I am trying to calibrate my delta printer with mixed results. I have 
squared the towers and leveled the bed to the best of my available means. 
From there I am using David Crocker's Delta printer least-squares 
calibration calculator found at 
https://escher3d.com/pages/wizards/wizarddelta.php with G30 probing from 
5mm above bed height to get the height error. I am using a StrainEffector 
V1.3, Azteeg X5 mini V2, and Haydn Huntley's magball delta arms (288.27)

Where I am have problems is repeatability I have pasted below a copy of 
commands I send that the results.

SENDING:G28
SENDING:G0 X0.00 Y0.00 Z5.00, G30 F150, G30 F150, G30 F150, G30 F150, G30 
F150
SENDING:G0 X0.00 Y100.00 Z5.00, G30 F150, G30 F150, G30 F150, G30 F150, G30 
F150
SENDING:G0 X86.603 Y50.00 Z5.00, G30 F150, G30 F150, G30 F150, G30 F150, 
G30 F150
SENDING:G0 X X86.603 Y-50.00 Z5.00, G30 F150, G30 F150, G30 F150, G30 F150, 
G30 F150
SENDING:G0 X0.00 Y-100.00 Z5.00, G30 F150, G30 F150, G30 F150, G30 F150, 
G30 F150
SENDING:G0 X-86.603 Y-50.00 Z5.00, G30 F150, G30 F150, G30 F150, G30 F150, 
G30 F150
SENDING:G0 X-86.603 Y50.00 Z5.00, G30 F150, G30 F150, G30 F150, G30 F150, 
G30 F150
SENDING:G0 X0.00 Y0.00 Z5.00, G30 F150, G30 F150, G30 F150, G30 F150, G30 
F150
Z:5.0500
Z:4.9850
Z:4.9850
Z:4.9825
Z:4.9825

Z:3.5300
Z:3.5275
Z:3.5275
Z:3.5275
Z:3.5275

Z:4.9425
Z:4.9575
Z:4.9550
Z:4.9575
Z:4.9575

Z:5.0300
Z:5.0325
Z:5.0375
Z:5.0400
Z:5.0475

Z:4.7975
Z:4.7975
Z:4.8000
Z:4.8050
Z:4.8025

Z:5.1025
Z:5.1025
Z:5.1025
Z:5.1050
Z:5.1050

Z:5.0150
Z:5.0125
Z:5.0150
Z:5.0100
Z:5.0150

Z:4.9550
Z:4.9575
Z:4.9575
Z:4.9600
Z:4.9675

Not much of a difference but still a difference between the first

G0 X0.00 Y0.00 Z5.00, G30 F150, G30 F150, G30 F150, G30 F150, G30 F150
(Z:5.0500
Z:4.9850
Z:4.9850
Z:4.9825
Z:4.9825)
and the last

G0 X0.00 Y0.00 Z5.00, G30 F150, G30 F150, G30 F150, G30 F150, G30 F150
(Z:4.9550
Z:4.9575
Z:4.9575
Z:4.9600
Z:4.9675)

Then the difference when I G28 between them.

SENDING:G28
SENDING:G0 X0.00 Y100.00 Z5.00, G30 F150, G30 F150, G30 F150, G30 F150, G30 
F150
SENDING:G28
SENDING:G0 X86.603 Y50.00 Z5.00, G30 F150, G30 F150, G30 F150, G30 F150, 
G30 F150
SENDING:G28
SENDING:G0 X X86.603 Y-50.00 Z5.00, G30 F150, G30 F150, G30 F150, G30 F150, 
G30 F150
SENDING:G28
SENDING:G0 X0.00 Y-100.00 Z5.00, G30 F150, G30 F150, G30 F150, G30 F150, 
G30 F150
SENDING:G28
SENDING:G0 X-86.603 Y-50.00 Z5.00, G30 F150, G30 F150, G30 F150, G30 F150, 
G30 F150
SENDING:G28
SENDING:G0 X-86.603 Y50.00 Z5.00, G30 F150, G30 F150, G30 F150, G30 F150, 
G30 F150
Z:5.0625      (Z:3.5300)
Z:5.0600      (Z:3.5275)
Z:5.0600      (Z:3.5275)
Z:5.0625      (Z:3.5275)
Z:5.0650      (Z:3.5275)

Z:5.7650      (Z:4.9425)
Z:5.9450      (Z:4.9575)
Z:6.0525      (Z:4.9550) 
Z:6.0450      (Z:4.9575)
Z:6.0475      (Z:4.9575)

Z:5.0850      (Z:5.0300)
Z:5.0900      (Z:5.0325)
Z:5.0925      (Z:5.0375)
Z:5.0925      (Z:5.0400)
Z:5.0925      (Z:5.0475)

Z:4.8975       (Z:4.7975)
Z:4.9075       (Z:4.7975)
Z:4.9000       (Z:4.8000)
Z:4.9100       (Z:4.8050)
Z:4.9125       (Z:4.8025)

Z:5.1025       (Z:5.1025)
Z:5.1225       (Z:5.1025)
Z:5.1250       (Z:5.1025)
Z:5.1250       (Z:5.1050)
Z:5.1275       (Z:5.1050)

Z:5.3350       (Z:5.0150)
Z:4.9925       (Z:5.0125)
Z:4.9300       (Z:5.0150)
Z:4.9275       (Z:5.0100)
Z:4.9300       (Z:5.0150)


I have also tried sending G90 before I started to ensure I am using 
absolute positioning, but still getting the kind of results I have shown 
above. Any help or insights would be greatly appreciated.

Thanks,
  Christopher