Multi-piece machine tool base

Abstract

A power tool having a base assembly with a first portion, which defines an upper surface, and a second portion that defines a lower surface. The first and second portions may be castings and are coupled to one another without machining the upper surface of the first portion or the lower surface of the second portion. After assembly of the base portion, the upper surface of the second portion is machined to define a flat reference surface. Construction of the power tool in this manner provides a robust base assembly that is relatively inexpensive to manufacture. A related method is also provided.

1 . A method comprising: 
 forming a base structure with a body portion that defines a support surface;    forming a plate structure;    coupling the plate structure to the base structure; and    machining the plate structure to define a flat reference surface only after the plate structure and the base structure have been coupled to one another;    wherein the support surface is not machined prior to the coupling of the plate structure and the base structure.    
   
   
       2 . The method of  claim 1 , wherein coupling the plate structure to the base structure comprises: 
 inserting a threaded fastener through the body portion; and    threadably engaging the threaded fastener to the plate structure.    
   
   
       3 . The method of  claim 2 , wherein the plate structure includes a boss that extends away from the flat reference surface.  
   
   
       4 . The method of  claim 3 , wherein the boss is received into a mounting aperture formed in the body portion.  
   
   
       5 . The method of  claim 1 , wherein coupling the plate structure to the base structure comprises: 
 forming a hole in the plate structure;    forming a hole in the body portion that is arranged generally transverse to the support surface; and    inserting a threaded fastener through the hole in the plate structure and the hole in the body portion.    
   
   
       6 . The method of  claim 5 , wherein the hole in the plate structure and the threaded fastener cooperate to locate the plate structure relative to the body.  
   
   
       7 . The method of  claim 6 , wherein the hole in the plate structure includes a countersunk portion and wherein the threaded fastener includes a conical portion that matingly engages the countersunk portion.  
   
   
       8 . The method of  claim 1 , further comprising forming a plurality of guide post mounting apertures into the base structure.  
   
   
       9 . The method of  claim 8 , wherein the guide post mounting apertures are formed into the base structure after the plate structure is coupled to the base structure.  
   
   
       10 . The method of  claim 1 , wherein the power tool is a planer.  
   
   
       11 . The method of  claim 1 , wherein the base structure is formed of a first material and the plate structure is formed of a second material that is different than the first material.  
   
   
       12 . The method of  claim 11 , wherein the first material is aluminum or magnesium and the second material is iron.  
   
   
       13 . The method of  claim 1 , wherein the base portion of the base structure includes a plurality of webs that cooperate to defines a plurality of void spaces, the void spaces being disposed beneath the plate structure when the base structure and the plate structure are coupled to one another.  
   
   
       14 . A power tool comprising a base assembly having a base structure and a plate structure, the base structure being formed of a first material and having a body portion that defines a support surface, the plate structure being formed of a second material, the plate structure being coupled to the base structure in abutment with the support surface, wherein the support surface is not machined prior to the coupling of the plate structure and the base structure and wherein the base assembly is machined to generate a flat reference surface only after the plate structure and the base structure have been coupled to one another.  
   
   
       15 . The power tool of  claim 14 , wherein a plurality of guide post mounting apertures are formed in the base assembly and wherein the power tool further comprises a plurality of guide posts disposed in the guide post mounting apertures.  
   
   
       16 . The power tool of  claim 15 , wherein the guide posts are fixedly coupled to the base assembly.  
   
   
       17 . The power tool of  claim 14 , further comprising a carriage movably coupled to the base assembly and a rotating cutter coupled to the carriage.  
   
   
       18 . A method comprising: 
 forming a base assembly with a first portion and a second portion, the first portion being formed of cast aluminum or magnesium and defining a bottom surface and an upper surface, the second portion being formed of cast iron and including a cast lower surface and a cast upper surface, the cast lower surface being abutted against the upper surface of the first portion;    fixturing the base assembly to a machine tool;    machining the second portion to define a reference surface that is generally parallel with a plane on which the lower surface of the first portion rests.    
   
   
       19 . The method of  claim 18 , further comprising: 
 forming a plurality of guide post mounting apertures into the base assembly; and    unfixturing the base assembly from the machine tool only after the guide post mounting apertures have been formed and the second portion has been machined to define the reference surface.    
   
   
       20 . The method of  claim 18 , wherein forming the base assembly includes clamping the first and second portions to one another with a plurality of threaded fasteners.