email: tony@lathes.co.uk
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Mars "Venus" Lathe - Australia
- also branded as the Conrick, Great Scot and Nextek -

Mars Lathes Home Page

Junior Lathe    Jupiter Lathe    Venus Lathe    Atlas Lathe   Mercury Lathe

A Mars full-range catalogue is available   

If you have a Venus lathe and can contribute photographs,
the writer would be pleased to hear from you

First made during the early 1940s as part of the war effort, the heavily built Mars "Venus"" had a 7-inch centre height and a capacity between centres of  49 inches. The lathe's V and flat-way box section bed - 8 inches wide and braced by diagonal cross ribs - was carried on a pair of identical heavy cast-iron plinths, each with a small storage cupboard.. A detachable gap piece was part of the standard specification and allowed work up to a useful 20 inches in diameter and up to 7 inches deep to be swung on the supplied faceplate (this being finish ground in-situ for perfect alignment). Supplied as part of the standard equipment was a full-length chip tray in pressed steel.
Screwcutting was by changewheels passing though a tumble-reverse mechanism to a traditional Norton-type tumbler gearbox, this holding gears in a chrome-nickel steel lubricated by an oil bath. As just a single tumbler arm was fitted, the range of pitches able to be generated was limited to the following: 6.5, 7, 8, 9, 9.5, 10, 11, 12. 13, 14, 16, 18, 19, 19.5 (?), 20, 22, 24, 27, 28.5, 30, 33 and 36.  With alternative changewheels in place, these could, of course, be extended and also, with a 63t transposing gear, metric pitches as well. A 7/8-inch diameter, 8 t.p.i. acme-thread leadscrew and a separate powershaft were fitted, the leadscrew able to be disengaged when not in use and equipped with a thread-dial indicator as standard. Proper clasp nuts in bronze were used to grip the leadscrew, these being mounted in V-shaped ways with adjustable gib strips. Sliding and surfacing feeds were provided, the finest sliding feed being at the rate of 0.0025" per revolution of the spindle and the coarsest 0.014" per revolution.
A considerable improvement on the apron fitted to the Mars "Junior" model, the apron was doubled sided and held an oil bath. The feeds engagement mechanism was of the "drop-worm" type, a steel worm on the feed shaft engaging with a phosphor bronze wheel connected to a gear drive train. A single quadrant lever both selected and engaged the direction of feed, the design of the mechanism eliminating loading-up during deep cuts and allowing a light, positive engagement and disengagement.
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Set so that the cross slide was to the left of its centre line, the saddle was hand scraped to fit the bed but, unlike the "general-purpose" Junior models had plain wings bereft of T-slots.
With hand-scraped ways, the compound slide rest assembly had a top slide with 3.75 inches of travel and able to be swivelled 30 each side of central. Of the short-length kind (probably intended to allow the fitting of a taper-turning attachment), the cross slide was fitted with a rear swarf guard to protect the feed. Both the top and cross slides were fitted with zeroing micrometer dials which, considering the capacity of the lathe, were on the small size.
Running in phosphor bronze bearings - these being bored in place by a jig attached to the bed - the headstock spindle was bored to allow the clear passage of work up to 1.5 inches in diameter. Finish ground, the spindle was made from a high tensile steel, lubricated by wick feed from reservoirs beneath each bearing and fitted with a ball-race thrust bearing. Bored with a No. 3 Morse taper socket, the spindle was supplied with sleeve adapter that stepped this down to a No.2 Morse. All the rotating headstock parts were dynamically balanced, the makers stating that this would allow spindle speeds of up to 2000 r.p.m.; however, for practical purposes, at 1289 r.p.m., the top speed was much lower with the full range (driven by the recommended 1 h.p. motor)  being, in backgear, 128, 169 and 224 r.p.m. and in direct drive 690, 946 and 1280 r.p.m.
Drive came from a countershaft bolted to the bed at the back of the headstock, the 1.5-inch wide final-drive belt running over three-step pulleys. Instead of a proper right-and-left-hand-threaded turn-buckle and over-centre lever to lock the belt tight, on early versions at least, the weight of the motor alone sufficed for this purpose.
Fitted with a No. 2 Morse taper spindle (rather small for the class of lathe) the tailstock could be set-over on its base plate for the turning of a slight taper; like nearly all lathes from the period, a small reservoir was provided to hold (highly poisonous) white lead, this being applied to the Morse taper centre by dipper rod. Whilst the tailstock was locked to the bed by a quick action lever working a cam-lifted locking plate, unfortunately, the spindle was clamped tight by a slot, cut into the casting being closed down by a screw; a poor system and one that nearly always results in a fractured casting after a long period of use.
A reasonable amount of equipment was supplied with each new Venus lathe including a 4-way toolpost, fixed and travelling steadies,  faceplate, a pair of hardened centres, a headstock step-down sleeve and belts for the countershaft drive-but no electric motor or switchgear.


Mars Lathes Home Page

Junior Lathe    Jupiter Lathe    Venus Lathe    Atlas Lathe   Mercury Lathe

A Mars full-range catalogue is available   

If you have a Venus lathe and can contribute photographs,
the writer would be pleased to hear from you


Mars "Venus" Lathe - Australia
- also branded as the Conrick, Great Scot and Nextek -

email: tony@lathes.co.uk
Home   Machine Tool Archive   Machine-tools Sale & Wanted
Machine Tool Manuals   Catalogues   Belts   Books  Accessories