| Brian's 1950's Sphere Lathe (clone of Atlas aka Sears Craftsman) | |
| Acknowledgments to Tony Griffiths for the historical background | |
| The Atlas lathe | |
| The
very first 10-inch (10.25" x 24.5") Atlas lathe
(illustrated at the bottom of this page) was introduced during 1934; the
machine was considerably more robust than the two-year old Series
-9 it replaced, especially in the area of the headstock where a
completely redesigned casting resulted in a much stiffer structure. A
conventional backgear assembly was bolted to the back of the headstock
and the spindle-speed range, with a two-step pulley on the motor and
countershaft, a very useful 28 to 2072 r.p.m. In general appearance the
rest of the machine did not differ greatly from the original model and a
further two years passed before the next revision, in 1936, addressed
many of the machine's remaining weaknesses - this model being
almost the final evolutionary form of the machine (apart from the power
cross feed Model 10-F introduced a year later) and was to continued in
production largely unchanged until the late 1950s when it was replaced
by a heavily-redesigned 12-inch version. The 1936 lathe was enormously improved in almost every area: the feet were greatly extended to help stiffen the bed, the saddle was given tapered arms and the compound slide redesigned on more robust lines and fitted with zeroing micrometer dials. The headstock was further stiffened and the tailstock, strengthened and redesigned so as to "reach" further over the carriage, was provided with a "dip oiler" (often holding white lead) to lubricate the back centre. The changewheel cover, now in cast aluminum (or plastic for some markets) was held fast by a spring-loaded catch and some versions, especially those intended for use in educational and training establishments, were available with complete guarding of the drive belts. The swing of the lathe was 101/4" and between centres capacities of 18", 24" , 30" and 36" were all available. 16 spindle speeds were provided, from approximately 28 to 2072 rpm, depending on the motor used. The spindle was bored through 25/32", held a 3 Morse taper centre and was provided with a useful 60 hole, plunger-locked indexing device; the tailstock was No. 2 Morse. The backgear assembly was bolted to the back of the headstock, so allowing the machine to be offered without this facility in simpler "utility" versions at a lower price. Two designs of countershaft were offered, both with grease-cup lubricated Hyatt roller bearings held within simple but ingenious-designed self-aligning housings: the "Horizontal" bolted to the bench at the back of the lathe (and made the whole assembly rather deep front to back) and the "Vertical" that was attached to the back of the bed and headstock and made a much more compact and portable unit.
Picture of 1936 Lathe - here |
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| The copies | |
| Novel use was made of new materials and some models,
especially those either manufactured or assembled in England under the
"Sphere", "Halifax" and "Acorntools"
labels had significant parts made from an early form of black plastic -
whilst on all models the gearwheels, handwheels, pulleys, clasp nuts and
other small parts were made from "Zamak", a combination of aluminum,
magnesium, copper and zinc that was pressure injected into
hardened-steel dies. Interestingly, the English versions, Sphere and
Halifax, did not just sport different badges but had either the
"maker's" name cast into the bed foot together with the claim
"British made" (Sphere) or considerable mechanical differences
(Halifax) showing that they must either have been specially constructed
by Atlas or copied or manufactured under licence in England. The Halifax
in particular incorporated several significant changes: a screwcutting
gearbox of the post-1958 type - but fitted to the earlier 10F-type
lathe, tumble reverse (like the USA Craftsman model) instead of the
leadscrew "reversing gearbox", plastic pulleys and a wider
cross slide. The Sphere also had the wider cross slide and used plastic
not only for the matching headstock and countershaft pulleys but
also for the changewheel and headstock covers and even, on some models,
for the leadscrew reversing gearbox casing; unlike the Atlas it had only
one bolt holding down the tailstock end of the bed, rather on the lines
of the Raglan Little John, with which it shares the clasp nuts and a few
other minor apron parts - Raglan obviously saving themselves the cost of
expensive new dies by adopting the readily-available and inexpensive
American components.
The Sphere, like the Halifax was still very recognizably an Atlas design, but with several interesting changes to the specification and materials used in the construction: the cross slide was wider and on some of the changewheel-equipped models the casing of the leadscrew reversing gearbox was made in a hard black plastic, a material also used for the gear-case and headstock covers as well as the double-step pulley on the countershaft and the two matching 4-step pulleys on countershaft and headstock.
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| My Lathe | |
| My lathe has 24.5" between centres
Picture of the headstock This shows the non-stock screwcutting gearbox and the tumble reverse. The clutch is operated by the lever on the end of the top pulleyshaft. The clutch is made from a motorcycle brake!! The the brake is on the lathe turns, to stop it the brake is released. I can see other uses for using brakes as a clutch - like worn out disk rotors and old calipers:)) View from the tailstock Also visible is the vertical table which goes on the powered compound slide |
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