Description

Vintage Cooke Troughton & Simms M7000 Research Model Microscope with polarising functionality c1960s

Offered for sale is a very capable and well-equipped example of an M7000 binocular research-grade microscope by well-known British optical manufacturers Cooke Troughton & Simms (CTS) of York.  This example will date to around the 1960s and it bears serial number M701893.  It’s in pretty well original condition with additional sub-stage fittings added to enhance its polarising functions.  This therefore making a rather good polarising microscopy proposition, so probably one for the collector or serious amateur.  According to my CTS booklet it’s most likely to be the M7250R2 Universal Polarising Model (shown in final few listing photos) with binocular body and various other accessories as set out in the listing – probably quite a rare example with this type of comprehensive configuration.

The M7000 model series was first introduced by CTS in the late 1940s, with the final examples produced during the mid-1960s when the CTS brand name was dropped by owners Vickers Instruments.  The condition is generally very good for a working instrument, it’s got virtually no signs of wear and it has recently been through a sensitive clean, check-over and lubrication. 

Turning to the main technical details of this quality vintage binocular microscope, we have a U-shaped foot with twin uprights to pivot, with tension adjustment available via lever.  From the pivot point rises the limb in Lister-style arrangement with coarse and fine focus attached.  There’s a binocular eyepiece unit that’s adjustable for both focus by gently twisting the right-hand eyepiece tube and eyepiece separation by gently pulling on the adjustment tabs.  This binocular unit is fixed at +1.7x magnification therefore effectively giving the eyepieces a 70% magnification boost.  The binocular head is in good clean condition for its age and works pretty well.  

The eyepieces are as follows:

– 10x magnification widefield

The coarse focus system moves the main microscope optical tube in a vertical plane, with its controls at the top of the limb.  There is a lovely smooth action through the twin-sided thumb-wheels – travel and focus are both good with the tube holding position throughout its working range.  Fine focus adjustment essentially works by moving the nose-piece only, therefore the fine focus mechanism doesn’t carry the full weight of the main focus tube and monocular/binocular head and therefore has an almost frictionless action – a neat CTS patented design feature that works very well.  

With is being an M7000 series model set up specifically for polarised light microscopy, there’s a number of special features built into the optical tube – these are:

– polaroid analyser on in/out slider with replacement polaroid film – note analyser has 90 degree rotation
– wave-plate recess with dust cover
– centering via twin thumb-screws

There’s a useful mixture of progressive magnification objective lenses with a rotating 4-way turret which clicks into place positively as each objective is rotated into its viewing position.  The objective lenses are as follows:

– 5x magnification Achro – Beck
– 10x magnification – CTS
– 15x magnification Para by Watson
– 40x magnification – CTS

(The effective overall magnification available therefore ranges from 85x to 680x with the highest magnification objective)

This version of the CTS M7000 tilts for inclined viewing and holds in position well, it can be tightened further as required via the pivot locking mechanism.  The specimen stage is fully mechanical being a CTS circular design specific to polarised light microscopy, with the following special features:

– full 360 degree rotation which is well damped and can be locked in position if required
– external 360 degree scale
– centering via twin thumb-screws
– smooth x/y movement
– specimen clips that are adjustable for position and one arm is sprung – system works very well
– vernier scales for both x and y axes

The stage mechanisms all run nice and smoothly being perfect for holding and maneuvering slides/specimens of various sizes. 

Sub-stage there’s an Abbe-type condenser in a ring/dovetail mount with working iris and centering via twin thumb-screw adjusters.  The whole sub-stage has height adjustment via a rack and pinion system with single-sided thumb-wheel control.  The sub-stage is also fitted with additional polarising hardware as set out below:

– an unusual sub-stage goniometer giving 130 degree angle measurement with indicator arm as shown
– polariser with rotation and 360 degree external scale – smooth rotation
– additional condensing lens which also has a rotation feature
– note: 32mm filters can be added on top of the polariser as may be required

The polarising functionality works well with extinction when the polarisers are crossed.

Lighting is via a plano-concave mirror in a gimbal mount with very good silvering to both sides.

The overall condition of this M7000 series technical research-grade universal polarising microscope is really very good and it’s got the benefit of very little evidence of wear to the paint finish, with only the odd minor chip where one would normally expect to see some signs of use for a vintage piece of technical equipment.  

In summary, this is a really well-equipped vintage technical binocular polarising microscope from quality British optical firm CTS that makes an excellent microscopy set-up as it caters for polarising and petrographic applications.  It may therefore appeal to both specialist collectors of technical equipment and of course those seeking a comprehensively equipped good quality CTS M7000 model to add to their collection.  It’s also got an imposing retro look, which makes it a great display piece in its own right.  It’s fitted with a precision mechanical stage which is a must for high-magnification use and is essentially usable out of the box with a bit of time spent getting to know it and setting up its various features and controls for optimum viewing results.  It can of course also be used for normal brightfield microscopy, by setting the analyser to “out” and swinging the polariser out of the optical path.

This microscope equipment is both delicate and heavy overall weighs in at well over 6kg with packaging.  It will be partially dismantled, very well packaged for transport and will be shipped by insured courier upon receipt of cleared funds.  

Thanks for looking.