Roto Matic
The first was the dark green Roto Matic 800, this had no wheels ,the top attached with 2 knurled knobs, this was made in 1952 and 53, in 54 the same machine was made in red and grey, an optional wheeled dolly was offered, this was a simple thing looking like an X that clipped on the bottom, in 1955, this machine became the 800-A, it differed in that it had clamps on the sides to hold the top on, the dolly was a much nicer round 1 piece unit with a rubber bumper and the switch was moved high up on the side of the machine....oh yes, sometime in 54 the motor was changed from the 4250 Lamb to the more modern and more powerful 4450 Lamb, if im not mistaken the 900 machines came out in the fall of 56,after that different versions of the 800 were sold as a lower priced machine.such as the 860 you mention.