Process of Manufacturing Power Tool Component

Abstract

A method of making a wear and fatigue resistant component of a power tool (e.g., a clutch) includes providing a quantity of base steel and a quantity of alloying elements to be added to the base steel to form a desired alloyed grade of steel. The base steel and alloying elements are combined and melted to produce a molten alloyed steel (e.g., SAE 9310 or AISI M2). The molten alloyed steel is cast using a near-net-shape investment casting process to form a component of a power tool. An edge of the component is pre-radiused. and the component is case hardened after the edge of the component has been pre-radiused. In one implementation, the component is a clutch that has a lifespan of at least twice a lifespan of a second clutch that has not been pre-radiused prior to case hardening.

1 . A method of making a wear and fatigue resistant component of a power tool comprising:
 providing a quantity of base steel;   providing a quantity of alloying elements to be added to the base steel to form a desired alloyed grade of steel, wherein the alloying elements include at least approximately 1% nickel by weight and at least approximately 0.4% chromium by weight;   combining and melting the quantity of base steel and the quantity of alloying elements to produce a molten alloyed steel;   casting the molten alloyed steel using a near-net-shape investment casting process to form a component of a power tool; and   pre-radiusing an edge of the component; and   case hardening the component after pre-radiusing the edge of the component.   
   
   
       2 . The method of  claim 1 , wherein the alloying elements comprise at least approximately 2% nickel by weight and at least approximately 0.8% chromium by weight. 
   
   
       3 . The method of  claim 2 , wherein the alloying elements comprise at least approximately 3% nickel by weight and at least approximately 1% chromium by weight. 
   
   
       4 . The method of  claim 3 , wherein the alloying elements comprise at most approximately 3.5% nickel by weight and at most approximately 1.4% chromium by weight. 
   
   
       5 . The method of  claim 1 , wherein the molten alloyed steel comprises SAE 9310 steel. 
   
   
       6 . The method of  claim 1 , further comprising subjecting the component to a cryogenic treatment after case hardening. 
   
   
       7 . The method of  claim 1 , wherein the casting step comprises forming the component as a clutch with a helical spline. 
   
   
       8 . The method of  claim 1 , wherein the casting step comprises forming the component as a clutch with a lug, and the pre-radiusing step comprises pre-radiusing an edge of the lug. 
   
   
       9 . The method of  claim 1 , wherein the casting step comprises forming the component as a clutch for a screw gun, wherein the clutch has a lifespan of at least twice a lifespan of a second clutch that has been investment cast from the same molten alloyed steel and case hardened without pre-radiusing an edge of the second clutch. 
   
   
       10 . A method of making a wear and fatigue resistant component of a power tool comprising:
 providing a quantity of base steel;   providing a quantity of alloying elements to be added to the base steel to form a desired alloyed grade of steel, wherein the alloying elements include molybdenum and tungsten having a total amount by weight of at least approximately 5%;   combining and melting the quantity of base steel and the quantity of alloying elements to produce a molten alloyed steel;   casting the molten alloyed steel using a near-net-shape investment casting process to form a component of a power tool; and   pre-radiusing an edge of the component; and   case hardening the component after pre-radiusing the edge of the component.   
   
   
       11 . The method of  claim 10 , wherein the alloying elements comprise molybdenum and tungsten having a total amount by weight of at least approximately 7%. 
   
   
       12 . The method of  claim 1 , wherein the alloying elements comprise molybdenum and tungsten having a total amount by weight of at least approximately 9%. 
   
   
       13 . The method of  claim 12 , wherein the alloying elements comprise molybdenum and tungsten having a total amount by weight of approximately 11%. 
   
   
       14 . The method of  claim 13 , wherein the alloying elements further comprise at least approximately 0.5% vanadium by weight and at least approximately 3% chromium by weight. 
   
   
       15 . The method of  claim 10 , wherein the molten alloyed steel comprises AISI M2 steel. 
   
   
       16 . The method of  claim 10 , further comprising subjecting the component to a cryogenic treatment after case hardening. 
   
   
       17 . The method of  claim 10 , wherein the casting step comprises casting the component as a clutch with at least one helical spline. 
   
   
       18 . The method of  claim 10 , wherein the casting step comprises casting the component as a clutch with at least one lug, and the pre-radiusing step comprises pre-radiusing an edge of the at least one lug. 
   
   
       19 . The method of  claim 10 , wherein the casting step comprises forming the component as a clutch for a screw gun, wherein the clutch has a lifespan that is greater than a lifespan of a second clutch that has been investment cast from the same molten alloyed steel without case hardening and pre-radiusing. 
   
   
       20 . A method of making a highly wear and fatigue resistant clutch for a screw gun, comprising:
 providing a quantity of base steel;   providing a quantity of alloying elements to be added to the base steel to form a desired alloyed grade of steel;   combining and melting the quantity of base steel and the quantity of alloying elements to produce a molten alloyed steel;   casting the molten alloyed steel using a near-net-shape investment casting process to form a clutch for a screw gun; and   pre-radiusing an edge of the clutch; and   case hardening the clutch after pre-radiusing the edge of the clutch,   wherein the clutch has a lifespan of at least twice a lifespan of a second clutch that has not been pre-radiused prior to case hardening.