No_Of_Pins = 8; Wall_T = 2; Wall_H = 7; Inner_W = 2.54 * No_Of_Pins; Inner_T = 2.54; difference() { cube([Inner_W + 2*Wall_T, Inner_T + 2*Wall_T, Wall_H], center=true); cube([Inner_W, Inner_T, 2*Wall_H], center=true); }