Ronda 1011-21
Description
The Ronda 1011-21 is part of the 10xx family of windup movements in a Roskopf-like construction. It reduces the base caliber Ronda 1013 by removing the center seconds indication, and increased the beat rate to 21600 A/h.
With a diameter of 10 1/2 lignes, it has got the universal size, which makes it usable for gents and ladies' watches at the same time.
base plate
The execution of the Ronda 1011-21 is well, you only won’t find any bearing rubies, so that all pivots run in simple drilling holes.
There are even no ruby bearings for the balance wheel, and as a kind of shock protection, to plastic bearings are used.
gear train
The gear train with its missing center seconds wheel is quite like that of a Roskopf movement. Here, the mainspring barrel drives the large driving wheel, followrd by third wheel, directly driven center seconds wheel (shortened axle on caliber 1011) and the escape wheel.
empty dial side
As usual on Roskopf movements, the hands are driven by the outer gears of the mainspring barrel.
The difference is, that we have a double cannon pinion, whose outer one carries the minute hand and interacts with the changer wheel. The inner/lower one interacts with the barrel.
sial side with double mainspring barrel
Even though the Ronda 1011-21 is just a pin lever movement, you must confess, that it is pretty well made, like all Ronda movements, and of course, it has got a yoke winding mechanism.
Ronda 1011-21: Dial side
At position 7 o’clock, you can see the almost invisible dial side plastic bearing for the balance wheel axle.
In the lab
Timegrapher result
Although after adjustment, it still runs too slow, the positional deviations are accetable for an almost jewel-free pin lever movement.| horizontal positions | |||
|---|---|---|---|
| dial up | +-0 s/d | 251° | 0.7ms |
| dial down | -30 s/d | 255° | 0.4ms |
| vertical positions | |||
| crown right (12 up) | -10 s/d | 250° | 0.9ms |
| crown up (3 up) | -36 s/d | 243° | 0.3ms |
| crown left (6 up) | -55 s/d | 231° | 0.2ms |
| crown down (9 up) | -45 s/d | 235° | 0.8ms |
Technical data
| Manufacturer: | Ronda |
| Caliber: | 1011-21 |
| Caliber base: | Ronda 1013 |
| Size: | 10 1/2''' (measured: 23,3mm) |
| A/h: | 21600 |
| Number of jewels: | 1 |
| Escapement: | Pin lever |
| Balance types: |
monometallic anular balance (two legs) |
| Shock protection(s): |
none |
| Balance bearing / direction hairspring: | Counterclockwise |
| Moveable stud: | yes |
| Adjust mechanism: | Hairspring key |
| Construction: |
|
| Construction type: | solid construction |
| Winding mechanism: | yoke winding system |
| Setting lever spring: | 3 hole(s) |
| Attachment of setting lever: | plugged |
| Inventory number: | 23028 |
Usage gallery
Meister-Anker ladies' watch