The Rolex caliber 1570 shown here was found in a vintage Rolex Date 5.3 million series from the late 1970s (pics soon). It is automatic movement based on the caliber 1570 which was introduced in 1965 and used until around 1974.
Although you might see many sites listing a few variations of 1570 series depending on complications (ie: 1575 with a date; 1575 GMT with a date and GMT hand; 1580 which is anti-magnetic and used in the Milgauss), the truth is that many caliber 1570 movements have the date. If you open your Rolex Date reference 1500 watch, you are likely to find a caliber 1570, not a 1575.
Is the cal. 1570 COSC?
Yes, the caliber 1570 is a certified chronometer (COSC) movement.
Differences between the caliber 1560 and 1570?
The Rolex caliber 1560 was produced around the same time as the 1570, however, it beats at a lower 18,000 bph. It is also a certified chronometer.
Randall on TZ posted some enlightening information about the difrerences between the Rolex caliber 1570 series and the caliber 3135 (some typos were corrected for readability):
OK, first to consider is the beat rate, the 1570 beats at 19.8KBPH, much slower than the 28.8KBPH of the 3135. All things being equal, a higher resolution will net better accuracy.
Although the technical engineering is quite similar in both movements, such as freesprung balance, and hairspring overcoil, the 3135 shows many technical upgrades, such as the aforementioned beat rate.
The 3135 now uses a laser poised balance, instead of poising by means of screws, much better. The 3135`s balance now has both fine and gross regulating adjustments via the microstela screws (4 screws), the 1570 only uses two such screws.
The 3135 now uses a direct seconds layout of the train, instead of the somewhat finicky tension adjustment of the in-direct seconds layout used in the 1570.
The 3135 now uses a balance bridge, with adjustable studs for balance staff end shake. Although this can be adjusted on the 1570, it can not be done while the movement is running, as it can now be done on the 3135.
The rocking transmission wheel for handwinding in the 3135 replaces the wolfs teeth clutch wheel found on the 1570. A clutch wheel wears, a rocking wheel doesn’t.
While some may say the 1570 and its variants were the last handmade Rolex, and therefor show more craft, I disagree with this, as craft is found at many different levels. When craft starts at the drafting board, and carries itself all they way through modern production procedures, I feel it does add more value to the end user.
When a knowledgeable watchmaker looks at and compares these two movements, he sees that Rolex has never stopped pushing the envelope with mechanical movements, and although the family resemblance is there between the two movements, the 3135 has become much more knowledgeable and astute in the way it is made.