This confusingly-named range of lathes were all based on a single backgeared and lathe - itself very similar to the late-model TDS but without the power shaft for sliding and surfacing feeds. All models appear to have had the same headstock assembly with 8 spindle speeds of: 60, 85, 135, 200 in backgear and 410, 570, 930 and 1350 in direct drive.  The  TDS-1LS and type 250 were the most highly-specified models with backgear and a power sliding feed by chain or belt-driven leadscrew (but not screwcutting), the TDS-5BG was backgeared but with the power feed removed and the TDS-3MW was a special plain-turning metal lathe but fitted with an outboard bowl-turning rest adapted from the TDS 6WL dedicated wood lathe.  On the seldom-seen Type 250 and TDS-3MW models the drive could be flicked in and out by a dog clutch, the operating handle of which was positioned in the lower right-hand corner of the headstock's front face.