1// Start config
 2
 3// Standoffs
 4length = 6.5; //mm
 5diameter = 2+0.4; //mm (m2 + 0.4mm clearance)
 6wall_thickness = 1;//mm
 7// Misc
 8resolution = 100;
 9// End config
10
11// Modeling
12difference(){
13    cylinder(length,diameter/2+wall_thickness,diameter/2+wall_thickness,$fn=resolution);
14    cylinder(length,diameter/2,diameter/2,$fn=resolution);
15   }