Is it a fact that more than 17 jewels in a vintage OR modern watch is some kind of SALES PLOY??? ...
Though "17 jewels" is your typical mark of quality, additional jewel bearings often means better precision.
Most "fully jeweled" time-only watches have two cap jewels, two pivot jewels, an impulse jewel for the balance wheel, two pivot jewels, two pallet jewels for the pallet fork, and two pivot jewels each for the escape, fourth, third and center wheels
But if it is an AUTOMATIC movement or a CHRONOGRAPH, MULTI-FUNCTION OR OTHER COMPLICATED MOVEMENT, there is a requirement for additional bearing material.
Thus, MOST watch movements with more than 17 jewels indicate higher precision ... and more time and MONEY placed in assembling the movement.
The crystalline nature of sapphire lends itself to very fine polishing.
The sapphire surface has excellent oil and lubricant-retention ability.
These factorsmean that the finely polished sapphire bearing has a natural low-friction characteristic.
Now, there are some watches that utilized and advertised 21 to 100- jewels in an attempt to portray their watch as being a higher quality jeweled bearings ... but the funny thing is, many of these turned out to last longer and run better than higher priced movements with 17 or less jewels
I, for one, would rather have Jewel bearings at all and any point of movement, friction or pressure, because the low and predictable friction only improves watch accuracy, lessons wear and holds lubriucant better than metal bearings.
Quaility bearings used in top-of-the-line timekeeping devices, gyros, and instruments are usually made of synthetic corundum -- commonly known as ruby or sapphire.
The extensive use of such bearings in the design of precision devices is mainly due to the outstanding qualities of the material.
Sapphire's extreme hardness imparts to the bearing excellent wear resistance, as well as the ability to withstand heavy loads without deformation of shape or structure.
so, when viewing the watch you must take into consideration the brand, name, country of origin... and , the amount of jewels...
to leave you with an excellent example.. the BOLUVA 21 JEWEL AUTOMATIC of the 50s/60s are excellent time pieces that have proven their jeweled reliability thyrough the abundance of thos that survived and continue to keep excellent, accurate time after 50 years even though many of these were never, ever serviced!
how to keep your time