Method of grinding a substrate and method of manufacturing a glass substrate and a magnetic recording medium by the use of the glass substrate

Abstract

In a method of grinding side end surfaces of substrates, spacers are interposed between the substrates to form a stack of the substrates and the spacers. The spacers are slightly smaller in size than the substrates. The stack of the substrates and the spacers are ground by a rotatable brush or pad on the side end surfaces of the substrates so as to smooth chamfered portions of the substrates together with the side end surfaces.

1 - 18  (canceled).  
     
     
         19 . A glass substrate for magnetic recording medium, having a pair of main surfaces and inner and outer side end surfaces each of which is contiguous to the main surfaces and which have inner and outer side end surface portions, wherein the outer side end portion is ground together with the inner side end portion and has a surface roughness smaller than the inner side end portion.  
     
     
         20 . A glass substrate as claimed in  claim 19 , wherein each of the inner and the outer side end portions is contiguous to the main surfaces through a chamfered portion between the side end surface portion and each main surface.  
     
     
         21 . A glass substrate as claimed in  claim 20 , wherein each chamfered portion is also ground.  
     
     
         22 . A glass substrate as claimed in  claim 19 , wherein each of the inner and the outer side end portions has a surface roughness Rmax not greater than 1μm.  
     
     
         23 . A glass substrate as claimed in  claim 19 , wherein the glass substrate is subjected to side end surface grinding and is thereafter chemically reinforced.