//120mm fan adaptor HEPA filter $fn=100; //You can adjust these four variables //Primarily the filter hole diameter screwhole=5; //fan screw hole diameter (5) filterhole=92; //HEPA filter hole diameter thickness=1.5; //Thickness of plastic layer (1.5) insert=10; //Length of insert into filter (10) //Do not adjust anything below here cone=(120-filterhole)/1.5; wall=thickness*2; difference(){ union(){ //flange translate([0,0,0]) cube([120,120,thickness]); //taper to filter insert translate([60,60,0]) cylinder(h=cone,d1=120,d2=filterhole); //filter insert translate([60,60,cone]) cylinder(h=insert,d=filterhole); } //taper to filter insert translate([60,60,0]) cylinder(h=cone,d1=116,d2=filterhole-wall); //filter insert translate([60,60,cone]) cylinder(h=insert,d=filterhole-wall); //fan attachment holes translate([7.5,7.5,-1]) cylinder(h=thickness+2,d=screwhole); translate([7.5,112.5,-1]) cylinder(h=thickness+2,d=screwhole); translate([112.5,7.5,-1]) cylinder(h=thickness+2,d=screwhole); translate([112.5,112.5,-1]) cylinder(h=thickness+2,d=screwhole); }