                 
//Bolt heught
#declare BH = .75;                        
//Bolt radius
#declare BR = 1;
                        
#declare BoltHead =

intersection{

  difference{

    cylinder{<0,0,0><0,BH,0> BR}
  
    union{
    
      #declare bn = 0;
      #while (bn < 360)
    
        box{<0, -BH, -2*BR> <2*BR, 2*BH, 2*BR> translate  BR*0.89*x rotate bn*y}
        #declare bn = bn + 60;
      #end 
    }
  
  }    
  union{          
    sphere{<0,0,0>BR scale <1,.4,1> translate 0.725*BH*y}
    cylinder{<0,0,0><0,.725*BH,0> BR+2}  
  }
}  
 
#declare BoltHeadWash =
union{
  object{BoltHead translate<0,.3.0>}
  cylinder{<0,0,0><0,.2,0>BR  +.2}
}