AHO 555

Description

A rare specimen of the elongated 5 1/4 ligne form movements is the AHO 555 from Pforzheim im Germany, which was made around 1960.

It is impeccably crafted, even using a cap jewel on the upper escape wheel bearing and a bearing jewel for the upper minute wheel bearing, in reference to the very important and effective advertising number of 17 stones.

The AHO 555 uses the conventional gear train with directly driven center minute wheel, followed by the really tiny third- and seconds wheel and finally a rather large and very filigree escape wheel.

Due to the limited space, which this kind of movement offers, the dial side bearing for the seconds wheel is located half-high, above the escape wheel.

The ADO 555 uses a swiss pallet lever escapement and a not yet shock protected balance wheel with screws (in 1960 this was no more up to date), which beats contemporarily slow with 18000 A/h. The adjustment can be made on the hairspring key only.

On the dial side, the AHO hallmark is easy to see, everything else is pretty unspectacular. The yoke winding system, which is used here, is standard.

In the lab

Timegrapher result

For a well used, about sixty year old movement, the rares are acceptable, but indicate the need for a real service or spare parts, e.g. a new mainspring. The almost non present beat error is impressive, since the hairspring stud is fixed and the beat error cannot be adjusted.

Technical data

Usage gallery