Asco 7500

Description

Asco was a german ebauche producer, which made in total only two movements, but did this in different decades and different company structures.
The first Asco, which existed until 1960, was an independant manufacturer of echappements and raw ebauches and mainly supplied Arctos, the second Asco in the 1970 was only a brand name of Arctos itself.

From the 1950s dates the Asco 7500, a form movement with a nominal size of 5 1/4 lignes (in reality 5 3/4 lignes), suitable for the popular tiny rectangular ladies' watches of that era. In the late 1950s it became a bit obsolete and also the rectangular shape was superseded by tonneau shaped and even smaller movements.

The base plate shows its well execution, all important bearings contained rubies and even the minute wheel had on the gear train bridge a ruby bearing, because it was visible here. The same applied for the cap jewel of the escape wheel bearing on the movement side.

In total, the Asco 7500 uses 17 jewels, which promised high quality that time.

As escapement, of course a swiss pallet lever escapement was used.

The gear train uses the standard construction of that time with a pretty large mainspring barrel, center minute wheel, small third wheel, even smaller seconds wheel and a large escape wheel.

For saving space, the lower seconds wheel bearing was located above the escape wheel, a quasi two-storey construction.

The aesthetically beautiful screw balance was not yet shock protected. It beats with 18000 A/h, which could be adjusted with a long regulator arm.

On the dial side, you see the large manufacturers' logo with caliber number, the yoke winding system and the cap jewel for the balance wheel bearing instead of a shock protection.

In the lab

Timegrapher result

The timegrapher result is not so bad for movement of this small size and decades of use. Only the vertical rates reveal the signs of usage.

Technical data

Usage gallery