The spindle motor on my 33 year old Boxford CNC lathe has struggled to machine steel, although it copes with brass OK. My expert friend has recently upgraded his machine (identical to mine) with a new spindle motor, and I will do likewise.
The new motor is a 750 watt Servo, bought on Ebay from China.
It is more powerful than the original DC motor, small enough to fit the limited space in the 125TCL, and my friend reports that it is performing very well indeed.
Some modifications to the mounting system and drive pulleys and electronic controls will be required.
For reader Tom, who is upgrading a 125TCL as a school project, I include the following photo.