Last update Apr. 25th. 2014

Special Tools and Accessories
Carl Zeiss - Stereo Microscope Projector 
Plastival 50
Stereo microscope projector is used to enlarge images of small components and then project them on a precision ground frosted glass and thus enable their inspection. Carl Zeiss Plastival 50
Microscope projector showing a watch wheel magnified 32 times, lighted from above and from below.

This Stereo Microscope Projector is capable of 8x, 12.5x, 20x, 32x and 50x magnification, projecting images onto a frosted screen 160 mm in diameter and 120 mm high. 
Carl Zeiss Plastival 50
Damaged Grana fourth wheel, with one tooth broken, is  shown next to the watch gauge showing its real size. Enlarged image of the wheel
The same wheel, magnified 32x and projected onto the frosted screen of the microscope projector.

Image is used to compare the tooth geometry to the milling cutter during its making. This cutter will be used in machining a new wheel, with teeth exactly matching the old one in order to replace it. 
Enlarged image of the wheel
 The Measuring Microscope
This Srb a Štys measuring microscope came into my possession as part of the lot of surplus equipment discarded from one of the forensics laboratories.


Microscope is made of solid brass, it magnifies 24X and has a cross hair in the eyepiece, used to determine starting and ending points while measuring length using  high precision micrometer, X-axis travel 0 to 25 mm, with 1 µm precision.
Typical view, of the non inverted image, as seen through the eyepiece  of Srb a Štys measuring microscope, with 6 mm field of view.

The image shows a balance staff, 337/100 mm long, enlarged 24X, the elements of which are being measured along the X-axis.

Second image shows 'scope used to measure the size of the pallet stone without removing it from fork. 

Using a simple  protractor, one can measure the impulse face angle off the computer screen.

Micrometer thumbwheel has graduated divisions of 1/100mm with vernier scale allowing readings down to 1/1000 mm i.e. 1 μm. 

Crosshair is used to visually set the start and the end of the measurement of the very small part, rather than using two surfaces touching each other, which may introduce errors. 

Thus, using the optics, we allow margin of error to stay within limit of ±0.5 μm, by eliminating number of sources of error. 

The base cross bar can be removed for mounting a cross slide or some other accessory for easier and more precise manipulation of the object being measured. 
In order to use the 'scope as was originally intended, not having any of the original accessories, I have mounted a spare cross slide, part of one of the Boley & Leinen watchmaker's lathes, onto the microscope cross bar.


 The Spot Welder
Another special tool used in watchmaking workshop is  the Spot Welder. 

Its intended use is for the  preparation of the watch mainspring ends.

Often the mainspring has the wrong end-piece, instead of one type it has another while the correct one cannot be procured.

Thus the repairer is forced to make do with what is available and is in stock.
Enlarged image of the wheel
In such situations a spot welder is indispensable, and as it happens spot welder of the orthodontic variety is just right.

Being capable of spot welds as well as of silver soldering if using carbon electrode as the upper one. 

This unit is capable of delivering 2000 Amps of current in either a short burst selected by setting the potentiometer, or longer periods selecting brazing mode and using carbon electrode.
Enlarged image of the wheel
In practical terms this means that this unit can spot weld two sheet metal pieces or wire as thin as 0.05 mm (0.002") to as thick as 4.00 mm (0.160")

One great design treat is the ability to swivel the welding electrode heads and thus choose and quickly change needed electrode out of the four possible, the mounted ones. 

Enlarged image of the wheel
Spot welder in action, actually joining bridle to a white alloy mainspring, spot welding the two parts together.

There is yet another use of this spot welder. 

One can also use hand held electrodes to join pieces of the complex forms which cannot be easily presented to the electrode posts of the welder itself.
Enlarged image of the wheel
 Tool and cutter Grinder
Alexander 2CG, single lip tool and cutter grinder, is intended for grinding tungsten carbide, as well as HSS tools, designed not for industrial production but for small workshop requiring high precision tool bits of various forms.

Using diamond wheel dressing tool with built in micrometer, wheel dressing is easily accomplished even with the cutter in place. The 2CG grinds offset radii, back relief, dovetail cutters. Fast, accurate means to produce or regrind single lip mold & engraving cutters.

Adjustable work head (0.001" increments) moves parallel to the grinding wheel axis, with free or controlled movement across the face of the grinding wheel. Universal movement allowing the work head to rotate horizontally or vertically. Third cross-slide with vernier scale graduated in 0.001" for grinding offset radii 90° rotary movement that can be increased additional 30° when grinding back relief or dovetail cutters.

The grinder makes it possible to produce various cutting tools in tungsten carbide which are often used in a watchmaking workshop.
The  Alexander 2CG Single Lip Tool and Cutter Grinder

Bench top version, built quite rigidly to withstand years of use, weighs about 40 kg (~ 85 lb).

Apart from some cosmetic blemishes, result of careless use by the previous owner, T&C grinder is in a perfect working condition, with practically no wear.  
A view of the indexing head showing all possible rotation and movements of the head. 
Another view of the indexing head showing it from side.
Feed screw adjustment knob, one full turn is equal to 0.050", graduated in 0.001" divisions, .
The set of 18 pcs. 355E (L20) collets which have come with the grinder. 

Collet sizes range from 1 to 20 mm in 0.50 mm steps.

These collets can also be purchased with square and hexagonal openings, both in Imperial and Metric sizes.
An image showing the size  of the 355E collet compared to the Schaublin B8 collet (8 mm/ WW collet). 
Diamond tipped tool for wheel dressing.
The Twist Drill Grinding attachment allows grinding drill bits from 3.0 to 18 mm while maintaining proper angles.
Mounting flanges necessary to achieve fast and accurate and highly repeatable change of the grinding wheels as required for grinding many different metals and alloys.

These had to be made as the Alexander 2CG is not in the production any more and if found as NOS the price is exorbitant.
A diamond wheel cup designated 12A2-45 used to grind tungsten carbide.

Of course, one needs at least several grit sizes as may be required to achieve desired low roughness of ground surface. 

These wheels are designed for dry grinding so diamond particles are resin bonded. 
For HSS tools one needs different abrasive material like aluminium oxide. 
Yet another cup of different grade of aluminium oxide.
An example of tungsten carbide spade drill bit, 0.60 mm in diameter, ground with Alexander 2CG.

Using the Alexander grinder I have been able to grind tungsten carbide spade drill bits as small as 0.30 mm in diameter. 
Another example, this time a HSS lathe boring tool, ground from 6.0 mm (~0.25") square stock.
The same tool viewed from another angle showing the relief angles which are easy to control using the Alexander 2CG.




Copyright © 2004, 2011, 2014, 2015, 2016 by Dushan Grujich. All rights reserved.


 Copyright Notice








 good hits
Websites Statistics Tool