Dirt King uniball cups are precision machined in house from 4130 chromoly steel. These cups have chamfered edges on the snap ring groove to eliminate scarring when pressing in the uniball. We hold +/- .0002 on the uniball cup bore allowing for a perfect press fit after welding when using our brass uniball slug. The slug helps absorb heat and keeps the cup from deforming throughout the welding process.