email: tony@lathes.co.uk
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Cowells Vertical Miller
Cowells Miller Page 2   Cowells Home Page   

A book to help with this milling machine is available

Of a simple but efficient design, the Cowells vertical miller has been in production for many years and proved to be an accurate and reliable - if rather expensive machine. However, as this type of machine is rare, demand for second-hand examples always exceeds supply and consequently, if kept in pristine condition, do represent an excellent investment. Alternative miniature milling machines include the vastly more pricey Aciera F1 and Sixis 101, the lovely little Stevens, the German Nora, American Servo and Precise and the original Wolf Jahn and its decedents the Leinen BFL, Ultra, Excel, Sigma and BCA.
Two versions have been manufactured: the first, which we shall call the Mk. 1 was well-finished, painted in silver and with the head casting having a rounded front face and a thin base foot in cast aluminium. The current version, the Mk. 2, fitted with the same table and knee, is otherwise distinctly different: painted a dark blue, its head is (to the writer's eye) a rather ugly, rectangular casting although the base, again in aluminium, was improved by being made thick enough to incorporate (and so safely enclose) the electrical controls - an on/off switch, run light and a wheel by which means the speed of the high-quality, Parvalux 1/6 h.p., continuously-rated DC motor can be varied from 40 to 4000 r.p.m.
Both the knee and 8" x 2" table on all versions are in cast iron while the hardened and ground spindle, running in a pair of high precision, 48 mm diameter, angular contact bearings, is driven positively by a toothed belt and fitted with a nose that takes the specially designed  Cowells' tooling. Protected by closely-fitted caps to seal out dirt, the bearings have their pre-load set by a  fine-threaded adjuster nut. 
A late edition of the maker's catalogue states:

An extremely accurate and robust Vertical Milling Machine of massive cast iron construction to absorb the vibration and stress of milling. Capable of machining tough material with accuracy, the Mill may also be used for co-ordinate drilling. The machine has a 4000 rpm electronic variable speed control and positive non-slip toothed pulleys and belt drive. Each machine is individually hand fitted by an experienced engineer to exacting tolerances. All electrics are safely housed in the cast aluminium base unit. The
V. Mill may be fixed down or used as a free standing unit if portability is required.
Headstock
The Headstock is of a massive iron casting and is aligned, fixed and dowelled in accurate alignment with the V. Mill table. 0.012 mm (0.0005") over a table length of 180 mm (7.0"). The headstock incorporates two 48 mm diameter, precision, angular contact bearings. The headstock spindle is hardened and ground and carries a fine threaded adjuster nut for bearing pre-load and the elimination of spindle end-float. High tolerance bearing caps are fitted for the protection of the bearings. The headstock spindle has been designed to accept Cowells tooling - collets, flycutters, drill chucks and arbors.
The headstock spindle has an internal engagement pin and tooling is secured in the precision ground mouth and bore of the spindle via a draw in bar supplied with the machine.
Slides
All slide ways (the table is 8" x 2") are dovetail in form and fitted with gib strips for the elimination of play and eventual wear. Clamping locks are also fitted so that each slide may be locked during the machining process thereby ensuring rigidity..
Column, Knee, Saddle and Table
All are machined from solid cast iron bar providing the mass, stability and rigidity so essential in any quality machine tool and of particular emphasis in milling work where interference cuts are common. The table has two Tee slots for the mounting of accessories such as Dividing Head (RGB61) and Machine Vice (RGB57)
Handwheels
The handwheels fitted to the table and cross slide are stainless steel. The large diameter handwheel fitted to the Vertical feedscrew is of a durable nylon with steel insert. All handwheels are fitted with very accurate computer laser etched, re-set to zero, calibration dials. The clearly marked dials are graduated in 50 increments of 0.02 mm.
Drive System
The British manufactured Parvalux electric motor has a 4000 rpm. capability and a continuously rated output. Variable speed drive is provided through an electronic speed control board. Toothed pulleys are fitted to both motor and headstock and the toothed drive belt ensures positive non-slip drive. A quick release fibreglass guard shrouds pulleys and belt.
Base Unit
The cast aluminium base unit houses the electronic speed control board and switchgear. The base is provided with four pre-drilled fixing lugs. The Vertical Mill can however be used as a free-standing unit should constant portability be required.
Cutting gear wheels and pinions between centres
Raising blocks for the (RGB61) Dividing Head and lathe tailstock are available for gear/clock wheel & pinion cutting. The Vertical Milling Machine can be supplied with an extra length table and knee so as to accommodate a pinion length of 75 mm between Dividing Head and Tailstock and a maximum wheel blank diameter of 110 mm..
Pictures continued on Page 2

Mk. 2 Cowells vertical miller with the angular head in blue. Both the knee and 8" x 2" table are in steel while the angular-contact bearing supported spindle is driven by a toothed belt from a thyristor-controlled, variable-speed motor.

A first generation Cowells vertical miller with the well-finished, round-faced head and thinner, silver-painted cast-aluminium base

Cowells Miller Page 2   Cowells Home Page   

A book to help with this milling machine is available

Cowells Vertical Miller
email: tony@lathes.co.uk
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