email: tony@lathes.co.uk
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"Trident" Lathe

Trident Lathe Page 2



Although badged as a "Trident" the manufacturer of this lathe is unknown. However, with the splash-lubricated spindle-speed gearbox and clutch mounted within the headstock-end cabinet leg, it would appear to be of a type common from the late 1920s until the early 1950s in continental Europe - and probably of German manufacture. One unusual aspect of the design was the economical use of the plinth walls as part of the gearbox structure - more usually this would have been a self-contained unit, mounted separately within the stand. Positioning the gearbox inside the leg allowed some degree of isolation from the transmission of gear noise to the workpiece - and also permitted the use of a wide, smooth-running flat belt as the final drive. The use of what appears to be an original twin-V-belt drive from motor to gearbox input pulley, together with the lathe's general appearance, would suggest a manufacturing date at some point between 1932 and the late 1940s.
A favourite trick of larger machine-tool distributors, and even some smaller dealers, was to hide the origins of a machine by having an easily-replaced door cast with a suitable name or logo. As no lathe manufacturer called "Trident" can be traced, it's safe to assume that this is exactly what happened to this machine - with the real manufacturer in Germany, Czechoslovakia, Austria or Hungry suitable disguised.
With inverted V and flat ways the gap-equipped bed was entirely conventional (though the 4-bolt gap piece was unusually long) and carried a saddle with T-slotted wings shorter to the left than the right. Heavily-constructed, and rather deep, the apron appears not to have held a supply of oil to lubricate the power sliding and surfacing mechanism. Feeds were selected by the usual front-mounted quadrant lever and engaged through a wind-in-and-out clutch - the latter unfortunately not allowing the drive to be flicked positively into and out of engagement. Unless the clutch was blessed with a particularly sweet action it might happen (as on similar lathes) that a heavy cut could cause the mechanism to "wind up" - and become almost impossible to stop. Screwcutting was by changewheels driving through a gearbox that gave 3 pitches and 3 sliding and surfacing feeds for each setting of the changewheels.
Neatly mounted on the back of the heavy cast-iron headstock-end plinth the electric motor was carried on two vertically adjustable rails held in horizontal T-slots - thus making it a simple task to adapt almost any make, of a suitable rating, to fit. Drive from the motor was by twin V-belts, through the plinth-mounted 3-speed gearbox and reversing clutch unit to emerge onto a single-step pulley with final drive to the 38mm bore headstock spindle by flat belt. The long control lever on the front face of the headstock-end plinth not only engaged and disengaged the drive but also acted to reverse the spindle - a most valuable addition to the lathes practicality. The headstock spindle ran in large bronze bearings, carried in adjustable taper housing, and with backgears of helical form--an indication that this was a machine of better-than-usual quality. Assuming the gearbox output pulley to be original, the designer's choice of a single step instead of multi-step headstock pulley is  interesting for, although it reduced the number of spindle speeds, it did allow the use of an unusually wide belt to help prevent slip at slower speeds.
It is not known if other machines tools were branded "Trident" - although the same lathe has been found badged as a "Jardine" for a Hong Kong import company - but, if you have one, the writer would be interested to know..

6.5" x 30" gap-bed, backgeared, screwcutting and power sliding and surfacing "Trident" lathe.

Although not fitted with a full screwcutting gearbox the Trident had a 3-speed box that provided 3 pitches and 3 rates of sliding and surfacing feed for each setting of the changewheels.

The headstock-end plinth doubled as the spindle-speed gearbox and reversing clutch unit. A favourite trick of the re-badging industry was to have an easily-replaced door cast with a suitable name or logo. As no lathe manufacturer called "Trident" can be traced it's safe to assume that this was a pseudonym adopted for one of the larger machine-tool dealers in the UK for their imported range.

The back of the heavy cast-iron headstock-end plinth was fitted with two horizontal T-slots designed to accept two vertical motor rails--thus making it a simple task to adapt almost any suitably-sized electric motor to fit. As the V-belt drive appears original this would put the lathe as post 1931, but almost certainly not later than 1950.


The original - rather perfunctory - cast-iron belt guard in place

Helical backgears - pointing to a machine of better-than-usual quality - with adjustable, draw-in bronze spindle bearings. Note the designer's choice of a 1-step pulley (that to the left is not used) reducing the number of spindle speeds but allowing the use of an unusu

A clear picture of the belt drive system. To provide some form of belt-tensioning device an owner has fitted a jockey wheel - though it would have been better placed at the back of the belt, causing it to wrap more closely around the drive pulley.

Inside the 3-speed spindle-speed change gearbox showing (foreground) the forward-reverse clutch mechanism


Trident Lathe Page 2

"Trident" Lathe
email: tony@lathes.co.uk
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