Strange value in Firmware for x/y steps/mm

I have received a new belt (GT2) and 2 new pully’s for the x and y motors.
I have used the belt calculator in repetier, and according the calculation i have to set the steps/mm for both on 80

but i have also calculated the original belt deliverd with the K8200.
T5 belt with 10 teeth pully’s.
the calculation for this configuration should be a value of 64 steps/mm

Then i looked in the firmware, and i saw 2 values of 64.25 ?
can somebody explain where this value comes from?

And if i install the GT2 belt with 20 teeth pully’s is the value of 80 correct?

Yes it works for me (I have pulleys at both ends of the belt).

[quote=“dutchronnie”]Then i looked in the firmware, and i saw 2 values of 64.25 ?
can somebody explain where this value comes from?[/quote]
The value should be 64 indeed. 64.5 must be a corrected value resulting from calibration tests.

[quote=“dutchronnie”]
And if i install the GT2 belt with 20 teeth pully’s is the value of 80 correct?[/quote]

Jep, 80 should be fine.
I used 16 tooth pulleys for my GT2 belt and have set it to 100.
The 64.5 must be a somehow “calibrated” value, just as raby wrote.

cheers,

Christian

If the T5 belt with 10 teeth pully’s need a calibration value, then i suspect that a GT2 belt with 20 teeth also needs a calibration value.
with this value the x and y dimensions are changed, i find it a bit strange.

If the T5 belt with 10 teeth pully’s need a calibration value, then i suspect that a GT2 belt with 20 teeth also needs a calibration value.
with this value the x and y dimensions are changed, i find it a bit strange.[/quote]

The calculated steps of 64 assume that the pulley diameter and belt dimensions are absolutely spot on.
This is not likely to happen. So after some test prints you will find a sligtly other value will make your parts fit perfectly.

OK, that means that after i have installed the T2 belt i must do a calibration of the x and y ax.
I think i install the belt this evening.