19 showing the seal region 35 which receives o ring seal 33 by darkened lines present heat treatments of the general bearing portion of the rock bit are carried out by carburizing and then boronizing the bearing pin thus the prior art technique calls for carburizing and thereafter boronizing both the seal region 35 and the remaining area of the pin 47 this area 47 will sometimes be referred to as the 34 primary friction bearing region of the pin 34 the present invention is the discovery that wear on the general bearing of a rock bit head section can be prevented by applying a surface hardening treatment such as a carburizing treatment to the seal region 35 of the bearing pin while simultaneously boronizing only the remaining area 47 of the pin 19 while carburizing is the preferred surface treatment technique shown in the example which follows it should be understood that any surface treatment can be utilized which can be accomplished by the use of a solid packing mixture which can be packed around the bearing pin the preferred technique in addition to providing surface hardness provides improved chemical properties to the metal surface such as resistance to oxidation and chloride pitting thus the surface hardening technique utilized can be selected from the group consisting of carburizing siliconizing nitriding aluminizing or calorizing and other 34 pack 34 surface hardening techniques combinations of these treatments can also be used advantageously where the surface treatment selected for the seal region is carburization the preferred technique is pack carburizing.