Method of electrolytically coating and etching bearing surfaces

Claim 1

A PROCESS OF TREATING A MACHINE PART TO PROVIDE AN ELECTROLYTICALLY-DEPOSITED BEARING SURFACE THEREON, WHICH COMPRISES ELECTROLYTICALLY DEPOSITING A METALLIC LAYER ON SUCH A PART TO A DEPTH TO PROVIDE A BEARING SURFACE OF SUBSTANTIALLY A DESIRED FINAL BEARING SIZE, COVERING THE ELECTROLYTICALLY-DEPOSITED BEARING SURFACE BY A MASK HAVING PERFORATIONS DISTRIBUTED OVER ITS AREA AND WHICH IS RESISTANT TO ATTACK BY AN ELECTROLYTIC ETCHING SOLUTION, IMMERSING IN A BATH OF AN ELECTROLYTIC ETCHING SOLUTION THE PART HAVING THE METALLIC LAYER ELECTROLYTICALLY DEPOSITED THEREON AND THE PERFORATED MASK COVERING SUCH LAYER, AND PASSING AN ELECTRIC CURRENT FROM AN EXTERNAL SOURCE THROUGH THE BATH OF ELECTROLYTIC ETCHING SOLUTION IN SUCH DIRECTION THAT SAID PART CONSTITUTES THE ANODE UNTIL THE PORTIONS OF THE ELECTROLYTICALLY-DEPOSITED METALLIC LAYER EXPOSED THROUGH THE PERFORATIONS IN THE MASK TO THE ETCHING SOLUTION ARE ETCHED TO A DEPTH SUFFICIENT TO FORM SHALLOW LUBRICANT RETAINING RECESSES WHILE THE PORTIONS OF SAID LAYER COVERED BY THE PORTIONS OF THE MASK INTERVENING THE PERFORATIONS THEREIN ARE NOT EXPOSED TO THE ETCHING SOLUTION AND REMAIN UNETCHED AND SMOOTH.