Silentblock SC8UU

When I started with my Geetech Prusa Al, the noise, a mix of humming, hissing, rattling ... almost drove me mad. I had noticed the smooth rods excessive play in the bearings. Worse, they are regular "soft" stainless steel diam 7.92mm ! May be they produce it in that size to sell them as metrinch ? (standard metric 8mm and archaic 5/16 " ). Big savings anyway and it seems to be quite common. I replaced them with suitable hardened rods miked at 7.95 mm.
Now, to reduce further any play and compe