email: tony@lathes.co.uk
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Celtic Lathes by Mondiale
Mondial Simplex Lathes    Celtic 14   Celtic 17    Celtic 20   
Mk. 2 Celtic Lathes

Mondial and Simplex Manuals are available from store.lathes.co.uk


Mondiale machine tools were made by Mondiale S.A. Constructions Mechaniques of Vilvorde-Bruxelles in Belgium. Although some carried badging identifying them as made by Mondial, others did not and instead used a variety of model names including: Simplex,  "Accura Simplex", Celtic, Gallic, Nordic and Standard. Their lathes of the late 1950s and through the 1960s were based on much-improved developments of their earlier "Simplex" models and included the "Celtic" and "Gallic" ranges all of which, despite some shortcomings of capacity specification, were considered to be very well engineered and soundly constructed. The original Celtic models were built as the Model "12" (6-inch centre height), Model "14" (79/32" centre height), Model "17" (81//1.9 H.P. for heavy-2" centre height) and the Model 20 (10" centre height).  Later versions lost their unpretentiously honest 1950s lines and simple rod control levers and were replaced by mechanically very similar machines with squared-off styling and flat control levers that ended in distinctive, triangular-shaped tabs.
A robust machine, the original Celtic "12" had a 6-inch centre height, either 20 or 32 inches between centres and was intended for general workshop use, engineering training establishments and light production use. The lathe was mounted on two cast-iron plinths spanned by a deep chip tray and with option of two storage cupboards between the legs.
Divided and stiffened by two internal walls into 3 compartments, the headstock held an oil-bath lubricated gearing set equipped with an unusual dog-clutch in the form of a male and female "sprocket" arrangement. The central section, which contained the twin drive pulleys, and was sealed from the front (lubricant-holding) compartment to keep the V-belts oil free while the left-hand housing held the oil-immersed reversing gears that drove out to a train of screwcutting changewheels. At 1.04 inches the bore of the No. 4 Morse taper, Timken taper roller-bearing headstock spindle was markedly inferior to the 1.5" of the similarly-sized Colchester Student; the spindle was driven by 2 V belts from a 4-speed gearbox mounted inside the left-hand cabinet plinth and could be specified with either a 45 mm-diameter, 3 mm-pitch thread on its nose or (standard on the high-speed model) a much safer and more rigid American long-taper L00 fitting. The spindle-speed gearbox was operated by a large chrome-plated lever on the front of the stand and equipped with oil-splash lubricated, induction-hardened gears running on ball-bearing-supported, hardened and splined shafts. Bolted beneath the gearbox was a push-button controlled electric motor fitted with 2 speeds as standard; according to the buyer's needs this could be specified as a low-power 1.3 - 0.9 H.P. for educational and training establishments, 2 - 1.6 H.P. for general-purpose use or 3 - 1.9 H.P. for the special "high-speed" model. Combined with the single-lever operated headstock-mounted "backgear" assembly the drive gave a total of 16 spindle speeds that spanned 35 to 1500 rpm on the standard models and 45 to 2000 rpm on the high-speed version. Although a spindle clutch was not available on any of the models the high-speed lathe was fitted with a powerful foot-operated brake on the drive pulley of the speed-change gearbox; it was applied by a full-length bar between the stand legs with its initial movement arranged to switch off the motor.
Of a design also seen on the beautiful American Wade No. 7 precision bench lathe, the V-ways of the bed were  asymmetric - front V was both laid back at a shallower angle than normal and made especially wide while the rear surface was narrower and, in order to better absorb tool thrust, set at a steeper angle  Although not hardened (a process restricted to the extensive options' list) the bed was of robust construction and relatively deep in relation to the machine's centre height. No gap was fitted, nor could one be specified as an optional extra.
With every thread or feed selection made by rotary levers (and a consequent absence of sliding controls) the oil-bath screwcutting and feeds box (with hardened gears) could be completely sealed against the ingress of dirt and swarf. By using just the ordinary set of changewheels the box was able to generate 54 English pitches (from 96 to 1
5/8 t.p.i.) and 27 metric (from 0.25 to 10 mm pitch) - a specification rather better than the 45 English and 12 metric pitches available on the standard Colchester Student. The sliding and surfacing feeds totalled 54 from 0.0021" to 0.128" per revolution of the spindle on longitudinal travel and from 0.0011" to 0.064" on the cross feed. With different changewheel set on the quadrant arm a complete range of diametral and module pitches could also be produced and the 5-segment screwcutting chart included these thread sets in its layout. The 4 t.p.i. leadscrew was ground finished for accuracy and its bronze engagement clasp nuts made adjustable for backlash; the power feeds were taken to the apron by a separate keyed shaft working though a torque-limiting coupling that also, very usefully, permitted work to be turned against stops.
With its double-wall construction, oil-bath lubrication and ingenious mechanical design (borrowed from larger Celtic lathes and long a tradition of the maker) the all-helical-geared apron was, some might argue, over-engineered for the lathe's capacity. The drive shaft from the gearbox transmitted its power through a worm and wheel to a shaft that passed vertically though the centre line of the casting; at the top of the shaft a double-sided dog clutch (operated by a very large combined selection and engagement quadrant lever on the face of the apron) moved up or down to select power surfacing and sliding feeds respectively - as reference to the illustrations below will make clear. A robust and reliable piece of engineering its feeds engagement mechanism used a push-pull plunger to select sliding or surfacing with a flick-in-and-out the lever to engage or disengage the feed. Pushing the plunger and turning it blocked the option to select both feeds at once,
Entirely conventional the saddle was without a T-slots in its top surface and carried a compound slide rest with proper taper gibs that were adjustable, with the usual sensitivity, by a single screw at the front. Two plain non-T-slotted cross slides were available, both with a travel of 6.75": a standard version - unfortunately shorter than the slide that it ran on and with a cast extension cover at the rear to protect the feed screw - and a full-length one able to accommodate a rear-mounted toolpost and its support block. The top slide could be rotated only 45 degrees in either direction but was supplied complete with an indexing (through 8 positions) 4-way toolpost at no extra cost.
Perhaps the weakest point of the lathe's specification, the tailstock had an unhardened 1.438"-diameter barrel that was  "microfinished";  its travel was short at 3.375 inches (A Colchester Student has nearly 6 inches) and the Morse taper was only a No. 2 when a No. 3 would have been more in keeping with the rest of the machine. The top section could be offset in the usual way for taper turning and the clamping lever was conveniently placed at the very top of the casting.
In short-bed form the lathe weighed 1230 lbs and as a long-bed 1520 lbs..

6-inch centre height by 20 or 32 inches between centres Model "12"  Celtic by Mondiale

High-speed Celtic 12 with L00 spindle nose and the optional storage cupboard between the stand plinths.

Headstock from the High-speed version of the Celtic 12. Stiffened by two internal walls into 3 compartments that nearest the spindle nose held the oil-bath lubricated reduction gearing set (with an unusual dog-clutch in the form of a male and female "sprocket" arrangement) the centre part contained the twin drive pulleys (sealed to keep the V belts oil free) while the left-hand section held the oil-immersed reversing gears that drove out to the train of screwcutting changewheels.


A picture of the Model 20 but still applicable to the much smaller Model 12 - the V ways of the bed were of a design similar to that first seen on the beautiful American Wade No. 7 precision bench lathe where the (asymmetric) front V was both laid back at a shallower angle than normal and made especially wide;  the rear surface was narrower and, in order to better absorb tool thrust, set at a steeper angle.The standard cross slide was considerably shorter than the slides it ran on and was fitted with a cast extension cover at the back to shield the feed screw from swarf.

The drive shaft from the gearbox transmitted its power through a worm and wheel to a shaft that passed vertically though the centre line of the casting; at the top of the shaft a double-sided dog clutch (operated by a very large combined selection and engagement quadrant lever on the face of the apron) moved up or down to select power surfacing and sliding feeds respectively

A 4-speed gearbox, oil-splash lubricated with induction-hardened gears running on ball-bearing-supported, hardened and splined shafts was fitted into the headstock-end cabinet plinth. Bolted beneath the gearbox was a push-button controlled electric motor fitted with 2 speeds as standard; this could be specified as a 1.3 - 0.9 HP,  2 - 1.6 HP or 3 - 1.9 HP. 


Mondial Simplex Lathes    Celtic 14   Celtic 17    Celtic 20   
Mk. 2 Celtic Lathes
Mondial and Simplex Manuals are available from store.lathes.co.uk

Celtic Lathes by Mondiale
email: tony@lathes.co.uk
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