I've been pretty quiet here since i joined. Been busy learning and converting.
I picked up a j head back in january for $1600. Turned out to be a very good machine, it didn't need much except for cleaning and maintanance. I decided on stepper motors for simplicity. (1200oz/in) I used the original y-axis bearing mount and located it inside the box. For the x-axis, i made a new bearing mount that is welded/machined into the box and used angular contact bearings on both axis. The power supply, b/o board and motor drives are located in the column. It made for a nice install but it's a bit of a pain to work on anything in there. I had some problems loosing steps though. I was able to get 170ipm but detuned it to 120ipm. It would be fine for a while then it would loose steps on startup or after the motors were good and hot. It only lost steps once while machining at a 10ipm feed rate, i don't know what that was about but it seems to have solved itself. I've loaded some pics of the conversion and a pic of my first part.