everettdavis wrote:Did a little digging and found more, but do not know when it was introduced, or officially discontinued. Early M5's Mark 5's didn't have it. Later Mark V 500's didn't have it. Some did. The 1960's Mark VII did.
Support indicated that engineering felt it weakened the table and it was phased out, but before the current owners owned Shopsmith.
Not much help on establishing a date though.
M5 Greenie Owners Manual.png
You will never find it where the red "circle" is. It is on the other side of the table next to the head stock, ie on the left side.
I can also add that my machine from the factory new in 1976 had the two slots. I have a couple of machines from the late 1970's and early 1980's that do not have the slot but then the tables could have been swapped out since I got them used. The casting on them still have the place for the slot.