbell
My home gym equipment is cheap and second-hand, but it works for me, except for a minor issue with the barbell. It is a cheap hex bolt barbell that I picked up at a garage sale, and although it's straight it wasn't stored properly and there was some rust in between the shaft and the sleeve at the very end. The red area in the diagram below shows where it would stick and keep from rotating properly. I tried disassembling it and cleaning it, which helped a bit but didn't fix the issue. So, with a flash of inspiration I searched and purchased a cheap pair of roller thrust bearings. They were 4 mm thick, with the right inner and outer diameter to fit around the problem area and separate the shaft and sleeve. They work perfectly, and now the sleeves and weights rotate smoothly.