diff --git a/follow_focus.py b/follow_focus.py
index 60a0c15..7663648 100644
--- a/follow_focus.py
+++ b/follow_focus.py
@@ -39,6 +39,7 @@ gear_gap=0.2
 gear_offset=0.5
 large_gear_diameter=8.5
 gear_thinkness=10
+sg_teeth=11
 
 # Other
 mount_gap=2
@@ -70,6 +71,7 @@ support_x = (support_y-b)/slope
 
 lg_x=support_x-stepper_center[0]
 lg_y=support_y-stepper_center[1]
+lg_radius = (math.sqrt(lg_x**2 + lg_y**2)-sg_teeth*mod/2)
 
 def findRodInter(n_x, n_y):
     p = Point(center_x, center_y)
@@ -155,7 +157,7 @@ lid = lid.faces('>Z[1]').workplane().center(stepper_center[0], -stepper_center[1
                                     .circle(5).extrude(lid_thicknesss-wall_width)
 lid = lid.faces('>Z[0]').workplane().circle(5/2).cutThruAll()
 
-base = base.faces('<Z[1]').workplane().center(lg_x, lg_y).circle(26.5).cutBlind(-gear_thinkness-gear_gap)
+base = base.faces('<Z[1]').workplane().center(lg_x, lg_y).circle(lg_radius+2*mod).cutBlind(-gear_thinkness-gear_gap)
 base = base.faces('<Z[2]').workplane().hLine(support_radius, forConstruction=True)\
                                       .threePointArc((-support_radius,-support_radius/2),(0,support_radius))\
                                       .polarLine(support_radius, -slant_degree)\
@@ -200,12 +202,12 @@ lid = lid.faces('<Z[0]').workplane().circle(m3_head_diameter/2).cutBlind(-m3_hea
 
 # Gears
 l_gear = cq.Workplane('XY').gear(SpurGear(module=mod,
-                                          teeth_number=63,
+                                          teeth_number=math.ceil(lg_radius*2/mod),
                                           width=gear_thinkness,
                                           bore_d=large_gear_diameter))
-l_gear = l_gear.translate((21+stepper_center[0],20.15+stepper_center[1],(gear_thinkness+gear_offset)/2))
+l_gear = l_gear.translate((lg_x+stepper_center[0], lg_y+stepper_center[1], (gear_thinkness-gear_gap)/2))
 s_gear = cq.Workplane('XY').gear(SpurGear(module=mod,
-                                          teeth_number=11,
+                                          teeth_number=sg_teeth,
                                           width=gear_thinkness))
 
 
@@ -217,7 +219,7 @@ copy = s_gear.faces('<Z[0]').workplane().vLine(tab_distance, forConstruction=Tru
                                                                         .close().cutThruAll()
 s_gear = s_gear.faces('<Z[0]').sketch().circle(shaft_diameter/2).finalize().cutThruAll()
 s_gear = s_gear.add(copy)
-s_gear = s_gear.translate((stepper_center[0],stepper_center[1],(gear_thinkness+gear_offset)/2))
+s_gear = s_gear.translate((stepper_center[0],stepper_center[1],(gear_thinkness-gear_offset)/2))
 
 # Render
 show_object(base, name='Follow Focus Base')