EB 8461

 
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EB 8461

Description

The manual wind, medium sized pin lever movement EB 8461 was released in the 1970ies. Due to its rational construction, which left out all unneccessiary details, it was rather cheap and so used in fashion watches, among them the direct read watches, which were “in” that time. The version with direct read indication is presented here.

Video on YouTube
base plate

base plate

The EB 8461 is a Roskopf like construction, which means, that the hands are only driven by the mainspring on the dial side, and not, like on non-Roskopf movements, on the movement side. The only exception is the directly driven center second.

gear train

gear train

The gear train is driven by the mainspring and consists of second wheel, third wheel, fourth wheel (which carries the center second hand) and escapement wheel.

side view of the gear train

side view of the gear train

The flat three-leg ring balance is beared in two different shock protections with metal bearings. On the dial side, it’s of unknown type, on the movement side it’s the pretty unusual Novochoc system. The only ruby on this movement is the finger of the balance. The balance still ticks with slow 18000 A/h.

inside the gear train bride

inside the gear train bride

The inner side of the gear train bridge hosts the odd winding click mechanism, which consists only of two parts, a U-shaped spring and a gear. Both are riveted and cannot be replaced.

On the EB 8461, we have a yoke winding system. It’s made in a rather simple construction, but it works well. The hand setting gear on the dial side is also riveted.

dial side, yet without direct read indication

dial side, yet without direct read indication

You can spot the hand setting wheel, which is drives the upper mainspring barrel wheel. This wheel is attached with a slip clutch onto the mainspring barrel and drives the minute cannon pinion. Unlike on true Roskopf movement, the hour wheel is not driven by a reverser on top of the mainspring barrel, but with own reverser wheel, located at “7”.

On the version with direct read indication, there’s no classic hour wheel, but a hour disc, which is driven by a three-teeth reverser wheel.

dial side with reverser wheel for the direct read indication

dial side with reverser wheel for the direct read indication

The direct read indication consists of a constantly driven minute disc, on the minute cannon pinion and a hour wheel with 12 teeth on its inner side which is advanced once per hour by the reverser wheel.

under the hour disc...

under the hour disc...

To esure proper switching and engagement, a punched spring is used:

punched spring for the direct read indication

punched spring for the direct read indication

When both discs are mounted, you hardly see anything else of the dial side:

EB 8461 Digital Zifferblattseite

EB 8461 Digital Zifferblattseite

In the lab

The specimen shown here was like new, but completely dried out and maybe someone wanted to fix it with improper fluids and oiled/gummed and bent the hairspring. With a full service, the movement could be brought back to life, only the bent hairspring caused distortions on the timegrapher. Nevertheless, the movement performs very well with a (positive) deviation of less than one minute per day, which is very well for a pin lever movement with formerly bent hairspring.

Technical data

Manufacturer:EB
Caliber:8461
Number of jewels:1/17
Escapement:Pin lever
Balance types: Nickel anular balance
Shock protection(s): Novodiac
Novochoc
Balance bearing / direction hairspring:Clockwise
Moveable stud:yes
Adjust mechanism:Hairspring key
Construction:
  • lever
  • escape wheel, seconds wheel, third wheel, large driving wheel, mainspring barrel
Construction type:pillar construction
Winding mechanism:yoke winding system
Features:(SCD),(QG)
Functions:hour, minute, (second), (day)
A/h:19800
Size:8 1/2''' (measured: 19,3mm)

Usage gallery

Eloga ladies' watch

Eloga ladies' watch