Elgin 685 Navigation Hack
- Brand: Elgin
- Product Code: Elgin 685 Navigation Hack
- SKU: 2292-115
- Availability: In Stock
Ex Tax: $495.00
Elgin 685 navigation hack in 1917-H case. Movement is a caliber 685 with 18 jewels, hacking with center sweep. Dial is an EL 1234-1669 type with luminous numerals and dots at each hour graduation and inner 24 hour chapter. The outer seconds graduations were marked with small numerals at each 10 second interval. This is probably my favorite navigation hack dial with luminous numerals, dots and elongated luminous hands.
Elgin 685 had the Double Sweep Second Wheel, on the 685, as well as the 630, 716, and 724, though on those the wheel(s) are under a bridge. Indirectly driven sweep second hands will jump ahead, stall, jump ahead, stall, etc unless some means is provided to keep the pinion perfectly meshed with the wheel driving it. The double sweep second wheel has one wheel fixed to the hub, and the other wheel loose. The loose wheel connects to the hub via a spring. When installing the sweep second pinion, you first install the double wheel, then turn the loose wheel 4 or 5 teeth against the spring tension, then install the pinion while holding it. When you release, the leaves of the pinion are held against the teeth of the fixed wheel and cannot jump ahead.