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Hamilton 721
Basic Information
| Name | Hamilton 721 |
|---|---|
| Manufacturer | Hamilton |
| Launch Year | 1939 |
| Is COSC certified | No |
Timegrapher
Beat rate
18,000 bph
Frequency
2.5 Hz
Reference: healthy amplitude ≈ 270–315° fully wound (>200° at 24 h); beat error ideally < 0.5 ms.
Technical Details
| Lignes Dimensions | 5.59 ‴ x 9.33 ‴ |
|---|---|
| Dimensions | 12.6 mm x 21.05 mm |
| Height | 3.25 mm |
| Further Measures | : 4 Mounting Diameter (Dm): 12.6 x 21.05mm Stem height (T): 1.6mm Mounting Height (F): 0.4mm |
| Power Reserve | 36 hours |
| Frequency | 18,000 vph |
| Jewels | 17 |
Complications and Specifications
| Shape | Oval |
|---|---|
| Regulator Type | Pinned Regulator (or Index Regulator) |
| Movement Type | Manual |
| Escapement Type | Swiss Lever |
| Control Type | Balance Wheel |
| Winding Type | Stem Winding (Crown) |
| Setting Type | Stem Set (Crown Pull) |
Additional Information
| Hand Sizes | 1.00 x 0.50mm |
|---|---|
| Hand Count | 2 |
| Country Of Manufacture | United States |
| Notes | Remarks: 1939-1949, 397447 Breguet hairspring Other data: balance staff: U1797 stem: W2096 generations: 995: all jewels in settings 995A: modifications unknown 721: settings only on backside, new stem mechanism balance staff ronda: 1220 (21/0) stem ronda: 1387 (20/0-21/0) |
| Signature | 1945: N264322, Hamilton, U.S.A., 721, 17 Jewels |
| Import Codes |
|
Compatible Parts
17 other caliber(s) share compatible parts with this caliber.
38 compatible part(s) available — Supporter feature.
Metadata
| Created At | Sep 15, 2023 |
|---|---|
| Updated At | Apr 23, 2025, 11:32:55 PM |
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