Delta Printer print sizes wrong

Plumpeken

Hello, I am new to delta 3D printers. I bought a cheap kit that is working really well now (FLSUN kossel mini) But when printing a calibration cube the width and depth are 1mm to large but the height is basically perfect. on a cartesian style printer you would just need to change the steps per mm but when I tried doing that for the X and Y values it just made the X and Y motors go slower so the next print was lops sided. That makes sense to me know, but I still need help finding out how to dial the width and length down a bit.
Thanks,

Repetier

In deltas the diagonal rot length is responsible for the xy size. Unfortunately if you change that you get a ump/dome in the center, so you also need to adjust horizontal radius to correct the resulting geometry error.

Plumpeken

Repetier wrote
In deltas the diagonal rot length is responsible for the xy size. Unfortunately if you change that you get a ump/dome in the center, so you also need to adjust horizontal radius to correct the resulting geometry error.

Where would I change the DELTA radius? I don't see an already existing value.
Thanks for the reply

#define DELTA
// Make delta curves from many straight lines (linear interpolation).
// This is a trade-off between visible corners (not enough segments)
// and processor overload (too shi many expensive sqrt calls).
#define DELTA_SEGMENTS_PER_SECOND 160
// Center-to-center distance of the holes in the diagonal push rods.
#define DELTA_DIAGONAL_ROD 218 // mm
// Horizontal offset from middle of printer to smooth rod center.
#define DELTA_SMOOTH_ROD_OFFSET 150 // mm
// Horizontal offset of the universal joints on the end effector.
#define DELTA_EFFECTOR_OFFSET 24 // mm
// Horizontal offset of the universal joints on the carriages.
#define DELTA_CARRIAGE_OFFSET 22 // mm
// Effective horizontal distance bridged by diagonal push rods.
#define DELTA_RADIUS (DELTA_SMOOTH_ROD_OFFSET-DELTA_EFFECTOR_OFFSET-DELTA_CARRIAGE_OFFSET)

Repetier

Don't try it in configuration.h - that is just a pain to recompile that often. Values are stored all in eeprom so you can change it from Repeteier-Host/server using the eeprom editor. There you have "Diagonal rod length" and "Horizontal rod radius at 0,0".

In config it is

#define DELTA_DIAGONAL_ROD 345 // mm/** \brief Printer radius in mm, measured from the center of the print area to the vertical smooth tower. Alternately set this to the pivot to pivot horizontal rod distance, when head is at (0,0)*/

#define PRINTER_RADIUS 124
At least in our firmware. I think you are using a different one, so that is the wrong place to ask then.