What is the difference between ETA/Unitas caliber 6497 and 6498?
Both movements are based off of pocket watch movements. Both movements are found in many modern day pilot/flieger watches. Both movements were introduced in 1950 and are still being manufactured today. This is only one major difference…
| Caliber 6497 | Caliber 6498 | |
| Origin | Swiss made | Swiss made |
| Year Introduced | 1950 | 1950 |
| Diameter | 16.5”’ (36.5mm) | 16.5”’ (36.5mm) |
| Height | 4.5mm | 4.5mm |
| Jewels | 5/17 | 15/17 |
| Power Reserve | 46-50 Hours | 46-50 Hours |
| Beats Per Hour | 18,800/21,600 vph | 18,800/21,600 vph |
| Date? | No | No |
| Hacking? | No | No |
| Crown | Counterclockwise to set time | Clockwise to set time |
| Regulation | Etachron | Etachron |
| Anti-Shock System | Incabloc (or none) | Incabloc (or none) |
| Small Seconds Location | 9:00 | 6:00 |
The major difference between the Unitas/ETA caliber 6497 and caliber 6498 is the location of the small seconds subdial.
Sub seconds placement, that’s all folks!
Imagine these watches as the were intended: as pocket watches. The 6497 would be in a Lépine (open face) pocket watch with the crown up. The 6498 would be the movement in a hunter style pocket watch with the crown to the right. Both would have the seconds at the 6:00 mark, but changing the crown position by 90 degrees would change the seconds position as well. When used on a standard wristwatch, this gives two options for the seconds placement when designing the dial.
Part Interchangeability
There are some differences in parts as well. This was outlined by lysanderxiii on wus:
The 6497-1 and 6498-1 (same for the -2) do not share commonality in the following parts: (all others common)
- Mainplate
- Barrel Bridge
- 3rd Wheel
- 4th Wheel
- 4th Wheel (no second pinion)
- Stem
- Set Lever
- Setting Lever Jumper
- Yoke (-2 variants only)
Which one is more popular?
Do you know of more pilot watches with the small seconds at 6:00 or 9:00? It seems that there are more 6:00 subdials out there, making the 6498 more popular. However, with that said, you may find that more listing mix these movements up and list most watches as having the 6497 without actually knowing the difference. Hopefully this post will change that!
What is the difference between calibers with “-1” or “-2” at the end?
Click here to read more on that.
Have you noticed any other differences? Please comment below.
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