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Benson Lathes & Shapers
Benson Shaper   Benson Benli Lathe  Benson Milling Machine

A Benson catalogue is available

William Benson established his company in 1855 at first describing himself as an "Engineer, Millwright and Tool Makers". The firm, based in the St. Ann's area of Nottingham in the Robin Hood Works, Robin Hood Street, was engaged originally in the manufacture of machines for use in the extensive and important Nottingham lace trade and only later branched out to include such diverse products as steam engines, pumps, boiler fittings, hand and power presses, swaging machines, malt crushers, chuck jaws, lathe slide rests, a tiny hand-operated shaper, a similarly tiny bench horizontal milling machine and a line of surface plates, straight edges and other inspection and precision measuring equipment. One of their advertisements boasted: "Patentees, designers and builders of the most improved machinery for cutting Jacquard loom cards" - the revolutionary and ingenious Jacquard being worthy of close study by anyone fascinated by in ingenious machinery. Like many similar organisations of the time the firm also had the facility to design and manufacture special-purpose tools - their boast being that they could: "design and make any high-grade single-purpose machines for any operation." In the years leading up to WW2 in 1939, they became known in the machine-tool trade for their small, high-precision lathes, the company using, in their catalogues, the contemporary American nomenclature Bench Lathe for a small, non-screwcutting, high-class machine intended for use on the bench of a skilled craftsman. However, not all their lathes were so small, and limited numbers of larger more conventional backgeared and screwcutting machines were made,  probably up to 6-inches in centre height. Benson lathes enjoyed a formidable reputation and were favoured by users engaged in critical work including, amongst many others, the Royal Air Force, numerous Admiralty Experimental Stations (dotted around the country), The Government Gauge Factory, Sperry Gyroscopes, Cambridge Scientific Instruments Ltd., the Royal Aircraft Establishment at Farnborough and the Navy - there is one on H.M.S. Belfast moored in the Thames.
Oddly, the Company used a set of rather confusingly similar code names for their lathes including: "Benla", Benle", "Benli", "Benlow", "Benly" and "Benlo". Fully-specified and beautifully constructed, the Company's main product was the Benli, a lathe built in early and late types and always fitted with taper turning (9-inch and 25-degree capacity) as standard; backgear, however, was listed as an option and, when fitted, allowed spindle speeds to span 70 to 840 rpm. The headstock carried a hardened and ground spindle whose nose threads ground were finished in situ after assembly to ensure absolute concentricity. The spindle bearings were of traditional "precision bench lathe" type - as first developed by Stark in the U.S.A. during the 1800s - in hardened and ground cast steel and formed as a double cone (shallow for support and steep to absorb thrust) at the front and a tapered bronze at the rear. Although the 3-step cone pulley was set with its largest diameter to the left the purpose of this arrangement - to allow a greater mass of supporting metal to surround the front bearing - was, unfortunately, not taken advantage of by the makers, the cut-out beneath the bearings being purely rectangular in shape and the casting the same width from end to end. It is believed that later lathes had this deficiency corrected by the addition of a large fillet in the casting arranged so as to give better support to the bearing housings.
As befitted a genuine precision lathe, the bed of the Benli was enormously wide and deep in comparison to the centre height and carried an unusual combination of ways: flat-topped with narrow 90-degree sides for the saddle and a sunken, central V for the tailstock. Located against front and back 60 ways, the the saddle was gibbed to the bed by a tapered wedge, the  adjustment being by a screwed rod and locknuts
To preserve its accuracy the leadscrew (clasped by double nuts) was used only for screwcutting, the power sliding and surfacing feeds being provided by a separate powershaft with selection by a quadrant arm (located by a spring indent) and engagement by a flick-up-and-down lever on the front of the apron. On early models the power shaft could be driven from either the screwcutting changewheels or, at a much finer rate of feed, by an auxiliary flat-belt, the drive pulley being (rather ingeniously) mounted not on the headstock spindle but on a shaft geared down from it. On later machines the fine feed was arranged differently to give, presumably -  though it has not been possible to confirm this - an even slower rate This system (besides connecting as usual to the screwcutting changewheels) had a gear on the end of the headstock spindle driving a rear-mounted layshaft that took a drive, via sprockets and chain, to a separate train of gears feeding into a 4-speed gearbox from which emerged the front-mounted power shaft.
On early models power cross feed was not fitted and, because the drive to the power-shaft gearbox did not pass through the headstock-mounted tumble reverse, the apron had to be fitted with a feed reversing mechanism that used bronze bevel gears. Selection was by a quadrant lever and engagement through a flick-up-and-down bronze "finger-hook" lever positioned in the bottom left-hand corner of the apron's front face. This mechanism, also used on many other lathes including the Harrison L5, ensured that, no matter how heavy the cutting load, the disengagement was instantaneous.  A long cover, extending from the left-hand face of the apron, gave protection to the 1-inch diameter precision-cut leadscrew.
Top and cross slides were hand-fitted, individually scraped to a perfect fit and driven by square-section threads running through bronze nuts. The top slide was mounted on a large, very stable round boss and the micrometer dials, even on the models from the 1920s, were of an unusually generous size for the time.
Inexplicably, but as on so many precision bench lathes, the tailstock barrel carried an inadequate a No. 1 Morse taper and the barrel locked by that most crude of methods, a long slot cut along the casting and closed down by a pinch bolt - an arrangement possibly copied from Schaublin practice.
Although in post WW2 years only the larger 3
3/4-inch centre-height (actually 313/16") backgeared and screwcutting "Benli" was built (together with a basic version) originally others sizes  were offered: the "Benla", a 33/4-inch centre height plain-turning model (with detachable screwcutting as an option, when it became the "Benle" ) and the "Benly" a 21/2-inch x 22" screwcutting lathe. A useful range of beautifully-finished accessories was also listed.
Benson Serial Numbers allow some insight into production numbers - one marked 598/45 for example would almost certainly have been made in 1945 and have been the 497th example made -  assuming numbers had started at 101, as they often did.  Sadly, production of these fine machines stopped during the mid 1940s - and they are now rare and sought after with experienced turners all agreeing that the quality of their construction is outstanding.
The Benson works closed in 1963, the St. Ann's area being, by then, a sadly run-down and semi-derelict area ripe for residential development. All traces of the original factory have disappeared and even the original road layout has vanished under a new arrangement of streets and housing estates.
If any reader has a Benson machine tool, the writer would be pleased to hear from you.

Later model Benson 3.75 x 20" "Benli" (or "Benlow") with a feeds' gearbox, dog clutched drive to the power shaft and power sliding and surfacing feeds - note the enormous depth of the bed

Elegant lines of the Benson Headstock. Note the beautifully constructed cast-aluminium backgear covers.

Section through a Benson headstock of the 1920s

Changewheel drive to the leadscrew and chain drive to the gear train driving a 4-speed feeds' gearbox. Some models have been found with a rather under-engineered flat belt drive in place of the chain - so perhaps the latter is an owner's modification.

4-speed feed gearbox

A view showing the unusual combination of ways: flat-topped with narrow 90-degree sides for the saddle and a sunken V for the tailstock.

Benson "Benla" and "Benie" lathes
Although the Benson plain-turning precision lathes were loosely based on the screwcutting model, the conversion was properly engineered and included a simpler bed with a cross section more suited to accurately holding a bolt-down compound slide rest. Note the use of 4 screws to hold the cross-slide end plate, a method also used by some American precision bench lathe makers including Pratt & Whitney.
A screwcutting version, illustrated below, kept the bevelled-edged bed and through-bolt fastening for the compound slide. The compound slide-rest clamping bolt must have been slackened to permit a sliding feed to the carriage, but just how this setting was made and maintained. is not clear. The spindle and its cast-steel bearings, like those on all the company's other lathes, were hardened and ground with the spindle thread finished in situ after assembly to ensure absolute concentricity.

Benson "Benla" and "Benie" lathe with screwcutting attachment

Benson "Benly"  2.5" lathe
First produced in the early 1920s this delightful machine was Benson's smallest lathe, with a centre height of 2 1/2" and a capacity between centres of 1". It was available in either plain-turning or screwcutting versions, the maker's code name for latter specification being "Benly" - but unknown for the former.
Both made from hardened and ground steel, the headstock spindle and front bearing were formed as a double cone while the left-hand end bearing was a split-cone, phosphor bronze bush, adjustable for wear. The headstock spindle nose was hardened and ground and threaded for chucks and backplates; a draw-in collet tube was fitted as standard and supplied with a combined collet and centre; collets were available in 1/64" increments to a maximum capacity of 3/8". The spindle, fitted with a 4-step pulley (with diameters of: 4
3/8", 37/8", 33/8" and 27/8" diameter) was designed to accept 5/16" round leather belt whilst the drive countershaft, with its swivelling bearings and fast and loose pulleys, could be mounted on the bench, wall or ceiling.
In order to obtain a slow carriage feed (and cut the fine threads suitable for instrument work) a 20 t.p.i. acme-form leadscrew was fitted. However, it is not evident from the illustration quite how the screwcutting was arranged for, not only was there no tumble reverse, there appears to have been no dog clutch on the leadscrew and, with the saddle nut of the "full" type, it is not clear how the drive could be disengaged.
The cross slide with its travel of 3
1/4", was propelled by a square-section thread running through a bronze bush with both top and cross slides fitted with, for the time, with decently-sized micrometer dials engraved at intervals of 0.001".
Guided by a central V-way, just as on the company's larger lathes, the tailstock was, unfortunately, fitted with a tiny No. 0 Morse taper, a fitting that would have caused the operator endless frustration.

Above: Benly half tailstock for quickly interchangeable spindles - a popular type on early precision lathes.



Left: large "bell chuck"

A 1924 Benson  3.75" x 16" between-centres "BENLO" - the top-of-the-range model - fitted with taper turning and on the maker's stand. The countershaft probably mounted three sets of fast-and-loose pulleys to provide a means of switching instantly from high to low speed range - or into reverse.

The larger backgeared and screwcutting Benson, coded as the "Latre", and as sold to "Foreign Railway and Cable Companies". The assembly could be supplied with either motor or treadle drive or, as illustrated, with both. The cast-iron legs (the contemporary term was "standards") were joined by a polished oak top with a single drawer provided to store collets, tools and work in progress. The overhead drive (also carried on "standards") allowed high-speed grinding and milling attachments to be mounted in the toolpost and so considerable extend the lathe's versatility - a set-up that would have been useful in a remote location equipped with a limited range of machine tools, or as machine for use in a portable workshop.

An assembly designed to allow instant start, stop and reverse of the spindle to be made by foot-pedals operating through wires linked to three fast-and-loose pulleys sets.

A partial list of Benson users - with many engaged in precision work of the highest quality

A beautiful little Dividing Head with a plate having three circles of  84, 60 and 48 holes and a 120T worm wheel. The spindle accepted the same collets as the headstock.

Simple indexing attachment for mounting on the Swivelling Vertical Slide

Swivelling Vertical Milling Slide to accept milling/grinding units and indexing/dividing heads.

Swivelling Vertical Slide with T slots

Vertical Slide with high-speed Milling and Grinding Unit.

E-Mail Tony@lathes.co.uk 
Home    Machine Tool Archive    Machine Tools For Sale & Wanted
Machine Tool Manuals  Catalogues   Belts   Books  Accessories

Benson Lathes & Shapers
Benson Shaper   Benson Benli Lathe  Benson Milling Machine

A Benson catalogue is available