How much maximum load in $kg$ stepper motor can take

Below is stepper motor detail. Motor is connected with lead screw size of lead screw is M$12-1$ and length is $30mm$ Thread size: ISO $965/26$H$-6$g$.?$

Standard Operating Conditions:

$12$ V DC Constant $(1)$ Rated Voltage

No$.$ Of Phases : $2$ Phases $(3)$ Excitaion Method

Phases Excition Bipolar Method

Operating Temperature Range : $0C+55C$:$0C+55C$

Storage Temperature : $0C+55C$:$0C+55C$

Electrical Specification :

Coil Resistance : $40+-7\%$

Step Angle : $0\mathrm{.}077\frac{}{?}$ STEP

Insulation Strength : $100V$ AC For One Second $3mA($Max$.)$

Insulation Resistance : $10\mathrm{.}0M($min$.)($VC $100$V$)$

Max. Slewing Frequence : $1800$ pps $($min$.)($No$-$load$)$

Max. Starting Frequence : $1000$ pps $($min$.)($No$-$load$)$

$3.$ Mechanical Specification

Transmission Ratio : $1$:$233$

Output Torque : $800gf-cm($Min$.)($AT $500pps,$ At $12VDC)$

GEAR SEPARATION FORCE : $3kg($MIN$)$