How to calculate the chip load in a lathe cnc

Hi, this is a brushed dc servo motor from Bridgeport lathe the original driver is does not working. I get this other driver some months ago for another project, but I am thinking to use it to control the motor.
The typical output current is 12A continuosly and the motor is a 21A max. The driver's manufacter says the driver could work.
What do you recomend?
In a certain time the motor will need of full current?

https://photos.app.goo.gl/AwcDdzbaKCToYBdC7

Regards.