// Z axis cover  rev 3
$fa = 1;
$fs = 0.4;

pleng       = 175;  // size of plate
pwide       = 125;
pthick      = 4;

chigh       = 24;   // internal 'headroom'
wall        = 3;    // wall thickness
iwall       = 6;    // inner wall thickness

threadX     = 118.61;       // correct by remeasurement
threadY     = 39.47;
dhole       = 43;
nhigh       = 33.6;         // height of chimney
nwall       = 6;            // chimney wall

difference(){
    union(){
        cylinder(d=dhole+2*nwall, h=nhigh);
        cylinder(d=dhole+nwall, h=nhigh+wall);
    }
    translate([0,0,-0.01])
        cylinder(h=nhigh+wall+0.02, d=dhole);
}