Hi Paul, Great choice of lathe. I got one of these last Nov and really pleased with it. Having upgraded from a manual speed change to this little beauty has been fantastic. I had the same problem as you with the mounting onto a bench. The manual it came with did not detail the imperial thread size and type. I managed to find out by contacting jet and came up with the same answer. It did make mounting it on to the bench top difficult as you can't see the mounting holes you are trying to get the bolts to thread into and can quite easily end up cross threading into the blind tapped holes. Go careful!
One of the selling points I liked was that the tail stock having the marked scale to allow to drill from 0 to 60mm depth. The only problem I found was that with my new 2MT Jacobs chuck when you wind it back to the zero mark, because of the flat tang on the end of the Jacobs chuck 2mt part, the chuck would be ejected automatically at the 17mm mark, so I could not take the fully advantage of the 0 to 60mm travel. I solved this problem but literally cutting off the tang. I now get the full range of movement.
Have fun with it.
Martin