Parmar Lathes
Parmar lathes were made by the Parmar Mechanic Works in Surendranagar, Gujarat, India. By the early 1970s a range of machines was being offered including the heavy-duty Pinakin-250 (shown at the bottom of this page) and a group of models based closely on the design of Colchester lathes as manufactured from the mid 1930s until the late 1950s. The latter set consisted of two geared-head models, the straight-bed 6" x 24" HMP-1 and gap-bed 6" x 42" HMP-2 and the cone-pulley (flat-belt) drive 6.5" x 24" MKP-1 and the 6.5" x 42" MKP-3. Apart from their drive systems (the belt lathes were fitted to under-drive stands, all shared the same major mechanical parts and were . In addition, a version of both geared-head lathes was offered with the centre height increased to 6.5 inches and a speed range of 46 to 1000 r.p.m. instead of the ordinary 25 to 500 r.p.m.
Although the stand was a modern cabinet type and the castings all custom-made (and different somewhat in shape from then originals), the layout of the controls was identical with the distinctive "slide-and-lift-lever" apron employed as found on all Colchesters until the advent of the single lever "safety-apron" in the late 1950s. One development not adopted on the geared-head Parmar lathes was the use of expensive, high-precision Gamet bearings in the headstock; instead, simple adjustable bronze bearings, together with a ball race to take end thrust, were used. Hardened, ground and bored through to clear 13/8", the headstock spindle was fitted with a step-down No. 3 Morse taper sleeve and threaded 2.125" x 8 t.p.i. on its nose. Inside the headstock and lubricated by splash, the shafts and gears were not hardened and ground, but simply made from good quality steel, the use of a 1.5 h.p. (instead of a 3 h.p. as on the Colchesters) ensuring that lathe could not be overworked (the belt drives versions were restricted to just 1 h.p.). Oddly, the flat-belt drive models - which must have been the cheaper option - were equipped with taper-roller bearings headstocks. Using a conventional backgear assembly behind the headstock, on these versions the drive to the screwcutting gearbox was through an externally-mounted tumble-reverse mechanism, a common arrangement on Indian lathes at the time when for decades other makers had placed it on the inside of the headstock, with the shaft supported at both ends.
Also altered from the Colchester specification (on all versions) was the pitch of the leadscrew, from 6 to 4 t.p.i. Although the threading range from the dual imperial/metric box screwcutting gearbox remained the same, with 45 inch pitches from 4 to 120 t.p.i. and 12 metric from 0.25 to 6 mm, the power feed rates were altered, being slightly slower at 0.0019" to 0.053" per revolution of the spindle longitudinally. However, being set at 1/6th the sliding rate, rather than the usual 1/2, the cross-feed rates were very much finer and ranged from an ultra slow 0.00031" to a very slow 0.0088".
Fitted with micrometer dials graduated to show intervals of 0.001" the compound slide assembly included an indexing 4-way toolpost as part of the regular equipment.
Included with a newly-delivered lathe was a catchplate, two Morse centres, a thread-dial indicator, a number of extra changewheels to extend the threading range and the necessary spanners.