|Last updated June 25th. 2011||Jewelling & JewellingTools|
Jewelling is very important for accurate work of watches. It is the
jewels that are the bearings in watches providing great reduction of
Traditionally jewels were mounted in watches set in specially made brass or gold settings, in which they were fastened and secured applying technique known as burnishing or rubbing in.
In modern production of watches a different method is used giving a faster and safer way to mount a jewel, the friction method. To mount a friction jewel it is necessary for a jewel to be larger in diameter a tiny amount and is pushed into the hole using a specially designed press.
|Here is a drawing which shows two types of jewels set in either the mainplate or a bridge of a watch.|
|There were many tools devised for preparing seat for jewels. There were specially profiled drill bits, capable of shaping the hole predrilled in plate or bridge, similar to the set shown on the image to the right and the one below.|
|This image shows one of the drill bits close up.|
The tool shown on this image was designed as adjustable and can shape
holes for any jewel diameter within its working range. Of course
the tool was used when making watches or new parts for them.
This type of tool was used with a bow as the motive power.
|Here is a close up of the tip of the tool.|
replace damaged jewel one needs to remove the old damaged one from the
setting without damaging it.
This job is usually done in a staking set using specialised stake with attachments designed for this purpose.
replacing jewels set in plate or bridge of a watch then different
tooling must be used.
To the right is shown boxed set of specialised tools, used to open jewel setting rim.
|To the right is another boxed set of specialised tools, used to close jewel setting rim.|
removing damaged jewel from the setting, done carefully to open it
without damage while pushing out old jewel.
It is necessary to use one of the tools shown to the right to clean the seat and open the setting as much as it is needed to allow insertion of the replacement jewel.
the replacement jewel set in its place one then needs to close the
setting again and thus secure jewel.
That is accomplished using one of the tools shown on the right. Slowly burnishing the setting's rim, adjusting the tool opening with the setting screw on the side of the tool, as the rim closes over the jewel edge.
make a new jewel setting one uses watchmaker's lathe.
Most of the work is done while setting is being held in the chuck without removal from it. One thus achieves greatest accuracy and concentricity of the work.
close the setting and secure the jewel in it, it is burnished
using any of the various small burnishers.
Here are several burnishers made by myself.
Suitably sized one is held in the collet type screwdriver (or pin vice) and the ball shaped end is applied to the metal surface which is then slowly moved over the edge of jewel much like it is done in lathe spinning.
final stage the setting is cut off and removed from the collet. To
finish the work and adjust the height of the setting, it must be
placed back into the collet.
For this purpose there are few types of specialised collets like the set of sub collets shown to the right.
|Another, smaller boxed set of jewelling sub chucks, this one containing eight chucks.|
|Image to the right shows construction of the sub chucks.|
|The close up of the jaws of the sub chuck holding the almost finished setting, ready for a final touch with the graver needed to reduce its height.|
the friction jewelling there are few tool sets available. I am using
the Seitz jewelling tool.
The main tool is the small hand operated press which is equipped with a reamer holding arbour, a press plunger for holding any of several dozen of attachments which are supplied with the tool.
|This is a pedestal holding large part of accessories, containing mainly various pushers, and reamers used for opening holes to the exact size needed for fitting of friction jewels. Also there are several anvils used to provide safe support for watch mainplate and/or bridges.|
|This is arbour for holding cutting reamers, whose shanks are tapered in order to provide accurate and sure mounting for reaming holes to size.|
|A close up of the arbour nose and couple of reamers.|
|This is press, with handle removed to allow reaming.|
|This is special accessory used to hold very small parts such as bridges when either reaming or friction fitting jewels.|
|The same accessory shown holding a rather small pallet bridge of a lady's wrist watch.|
|Here are some brass pushers used for mounting watch hands.|
|Here is a set of specialised pushers and anvils intended for fitting Incabloc shock resistant balance wheel jewel settings.|
we have a specialised set of pusher and anvil for safe lanterning the canon pinion.
The use of the micrometric adjustment of the press does come to the full advantage, as one cannot deform or squash canon pinion when lanterning.
see here the micrometer screw which is used for setting the limit to
which the press plunger will travel.
The scale is graduated in the 1/100 mm units, thus making press quite suitable for easy adjustment of the end shake of wheels in watches.
doing the end shake adjustment the plunger top needs to be
replaced with an adapter which then fastens the arbour securely to the
the adapter fitted onto the plunger, its motion is now governed not by
a lever, but exclusively with the micrometer screw.
Utilising micrometer screw graduated in 1/100 mm it is now possible to use press for the easy and accurate end shake adjustment or for precise height measurements inside of the watch movement or of its parts.
Jewel Hole Plug Gauges for checking size of jewel holes, calibrated to very tight tolerance. The test is simple go/no go.
Allows testing the size of a jewel hole from the balance staff through to wheel train.
Plug gauges range in size from 0.07 to 0.50 mm (0.003" to 0.020"), the step size is 0.01 mm (0.0004")
Also available in step size of 0.002 mm (0.00008")
Jewelled Pivot Gauge for checking the pivot size and roundness, sized from balance staff pivots to wheel train pivots.
The use is simple, pivot is fit tested to the jewels until one is reached that will accommodate it. The Jewel that fits the pivot being the correct size, just like with conventional ring gauges.
Jewel holes are in the range from 0.07 to 0.50 mm (0.003" to 0.020"), the step size is 0.01 mm (0.0004").
Also available in step size of 0.005 mm (0.0002")
|Jewelled Pivot Gauge similar to the above but with the extended range of jewel sizes, 0.07-0.20 mm in steps of 0.01 mm and 0.22-0.78 mm in steps of 2/100 mm|
A Set of High Precision Jewelled Pivot Gauges for checking the pivot size and roundness, sized from balance staff pivots to wheel train pivots.
Jewel holes are in the range from 0.07 to 0.50 mm (0.003" to 0.020"), the step size is 0.0025 mm (~0.0001").
forget roller jewels.
To replace one, one needs either a very steady and sure hand with a pair of tweezers or a roller jewel holding tool.
Much like the vintage K&D roller jewel holding tool shown on the right which provides one with a safer means of holding roller jewel for placing it in the roller.
|Or perhaps a newer design holder, currently supplied by Bergeon, comes in two sizes to fit two size ranges of roller jewels.|
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