DuRoWe 270

 
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DuRoWe 270

Description

In the early 1950ies, DuRoWe launched their very successful “Duromat” movement series, consisting of selfwinding movement for gents watches, which was continuously improved and led to many versions of “Duromat” movements.

Around 1960, the long-awaited “Duromat” for tiny ladies’ watches was launched, a truely unique selfwinding movement with a diameter of only 16.2 mm or 7 14 lignes. That’s a bit smaller than a european 1ct coin.

base plate

base plate

The base plate alone shows, how few space was available, but at that time, tiny ladies’ watches were up-to-date. To construct a selfwinding movement with only 16.2mm diameter was a real masterpiece, even when the movement had to build pretty high.

gear train

gear train

The gear train is typical for the 1950ies, it has got a directly driven center minute wheel as well a a directly driven center second wheel.

side view of the gear train

side view of the gear train

The screw balance in beared in two inhouse Duroswing shock protections and beats contemporarily slow with 18000 A/h. A faster beat rate is not possible with that small diameter of the movement.

Durowe 270 without selfwinding module

Durowe 270 without selfwinding module

The selfwinding module is mounted with only two screws. It connects with the ratchet wheel. The base movement without the selfwindig module is nothing but a DuRoWe 260.

bottom selfwinding module

bottom selfwinding module

The selfwinding mechanism consists of the DuRoWe-typical rocking bar changer with two step gear train and a ratchet with ruby-beared click.

bottom oscillating weight

bottom oscillating weight

The bearing axis is part of the quite filigree oscillating weight.

view without oscillating weight

view without oscillating weight

The top of the selfwinding module reveals its construction: The oscillating weight connects with the ruby-beared rocking bar changer (at 3 o’clock), the two reduction wheels are following, with the second one (at 5:30) connecting into the ratchet wheel. The ruby bearing at 6:30 belongs to the ratchet, which prevents unloading the mainspring barrel:

gear train of the selfwinding module

gear train of the selfwinding module

This construction is genious, especially, when you take into account, that the whole movement has got a little smaller diameter than an 1ct (Euro) coin. The drawback is, that it is not really service-friendly. The biggest problem is the small and fragile axle for the oscillating weight, which breaks on harder shocks. And the ratchet, which brakes the first reduction wheel adds some wear to it, since metal grinds on metal.

bottom of the second reduction wheel

bottom of the second reduction wheel

On manual wind, the selfwinding gear train is detached, so that even daily manual wind does not harm the movement. This function is implemented by the second reduction wheel and its two-ratchet clutch coupling. If the drive is rotated in a clockwise direction (in the top view on the underside), it rotates freely, so the selfwinding gear train is disengaged. On the other hand, when the wheel is turned clockwise, the right pawl engages the toothing and the drive is engaged. This is the case when the oscillating weight winds the movement.

Durowe 270 dial side

Durowe 270 dial side

On the dial side, you see the yoke winding system with its setting lever spring and the separated coverin of the changing and time setting wheel.

The escapement wheel (at 9:30) has got cap jewels on both bearings.

In the lab

The specimen shown here was well used, but still working, when it came into the lab, so no service was made.

Timegrapher result

The values show the performance of this movement in unserviced condition, after many years of use and probably even longer storage time:<br/> The rates differ a lot, additionally, the amplitide is pretty low except on the position "dial on top". This is an indicator, that this specimen is due for a service. Nevertheless, the rates will more or less neutralize each other on daily wear.

horizontal positions
dial up +45 s/d 254° 1.1ms
dial down 0 s/d 160° 0.9ms
vertical positions
crown right (12 up) +90 s/d 140° 0.6ms
crown up (3 up) +30 s/d 143° 0.9ms
crown left (6 up) -64 s/d 143° 1.2ms
crown down (9 up) +15 s/d 143° 0.9ms

Technical data

Manufacturer:DuRoWe
Caliber:270
Number of jewels:25
Escapement:Pallet lever
Balance types: Nickel screw balance
Shock protection(s): Duro-Swing
Balance bearing / direction hairspring:Counterclockwise
Moveable stud:no
Adjust mechanism:Long regulator arm
Construction:
  • lever
  • escape wheel, seconds wheel, third wheel
  • center minute wheel
  • mainspring barrel
Construction type:solid construction
Winding mechanism:yoke winding system
Setting lever spring:2 hole(s)
Features:SCD,AUT
Functions:hour, minute, second, selfwinding
A/h:18000
Size:7 1/4''' (measured: 16,2mm)
Literature: Flume: 1962 70
Inventory number:17003

Usage gallery

KH Automatic ladies' watch

KH Automatic ladies' watch

Roxy ladies' watch  (case missing)

Roxy ladies' watch (case missing)