I was curious about this as my spindle was starting to sound a little noisy. Also, I wanted to get a more standard set of tools that I could use in the future and BT30 fit that criteria. But, I really want to have a power drawbar. Manual tool changes are not a step forward in my opinion.

I went and looked at the diagram for the 1100MX and noticed all the casting part numbers were the same as the 1100's. There was also a part number for the MX spindle cartridge (#39590). I called Tormach and asked about the availability for non MX owners to purchase it and was told it was not available for purchase at this time. This was after telling them what machine I was using it for of course. The other major detail about the fit on the 1100 I was told was that the bore in the casting was also a different size. I imagine it is larger.

I am only posting this because I had thought about this all week, shopping for Chinese spindle options, reading lots of forum posts, googling, etc.. I should have started with Tormach and then looked elsewhere. I hope this information is helpful to others and that if anyone has a way to purchase the spindle they post it here. Especially if they are doing the conversion.