Created with Customizer: http://www.thingiverse.com/apps/customizer/run?thing_id=54024

Using the following options:

HoleFlatThickness = 0
TaperPercentage = 20
ScrewHoleDiameter = 0
RingWidth = 2
KnobHeight = 16
CapType = 1
RingMarkings = 0
NotchedShaft = 0
HoleDepth = 14
ShaftLength = 0
HoleDiameter = 4
Knurled = 1
KnobDiameter = 11
ShaftDiameter = 10
Pointer2 = 1
Pointer1 = 0
TimerKnob = 0