Use these to test extrusion accuracy and thread width.
In Slic3r, you should set "detect thin wall" to on. In kisslicer, there appears to be gaps, depending on style settings. For the 0.4 model, the following Style profile in kisslicer produces unexplained gaps: layer_thickness_mm = 0.1 extrusion_width_mm = 0.35 num_loops = 5 skin_thickness_mm = 0.8 infill_extrusion_width = 0.5 infill_density_denominator = 10 stacked_layers = 1 use_destring = 1 use_wipe = 1 loops_insideout = 0 infill_st_oct_rnd = 1 inset_surface_xy_mm = 0.175 seam_jitter_degrees = 0 seam_depth_scaler = 1

While the following Style profile in kisslicer does not produce gaps: layer_thickness_mm = 0.25 extrusion_width_mm = 0.5 num_loops = 3 skin_thickness_mm = 0.8 infill_extrusion_width = 0.5 infill_density_denominator = 4 stacked_layers = 1 use_destring = 1 use_wipe = 1 loops_insideout = 0 infill_st_oct_rnd = 1 inset_surface_xy_mm = 0 seam_jitter_degrees = 0 seam_depth_scaler = 1

Use these to test both your slicer settings, as well as your extruder settings and thread width.
The concept is from Vladimir Mariano and Kacie Hultgren.
http://youtu.be/Z8ZthdEifOo
http://makersguildfc.com/2013/12/29/replicator-2-thread-width/