I've also begun work on redoing the Z axis.
Before I get too far there is still one little thing that needs doing, setting the value of the extrusion rate in firmware for the motherboard, E_STEPS_PER_MM.
For the standard Mendel with a splined shaft this value is 0.706, while Adrian B. has set this to 2.0 for his geared extruder, though I found out last night that this number is wrong, its too low.
First I had read this blog post
After which I had to ask Adrian if this is equation he used, which it isn't, instead Adrian says that its
1 / (PI . Dpw / Stepper steps) x ((ratio of filament in to nozle dia or Fd / Nd)squared)
PI = 3.14159265
Dpw = 5mm
Stepper steps = 400
Fd = 3mm
Nd = 0.5mm
Comes to 0.707 which is wrong, so I fiddled the equation a bit to come to
((PI x Dpw / Stepper steps) x ((ratio of filament in to nozle dia or Fd / Nd)squared)) / 2
I get 0.706858, and the note in the firmware says its emperically adjusted, so by taking 3sf past the dp you get 0.706.
I don't know how correct this is yet, so i'll update the wiki later