Ronda 9035-21

Description

Although Ronda was mainly famous for their pin lever movements of better quality, they produced also a number of true pallet lever movements, signed “RAX”.

The Ronda 9035-21 with its diameter of only 8 3/4 lignes (19.3mm) is a movement for ladies' watches. It debuted in the early 1970s and was used for roundabout ten years.

The base plate of the red-golden toned movement shows, that we have a Roskopf-like construction, and that is a very well executed movement, where all important bearings contain rubies.

The way, the rubies are set, is odd, since the rubies are pressed into square holes of the base plate.

The gear train is a mix between Roskopf and conventional lever movement, since it contains a directly driven center second.

The mainspring barrel drives the second wheel, followed by third wheel, center seconds wheel and finally the steel escape wheel.

The two leg anular balance, which beats already with 21600 A/h on the version with suffix “-21” is protected against shocks by two KIF Protechoc bearings.

It’s exact frequency can be adjusted on the hairspring key only.

As escapement, a swiss pallet lever escapement is used.

The double cannon pinion contains a slipping clutch. The lower part engages, like on Roskopf movement, with the mainspring barrel, while the upper part engages with the hands setting wheel.

At least here, you can no longer take of a true Roskopf movements, since there, the hour wheel would also have been driven by the mainspring barrel and not by the hands setting wheel.

On its lower side, the date switching wheel has got a moveable finger. Normally, it is a bit longer than the other teeth and advances the date ring.

Turning back the hands, the date correcting mechanism, which consists of a moveable star wheel and is driven by a changer wheel, ensures, that the date ring is turned forward quickly.

When the long finger of the date switching wheel would engage with the date wheel, which is not wanted here, and so, because it is moveable, it can just move out of position and let the date ring slip through.

This pretty complex calendar mechanism is equipped with well flyable spring and not too easy to service.

The flying parts are covered, so that the operational safety of the calendar mechanism is ensured.

In the lab

Timegrapher result

The rates are not very good. Maybe it’s because of the water damage, maybe it’s because of age and wear. In Average, the large rate differences will more or less neutralize each other.

Technical data

Usage gallery