AM 630

AM 630 | - The Movement Archive

AM 630


From AM, mainly round movements are known, and so the 6 3/4 ligne form movement AM 630 is a little speciality. It impresses expecially due to its beautifully slanted gear train bridge.

AM 630: base plate

base plate

On closer inspecition, you can see, that all important bearings contain rubies. Interestingly, the four dial side bearings for the balance wheel, the lever, the escape wheel and the seconds wheel are made of transparent jewels. These are the bearings, you normally don’t see when you open the back of the watch.

Another noteable detail is the wasted space due to the small mainspring barrel. The shape of the caliber 630 would have made a much larger mainspring barrel possible, no idea, why it wasn’t used.

AM 630: gear train

gear train

We have the usual gear train here with mainspring barrel, center minute wheel, third wheel, seconds wheel and escape wheel.

As escapement, a swiss pallet lever escapement is used.

AM 630: side view of the gear train

side view of the gear train

The balance of this 1920s constructed movement is bimetallic with a slotted hoop. It is of course not yet shock protected and beats with the usual 18000 A/h. With the help of a long regulator arm, the effective length of the hairspring can be adjusted.

AM 630: AM 630: Dial side

AM 630: Dial side

Of course, the AM 630 uses a yoke winding system; the setting lever spring of the specimen shown here is broken, as well, as the (but not visible on the photos) dial side bearing jewel for the balance wheel.

In the lab

The movement came without case into the lab and got a simple service.

Timegrapher result

The rates indicate, that the movement is in poor condition, probably mainly due to the broken bearing jewel for the balance wheel. Because of this, no further adjustment was done here.

horizontal positions
dial up +80 s/d 187° 4,4ms
dial down +136 s/d 222° 4,2ms
vertical positions
crown right (12 up) +160 s/d 193° 3,9ms
crown up (3 up) +100 s/d 231° 3,4ms
crown left (6 up) +-0 s/d 202° 4,6ms
crown down (9 up) +80 s/d 216° 4,9ms

Technical data

Caliber base:AM 630
Size:6 3/4''' (measured: 15,0 x 24,5mm)
Escapement:Pallet lever
Balance types: bimetallic screw balance (two legs)
Shock protection(s): none
Balance bearing / direction hairspring:Clockwise
Moveable stud:no
Adjust mechanism:Long regulator arm
  • lever
  • escape wheel
  • seconds wheel, third wheel, center minute wheel
  • mainspring barrel
Construction type:solid construction
Winding mechanism:yoke winding system
Attachment of setting lever:screwed
Setting lever spring:2 hole(s)
References: Ebauches: 1928
Inventory number:23007

Usage gallery

AM 630: anonyme ladies' watch  (case missing)

anonyme ladies' watch (case missing)

This movement is a kind donation from Rolf to the movement archive. Thank you very much for your great support!

Caliber Family
AM 630

Other movements from AM