HMT 0231
Description
As a license build, probably in the 1970s, the caliber HMT 0231 was launched. It was an almost 1:1 copy of its original model, the Citizen 0201.
Just like that, the HMT 0231 only uses a three-hand time indication with directly driven center second hand.
base plate
The base plate of this 11 1/2 ligne movement is aesthetically so la-la, but technically, it has got everything, a good movement requires, and even the minute wheel is ruby-beared, just as all other pivots of the gear train.
base plate with minute wheel
Its origin, the Citizen 0201 dates from the early 1960s, and so the gear train is typical for that time with a directly driven center minute wheel, beared under its own bridge.
gear train
The remaining gears of the gear train bear no surprises, the minute wheel is followed by third wheel, directly driven center seconds wheel and finally the escape wheel, into which the swiss pallet lever escapement engages.
side view of the gear train
As regulating device, a two-leg Glucydur anular balance is used, which is beared in a pair or Citizen Parashock bearings. The balance beats slowly with 18000 A/h and is regulated directly at the hairspring key.
HMT 0231: Dial side
On the dial side, you can spot the yoke winding system with its noticeable bent setting lever spring.
In the lab
Timegrapher result
Heavily used and only simply cleaned shows this movement a sub-average performance on the timegrapher. Technically it would be able to perform much better.| horizontal positions | |||
|---|---|---|---|
| dial up | +85 s/d | 188° | 1.0ms |
| dial down | -1 s/d | 293° | 3.2ms |
| vertical positions | |||
| crown right (12 up) | -77 s/d | 167° | 3.1ms |
| crown up (3 up) | -54 s/d | 174° | 2.2ms |
| crown left (6 up) | +140 s/d | 155° | 4.7ms |
| crown down (9 up) | +37 s/d | 177° | 4.2ms |
Technical data
| Manufacturer: | HMT |
| Caliber: | 0231 |
| Caliber base: | Citizen 0201 |
| Size: | 11 1/2''' (measured: 25,65mm) |
| A/h: | 18000 |
| Escapement: | Pallet lever |
| Balance types: |
Glucydur anular balance (two legs) |
| Shock protection(s): |
Parashock 1 (Citizen) |
| Balance bearing / direction hairspring: | Clockwise |
| Moveable stud: | no |
| Adjust mechanism: | Hairspring key |
| Construction: |
|
| Construction type: | solid construction |
| Winding mechanism: | yoke winding system |
| Setting lever spring: | 2 hole(s) |
| Attachment of setting lever: | plugged |
| Features: |
|
| Inventory number: | 23057 |
Usage gallery
HMT Vivek gents watch