Seiko Epson Caliber VX42E Watch Movement

Manufacturer	S. Epson Corp. (Seiko Instruments Inc.)
Caliber Number	VX42, VX42E
Seiko Number	7N42, 7N42C
Movement Type	Quartz, battery operated
Display Type	Analog
Lignes	11.5”’
Diameter	25.6mm
Height	2.62mm
Jewels	0
Frequency	32,768 Hz
Battery Cell	SR920SW (371/373)
Battery Life	3 years
Accuracy Rating	+/- 20 seconds/month
Regulator	None (adjusted from factory)
Stem	351177 (tap 10), also 351892 (tap 11)
Hand Sizes	1.1mm / 0.65mm / 0.2mm
Hand Count	3
Functions	Central hours; central minutes; central seconds; date at 3:00 (or other locations depending on dial design)
Hacking Seconds?	Yes
Quickset Calendar?	Yes
Other Functions	Low battery indicator (EOL)
Country of Manufacture	Made in Japan
Known Models	(Add your watch to the comments below…)

S. Epson caliber VX42E (VX42) is a 3-hander quartz watch movement with a date calendar complication.

Official tech docs for this caliber were found dated as recently as September 20, 2020, with original dates as far back as February 24, 2014.

Some of the topics covered in this caliber listing:

VX42E VS VX43E:

There is a similar caliber VX43E with the only difference being that the VX43E has a day/date and the VX42E only has a date.

Seiko 7N42 VS VX42:

There is a similar Seiko caliber 7N42 that basically just a Seiko branded version of the Epson VX42 (Epson is a division of Seiko Time Corp). The 7N42 was introduced around 1993 and remained in production into the 2000s. Although the Seiko is available from watch parts sellers, the Epson VX42 tends to be sold wholesale at lower prices to parts sellers and other watch brands.

Whiles these movements are often considered by the community to be interchangeable, that should not be the automatic assumption. There are some interesting things to note based purely off of technical information provided by Seiko (not confirmed by real world testing):

Note: the difference in height could be due to Epson including the installed battery in the measurement. It is unconfirmed whether Seiko’s height quote is with or without the battery.

Other differences in specs are that the Epson documentation makes no mention of having the train wheel setting device or electronic circuit reset switch that the Seiko has.

	Epson VX42	Seiko 7N42
Trailing Letter	E (VX42E)	C (7N42C)
Height	2.62mm	2.78mm
Battery Life	3 years	5 years
Jewel Count	0	1
Accuracy Rating	+/- 20 sec/month	+/- 15 sec/month

If you want to create a watch with one of these special designs, you should use the drawings in the tech sheets pdf (below) for the measurement guidelines.

There also appears to be a high-hand version for thicker dials: calibre VX42MH2.