Calibrate dual extruder with heated bed

[caddy-cool 0]

Hi guys do you have any tips on calibrating the dual extruders to the heated bed? I assume you just do as the wiki says except you don't adjust the 4 corners you use the 3 adjusters?

It is being hampered by backlash in the z drive causing the bed to drop just beyond the limit switch. Anyone know how to remove the play in the Z axis?

 

[caddy-cool 0]

Solved it by printing a z axis adjuster on works ultimaker