Oris 90P

 
Oris 90P

Oris 90P

Description

Before Oris became popular for their “High Mech” line with ETA movements, they produced inhouse movements for many decades, mainly pin lever movement in different qualities.

One of their early movement, which was quality-wise rather on the lower end, is the caliber 90P shown here, a simple but rugged pin lever movement in Roskopf construction.

base plate

base plate

The simple brass plate uses no jewels, only drilled brass bearings and two steel bearings for the balance staff.

The way, the winding wheel is held in position is really freaky: The upper gear train bridge is slanted below the crown wheel and bent down, so that the winding wheel cannot move lateral:

"Bearing" of the winding wheel

"Bearing" of the winding wheel

The clutch wheel and the winding stem are beared in a metal cage, which became porous over the years. On the following photo, you see, that half of the cage is mising:

gear train

gear train

The gear train is typical for a Roskopf construction:

The large mainspring barrel overtops the center of the movement, and is followed by the second wheel, third wheel and escape wheel.

Compared with “normal” lever movements, it has got one less transmission step.

side view of the gear train

side view of the gear train

Due to the missing transmission stage, the beating rate has got the odd amount of 17280 beats per hour, which can be adjusted as far, as technically possible, with a long regulator arm. The not shock protected anular balance has got a rugged balance staff. It engages with a pin lever.

lever

lever

The lever is pretty simple and only punched, but has got a beautiful shape.

mainspring barrel with slip clutch

mainspring barrel with slip clutch

As with any Roskopf construction, the hands are driven exclusively on the dial side by the double gear, which sits, connected with a slip clutch, on top of the mainspring barrel.

dial side without hour wheel

dial side without hour wheel

The lower, larger sprocket drives the small minute tube with the minute hand on, the small upper sprocket the big hour wheel.

Oris 90P: dial side

Oris 90P: dial side

It’s a bit surprising, that the Oris 90P already uses a yoke winding system. The hands setting wheel engages here with the large sprocket of the double gear on top of the mainspring barrel.

At 7 o’clock, you can see the cutout for the lever bearing. With some force applied, it can be “adjusted”, so that the lever pins engage properly with the escape wheel. A pragmatic, but efficient solution.

In the lab

The movement came gummy into the archive and was cleaned and olied, but only with limited success. The bigger problem, the broken winding stem cage, could not fixed.”

Technical data

Manufacturer:Oris
Caliber:90P
Escapement:Pin lever
Balance types: Nickel anular balance
Shock protection(s): none
Balance bearing / direction hairspring:Counterclockwise
Moveable stud:no
Adjust mechanism:Long regulator arm
Construction:
  • lever
  • escape wheel, third wheel, large driving wheel, mainspring barrel
Construction type:pillar construction
Winding mechanism:yoke winding system
Functions:hour, minute
A/h:17280
Size:13''' (measured: 29,3mm)
Inventory number:19017

Usage gallery

Bentima gents watch "The Best Shock-Proof Lever"

Bentima gents watch "The Best Shock-Proof Lever"

This movement and watch is a kind donation from Philipp Porter. Thank you very much for supporting the movement archive!

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