Gepy have been producing what are arguably the worlds finest revolving centres in Geneva, Switzerland, since 1946. Unique to the design of these live centers are roller bearings that form an integral part of the centre itself. The taper and needle roller bearings bear directly on the completely hardened and ground shaft allowing a larger diameter shaft to be employed without compromising compactness. This produces a centre with little overhang and thus great rigidity. GEPY centres are self adjusting and sealed from the ingress of foreign matter. The maximum eccentricity of the centre is guaranteed to be not greater than 0.002mm due to the careful selection of the rollers and also the special grinding process which ensures the perfect accuracy of the spindle taper. Gepy centers do not carry model identification marks the only mark being “OEL” indicating the screw where lubrication should be applied – should you require help identifying a Gepy centre please email a photograph.
GEPY centres are available in a variety of types including:
• Type P (as illustrated above) with standard 60 degree point • Type COP with reduced diameter point (largely intended for copier work) • Type C with female (inverted) point • Type K with large diameter inter-changeable points (for supporting tubular work) • Revolving centres with interchangeable points • Special design to customer’s specification
GEPY centres are available with the following taper shanks:
In addition to their famous revolving centres GEPY also produce a number of different styles of high precision spindles for milling, drilling and grinding operations. These exquisitely made spindles are highly complementary to Schaublin and Aciera machines and in some instances were supplied by the manufacturers as original equipment. The B8 spindle (right) was supplied as Schaublin part number 70-89.150 (see archive) and has a maximum speed of 15000 rpm. It accepts B8 (8mm horological) collets.
GEPY spindles are supplied in the following diameters and collet types:
• 25mm B8 and F8 15,000 rpm • 11mm F4.5 60,000 rpm • 14mm F4.5 60,000 rpm • 20mm F7 and ESX 12 40,000 rpm • 25mm F9 40,000 rpm • 35mm F16 and ESX 20 10,000 rpm • 35mm W12 also available with Schaublin 70 threaded spindle nose 10,000 rpm
Fritz Studer AG was founded in 1912. The first cylindrical grinding machine produced was for their own use, but a modified version was exhibited at the 1914 National Exhibition in Bern. Studer cylindrical grinding machines made their first commercial appearance at the Basel Swiss Industries Fair in 1918 in the form of the model OA. This was a modified version of the machine Fritz Studer had made for his own use and featured automatic wheel infeed and a patented automatic reversing mechanism which remained in production until the early 1970s.
Today, Studer are part of the Schleifring group and still make superb manual and CNC cylindrical grinding machines.
The Studer OB was the direct successor to the model OA and was produced from the mid 1930s through to the early 1970s. The OB could accept work up to 400mm long and 100mm in diameter. Around 1500 machines were produced and around 160 were imported to the UK with most machines destined for government bodies such as Royal Ordinance and Royal Mail research departments.
By the 1950s the design of the OB was looking rather antiquated, Studer had pioneered the use of hydraulic table transport in 1939 but the OB continued to use the mechanical drive developed before the Great War. What ensured the survival of the OB was its phenomenal versatility. Not only did it have the conventional table and wheel-head movements, but also a secondary wheel-head compound slide with screw or lever operation. This slide was mounted on a swiveling base allowing the wheel-head, which could also be independently angled, to be fed into the job at any angle. The wheel-head could also carry a second smaller wheel on the right hand end of the spindle further increasing the versatility of the machine. A wide range of accessories was available including various work-heads accepting Schaublin W20 collets, internal grinding attachments, work steadies and small part grinding attachments.
Internal grinding on a Studer OB
The versatility of this machine and its compact size continues to make it useful for certain industrial applications today. One firm I know of has a number of OBs, reconditioned at great expense, used in the production of specialist tungsten carbide tools. GEPY also have a number of OBs employed in the production of their excellent revolving centres and precision spindles. Until recently I had a very well equipped OB in my own workshop which was employed in the reconditioning of other machines.
While the OB continued to have a strong niche in the market place, Studer continued the development of their products and in 1939 produced the world’s first cylindrical grinder with hydraulic table transport. The RHU450 and RHU500 were of greater capacity than the OB and are distinctly modern in appearance with close coupled motor drives for both the wheel-head and work-head. As with current Studer models these machines employed plain bearings in the wheel-head.
The model OC, now known as the S20, was designed as the successor of the model OB. This machine had similar capacities to the OB and still employed a mechanical drive to the table but, like the RHU450 and RHU500, had close coupled drives for the work-head (still accepting W20 collets) and wheel-head. The S20 was also fitted with a pull over internal spindle for rapid deployment. The S20 is a current Studer product.
The Studer RM250 production cylindrical grinder was produced in fairly large numbers from 1959 to the 1980s. This superb little machine was designed for the production of small high precision components such as diesel injector needles. The work-head centre height was 60mm with a distance between centres of 250mm. Tables were electro-mechanically driven through a complex array of belts, servos and relays. Various accessories and special equipment was available for these machines such as auto-sizing equipment enabling them to be employed as semi-automated machines.
These machines are generally not suitable for tool-room type work, but none-the-less could prove extremely useful in the amateurs workshop.
Thanks to Dr Peter Clark for the loan of the 1959 catalogue below.
Best known for their cylindrical grinders, in 1946 Studer introduced the FH450 surface grinder. With a grinding capacity of 450 x 150 the FH450 featured hydraulic feeds to both traverses and could accommodate 325mm under the spindle. The machine was discontinued in 1967.
The Schaublin 70 and 102 lathes employ a very similar range of accessories that very ofter are only distinguishable from each other by size, due to this the illustrations are of a mixture of 70 and 102 accessories. Over the years the number of accessories available have been very much reduced. Schaublin’s current accessory range is probably less than a tenth of that available in the 1950s. The catalogues from which the illustrations below are taken can be downloaded from the individual Schaublin 70 and 102 pages.
SV70 B8 milling attachment
Schaublin 102 W12 milling attachment
Milling attachments consists of a vertical slide with an inclinable milling spindle. The milling attachment is designed to clamp to the lathe carriage tee slots and is driven by a 6mm round belt from overhead. These attachments are incredibly useful even when milling facilities are available since so many jobs can be turned and milled in one chucking. This is particularly useful when concentricity is paramount as in horological wheel and pinion milling. Two versions of milling attachments for the Schaublin 70 and 102 exist. The earlier attachments had flat backs while the later ones had “humped” backs and this is generally how they are known. The 70 and 102 items are very similar except in size and in the type of collet employed. Early flat back 70 milling attachments used B8 (horological) collets while the 102 version employed W12 collets and had a speed reduction gearbox fitted to the spindle.
Schaublin 102 W20 “hump-back” milling attachment
Later hump back attachments employ W12 and W20 collets for the 70 and 102 respectively. While humped back versions are obviously more rigid than the earlier attachments both are extremely sturdy and more than fit for their purpose.
SV102 milling attachment speed reduction gearbox
For the SV102, the flat back attachment has some advantages over the later “hump-back” item mainly due to its compactness and built in speed reduction gearbox. The earlier milling attachment is particularly useful for horological milling. On the other hand, the larger collet capacity and higher spindle speeds of the later attachment have distinct advantages for certain types of work. A speed reduction gearbox with a ratio of 4.5:1 was also available for the 102 hump-back attachment.
Early type Schaublin 70 milling attachment with microscope set up for “watchmaking jig boring”
The grinding attachments illustrated elsewhere can also be fitted to the vertical slide as can a microscope and high speed milling and drilling spindle (made by GEPY) enabling jig boring operations to be conducted. In the illustration to the left a Schaublin 70 has been set up with a quick-change headstock and quill with mandrel-type face plate with raised clamps ready for a typical watch-making operation. A microscope is shown in the vertical slide quill-holder for precise positioning of a cutter held in a GEPY quill which replaces the microscope. The headstock quill has a diameter of 35mm, and although Schaublin never said as much, it was designed to be compatible with the Hauser H1 “machine à pointer” and could be transferred from one machine to the other with the work still in place.
SV102 milling vice
Other accessories that could be mounted on the vertical milling slide included a T-slotted milling table, indexing head and milling vice.
Schaublin grinding spindles
SV102 ball bearing grinding attachment
Schaublin have produced a number of different types of grinding spindle for the SV70 and 102 lathes, some employing plain bearings others with ball bearings. Early grinding spindles for the SV70 employ B6 collets while B8 collets are used in both the later SV70 and SV102 devices. Plain bearing devices have a top speed of around 10,000 rpm while spindles with ball races have a top speed of around 15,000 rpm.
SV102 internal grinding attachment
An internal grinding device was also available for both the 70 and 102 with a rather low maximum spindle speed of 18000 rpm.
SV102 grinding attachment mounted on milling attachment vertical slide
Schaublin 70 and 102 Grinding Carriages
The Schaublin 70 and 102 lathes can be quickly turned into cylindrical grinding machines through the use of the grinding carriage and grinding spindle. These carriages have covered slideways to prevent ingress of grinding dust. Of course, great care must be taken to prevent grinding medium contaminating bearings and wearing the tailstock and bed etc.
SV70 with set up with grinding carriage, plain bearing grinding spindle and overhead drive
Schaublin Overhead Drive for Milling and Grinding Attachments
The drive for the milling and grinding attachments for the Schaublin 70 and 102 lathes is provided by a 6mm round belt supported by an array of four pulleys and driven either by a separate motor as in the illustration below, or by the headstock drive unit on bench mounted open headstock machines as shown to the left. More recently Schaublin have adopted a column mounted motor with frequency control. Schaublin also offer the option of milling and grinding spindles featuring their own integral motor units.
SV102 worm and wheel dividing attachment
Headstock dividing attachments for the Schaublin 70 and 102 lathes are very rarely found on the second hand market. While these attachments are very useful they are easily substituted by direct indexing with a suitable dividing plate and detent. Indeed for many horological applications the dividing attachment is not suitable since some common horological wheel counts are unobtainable with a 1:60 ratio. After reading the instructions, I fell into a stupor because the drug had so many contraindications. Valium is sold only on prescription; however, the pharmacist didn’t even ask me for the doctor’s prescription, until I reminded her myself. The action turned out to be much milder than I read on the forum: I started to feel much calmer;I finally started to get enough sleep and stopped to get nervous over trifles.
Quick Change Tool-Posts
Schaublin list two types of quick change tool-posts for the 70 and 102 lathes, the (now French made) Multifix (left) and Tripan (right). Both types are excellent, the Multifix being particularly sophisticated with 40 indexing positions for the tool. However, in my opinion Tripan tool-posts are ideally suited to the 70 and 102 and being slimmer than the rather bulky Multifix unit, obscure the working area much less.
Schaublin list Isoma microscopes for fitting to the tailstock (left) and for use in the vertical slide of the milling attachment (below – also showing quill holder and quill). These are extremely useful for the setting up and measurement of work.
A number of screw-cutting and power feed attachments have been made for the Schaublin 70 and 102. However, like many of the specialist accessories for the 70, the screw-cutting attachment (left) was supplied in very small numbers and was eventually deleted from the accessory range in the mid 1960s. It is probably the rarest Schaublin 70 accessory on the second-hand market.
For the 102, Schaublin provided three seperate means of generating threads. The first type (right) consists of a train of gears driving directly from the headstock spindle through a telescopic shaft with a pair of universal shafts to the carriage top-slide feed-screw. The carriage top-slide feedscrew is supported by a hardened plug with a spigot which locates in the end of the feedscrew. When screw-cutting this plug is removed and replaced by the driving end of the universal shaft. No clutch in the screw-cutting drive chain is provided. The use of these attachments under power on machines without a back-geared headstock and not provided with a clutch and brake to the spindle drive must require nerves of steel!
The second method (left and right) which Schaublin referred to as “screwcutting attachment with leaders and gears” but also commonly known as “hob and drag” screwcutting, used a master screw, or hob, with a follower drawing a bar with a slide and thread form tool form tool. This method of screwcutting was more suited to batch production rather than one-offs. Schaublin also produced an hob-and-drag attachment specifically designed for the F-type production headstocks.
The third method of generating threads involved a special sliding spindle headstock – a one of the earliest methods of generating a thread on a lathe – in which the thread was generated by the tool remaining stationary while the spindle moved along the axis of the lathe. In this method the movement of the spindle is controlled by a master hob on the end of the spindle into which is engaged a follower which is fixed to the headstock. This screwcutting method is particularly suited to the production of short threads fine threads such as those used in optical equipment.
In addition to the geared carriage screwcutting attachment, for a very short time Schaublin also produced a very sophisticated belt driven power feed attachment. Featuring a multi-plate clutch and reversing gearbox, the powerfeed was transmitted to the top-slide feedscrew via a universal shaft with quick decoupling device. A further attachment allowed the drive to be taken to the cross slide feedscrew allowing powered facing operations to be carried out. To my knowledge, these attachments only appear in the 1957 catalogue – very rare indeed.
Spherical turning carriage
Schaublin spherical turning carriages are primarily designed to be worm and wheel controlled and operate by rotating a movable slide around a fixed central point. The attachment could produce both convex and concave work. Careful setting-up is required to ensure that the pivot point is on the lathe axis and at the correct position relative to the work. To this end Schaublin provided special setting devices. The carriage could also be converted to lever operation with the worm-wheel being used to operate a cylindrical rack acting as a stop.
Tool-room machines (TO designation) where usually supplied with a screw-operated tailstock. However, the standardisation of headstock height on all machines meant that tailstocks were interchangeable with a very high degree of accuracy long after initial purchase. Schaublin offered a range of tailstocks including lever operated (left), lever and spring operated (for grinding operations) (below) and, for the 102, turret-wheel rack and pinion operated (right). The turret wheel operated tailstock was mainly intended for second-operation work.
Lever and turret wheel tailstocks took W type collets, while screw operated and lever and spring operated had a tapered socket (SV70: 2º; SV102: 2MT). In general use the standard screw operated tailstock is more than sensitive enough for the smallest of drilling operations, however there are occasions when a lever tailstock provides that extra degree of sensitivity or fast operation. Schaublin also listed a B8 colleted revolving spindle to fit the lever tailstock. Driven from the overhead drive it could be run at up to 5000 rpm.
Schaublin 70 fitted with lever tailstock with B8 spindle
The T90 (T standing for “tour” – French for lathe) was imported into the UK in fairly large numbers and like the Schaublin 70 and 102 (which took a much greater share of the market) were most common in the turret lathe form. Mikron offered lathes for a wide variety of applications especially those associated with the horological industry. Lathes were specifically set-up for cutter relieving, optical work, semi-automatic turning etc. Mikron’s pivot-polishing lathe will be of particular interest to horologists.
Mikron pivot burnishing and polishing lathe
With Mikron’s output mostly geared toward production machines, toolmakers lathes are consequently fairly rare and because of their age are very often rather tired. The T90 lathe was complemented by a superb small milling machine the F75 (F standing for “fraiseuse” – French for milling machine). Originally machines were not painted but finished in bare cast iron for the early machines or what appears to be a metal sprayed finish on post-war machines.
Mikron headstock for 40mm collets
The Mikron T90 lathe had, as the name implied, had a centre height of 90mm and admitted 400mm between centres. Headstocks had hardened and ground spindles with cylindrical journals running in adjustable plain bronze bearings with ball-race thrust. Most spindles were bored to accept Mikron’s own W20 collet (see below), but other headstocks were available including a version intended for optical work accepting colossal 40mm shank collets. Of particular note on both the lathe and horizontal milling machine was the exquisitely made epicyclic back gearing which was incorporated into the headstock pulley.
Both the tool-maker’s lathe and the mill employed the same 20mm collet which appears to be identical to the standard Schaublin W20 (W20-4) collet, however it is slightly longer and employs either a 1.25mm or 2mm pitch pitch thread. These collets were only used on Mikron machines and are virtually unobtainable on the second hand market, and new are very expensive (£60+) and only available in a limited number of bores. However, the standard W20-4 collet can be employed with a new or modified draw tube.
A number of different tool-room carriages were produced for the T90. The most common screw-operated carriage has open ways for the top-slide with both axes having travels of 90mm, but Mikron also made a heavier duty version of known as the “reinforced slide rest” which had a solid rather than T-slotted top-slide and coarser pitch feedscrews. Perhaps the most desirable tool-room carriage had completely covered ways at the expense of longitudinal travel at 75mm rather than 90mm. Early carriages had rather small micrometer dials while later versions had large clear settable dials.
Mikron tailstocks were produced in a variety of forms, the most useful of which is the screw operated version. Like Schaublin, Mikron employed their own special taper in the tailstock barrel. Revolving centres are still made by Gepy for these machines.
Mikron T90 spherical turning attachment
Mikron T90 milling attachment
A wide range of accessories to meet the needs of both the horological tool-maker and for mass production of small components were produced. Of particular interest to the horologist and model engineer is the beautifully made milling attachment and indexing attachment. Both very rare on the used market, the indexing head uses Mikron W20 collets, but the milling attachment employed the very unusual W9 collet.
Trading for nearly two decades, Anglo-Swiss Tools draws on over thirty years experience in horology, precision engineering and the use and refurbishment of Swiss machine tools. Specialising in new and used Swiss-made manual machines and accessories, Anglo-Swiss Tools was established to meet the needs of the discerning horologist and precision engineer demanding the highest quality equipment in pursuit of excellence whether in business or leisure.
Precision manual machine tools and accessories for horologists, instrument makers and model engineers