My Grizzly G4000 9x19 lathe. I have made several modifications to this lathe. They include a tumbler reverse, PMDC variable speed motor, gearing changes, electronic carriage stop, taper attachment, a square four-bolt base for the compound and set screws to lock both of the compound slides.
This is my Grizzly G0463 small mill/drill. You can see the rotary table that I purchased. This is an absolutely necessary accessory for anyone who intends to do serious machine shop work. I use it for nearly every project. It's a 6 inch model and just a bit big for this mill but I have not encountered any problems. I did have to slightly modify the mounting holes to fit the mill's table.
I've converted the lathe to a PMDC motor using a treadmill motor and a KBMD-240D controller with a FWD-BRK-REV switch. This is a huge and inexpensive improvement.