Untitled

$fn = 50;

sampleLength = 2.8;
sampleWidth = 2.8;
sampleHeight = 0.5;

XYcorrf = 0.025;
Zcorrf = 0.05;

h = 0.0001;
r = 3;

x1 = 20-r*2;
y1 = 20-r*2;
z1 = 1.5-h;

x2 = sampleLength+XYcorrf;
y2 = sampleWidth+XYcorrf;
z2 = sampleHeight+Zcorrf;

r1 = 0.5;

id = "#256";

difference(){
    
    minkowski(){
            cube([x1,y1,z1], center = true);
            cylinder(h, r, center=true);
        }
    translate([0,0,z2])
    cube([x2, y2, z2], center = true);

    translate([-0.4,y1/2.3, z1/2-0.5+h])
    linear_extrude(0.5)
    text(id,2.5,halign = "center", valign = "center");
    
    translate([x2/2,0,z2])
    cylinder(z2,r1,r1, center = true);
        
    translate([-x2/2,0,z2])
    cylinder(z2,r1,r1, center = true);
        
    translate([0,y2/2,z2])
    cylinder(z2,r1,r1, center = true);
        
    translate([0,-y2/2,z2])
    cylinder(z2,r1,r1, center = true);