The caliber M105 bases on caliber M24, but has got the dial mounted onto the date plate and not on the main plate. Because of this, the diameter increased to 13 lignes, this is pretty much, but also allows a larger date ring.
It’s interesting, that even on the same caliber M105, there are differences in the number of holes, on a taiwanese sample, there are fewer holes on the top plate:
The ruby-less pin lever movement has got a two leg anular balance with a rugges v-conic staff, so no shock protection is needed. It beats slowly with 18000 A/h.
The bare dial side shows the rocking bar winding system and the depth-adjustable balance wheel bearing. It also shows the three screws for mounting the movement plate. This means, that this movement is generally serviceable, but it’s not much fun to put the balance wheel, the lever, four gears and the mainspring barrel at the same time under just one plate and fix everything with screws on the dial side!
Unfortunately, the Timex M105 uses just a simple spring as ratchet mechanism - but this spring is not really durable and so, you’ll often find this kind of movement with a broken winding mechanism. If this is the case on the whole M104 series has to be evaluated.
The date indication mechanism is an own module, which is mounted onto the dial plate. The hour wheel drives the switching wheel, which advances date (and day on caliber M106) at the same time, the date can be corrected semi-fast by turning the hands back and forth.
Nickel anular balance|
|Balance bearing / direction hairspring:||Bridge|
|Adjust mechanism:||Hairspring key|
|Winding mechanism:||rocking bar winding system|
|Setting lever spring:||2 hole(s)|
|Functions:||hour, minute, second, day|
|Size:||13''' (measured: 29,5mm)|