Calibration Problem

I use Parametric Better Coin Calibrator (http://www.thingiverse.com/thing:11270)

Pls see attached image for size measurement.

The problem is when i use value of coin hole (23.95mm) to calibrate both X and Y. After insert new value, i got coin hole almost 23.95mm but the edge (47.90mm) is exceeded 1-2 mm. So, i try again using value of Edge to calibrate (47.90mm). After calibrate i got edge value calibrated but Coin hole short by 1 mm (Coin can't insert).

What i need to do to get calibrated both Edge (47.9mm) and Coin Hole (23.95mm)?

I'm using Mendel with Marlin 1.0 (Slic3r 0.72b) setting as below
- Machine : Mendel
- Firmware : Marlin 1.0
- Extruder : J-Head 0.5mm
- Program : Slic3r 0.72b (Setting below)
; layer_height = 0.3
; perimeters = 1
; solid_layers = 1
; fill_density = 1
; nozzle_diameter = 0.5
; filament_diameter = 2.9
; extrusion_multiplier = 1
; perimeter_speed = 30
; infill_speed = 60
; travel_speed = 130
; extrusion_width_ratio = 0
; scale = 1
; single wall width = 0.70mm

This sounds horrible, but a pair of decent calipers should be about $20. Go buy some from amazon or from a local hardware store. Don't spend $50, you can get them for under $20. I tried doing what you're doing, and it works... eventually. But you'll go through $10 worth of plastic before it works. Its worth the investment for the tools you need. If you calibrate it all with calipers (extrusion length, filament width, x y & z steps), then slic3r will do its job and just work.

calibrate your x,y,z steps / mm in firmware with actual movements of the machine not to the parts you create. There are other factors like amount of plastic extruded that can change the size of parts but have nothing to do with steps/mm.