dorotaC#CNC routers. Multiple people say: a drill motor is not made for sideways load. Use a separate ball bearing for the spindle.
Why?
Doesn't a drill motor have a ball bearing already?
Triddle@dcz Hi. Not an expert. Some motors have a sintered bearing (basically just a brass ring) at one or both shaft ends. Even one ball bearing is not sufficient, you need a roller bearing at each end of the shaft because of the sideways pressure.
The shaft needs to be thick enough to take the load without bowing.
An extra bearing below the motor can take the sideways load and protect the motor against such issues.
But get advice from someone who really knows.