An Introduction to the GMT Compass

Point NORTH.

Following the MARTIN M-130 Limited Edition release in 2018, the became the second automatic GMT timepiece available in the Chesapeake Collection. Featuring the same vintage style of American aircraft instruments as its sister chronograph. 

During daylight hours, the watch can be used as a compass. When the 24-hour hand is set to the same timezone as local 12-hour time, and the 12-hour hand is directed to the sun, the 24-hour hand points North.

Designed as a sports-watch to be worn by active, sports-oriented, successful people with style. Aiming to attract attention when visible on the wrist. Built as an everyday item that expresses its owner’s dynamic lifestyle and sophisticated taste.

The GMT is clean and readable in both the day and night. Indicating hour, minute, and sweep-second from the center. The 24-hour hand can be individually adjusted to a different time-zone than the 24-hour hand. The Arabic numerals have a good readable contrast to the matte black background. The hour markers are dots with a luminous layer. At 12 o’clock is a luminous filled triangle to mark the 12 o’clock position at night time. The minute and hour hands are designed after the hands found within the Martin M-130 aircraft from 1935. 

Pantone 5793 U is a recipe developed in-house by Hartwig Balke. Composed of SuperLuminova that stores light from the sun during daytime to glow at night. The recipe was created specifically for the MARTIN M-130 and to complement the unique high-contrast palette featured on the dials.

The 41mm stainless steel case features smooth and clean edges while retaining a raw handcrafted feel. The lugs are bent down so that smaller wrists are able to wear the watch comfortably and that the end parts of the leather strap are still visible when looking straight down at the watch. The width between the lugs is 20mm in order to allow installation of standard leather bands or NATO straps. The bezel has a similar groove pattern as the Skipjack GMT, slightly bigger in diameter than the case midsection. The sapphire crystal is domed with double-sided anti-reflex coating. The exhibition back has a flat sapphire crystal to show the mechanics of the movement. The steel border bears important customer information such as the Reference number NP250, unique serial number 1-250, 50m ATM, and manufacturers name & location. Engraved with Towson’s inhouse laser machine. 

"3-Piece" CASE = Lifetime Guarantee

The 41mm stainless steel case on the is composed of three parts - bezel, midsection, and caseback. All three sections are screwed together - bezel screwed down, caseback screwed down. The lugs are hand-machined. The surfaces between the bezel/midsection and caseback/midsection are sealed by O-rings. This three-part case composition allows for easier cleaning and servicing, ultimately, guaranteeing the sports-watch for a lifetime.

Having the three case components machined and assembled as separate pieces allows for easier servicing. This is because the watch can be disassembled and each component can be treated by the watchmaker accordingly. For example, if the watch bezel is severely scratched, but the midsection looks fine, we can take apart the two and polish the bezel without disrupting the finish, lines and shape of the midsection.

DEVELOPMENT: Mounting the Movement

Caliber 2893-2 is sourced "as-assembled" from a proprietary partner in Switzerland to be taken apart, reassembled, decorated and calibrated by Towson watchmakers in Baltimore, MD. Once completed for final assembly into a Towson Watch, the dial and hands are executed from the front by hand. The mounted case bezel secures the dial in a horizontal and vertical direction. The winding stem secures the movement from rotating. The movement is secured through mounting plates (engineered inhouse) and screws to the case midsection. 50 meter water resistance is achieved with a standard push-pull crown tube.

The flat sapphire crystal exhibition caseback has six machined gaps evenly distributed on the circumference for the opening key. The satin-finish steel border is engraved using Towson's specialty laser engraver.

MAKING THE DIAL: Technical Requirements

A brass blank with .5mm thickness is blasted with sand to create a nice smooth matte surface. The yellow numerals and hour markers are printed in Pantone 458 U with the minute circle printed in Pantone 3265 U and the 24-hour circle printed in Pantone 3265 U. A Super Luminova coat in Pantone 5793 U overlays the hour dots and hands. The date window at 6 o'clock has a red background in Pantone 1807 U with black date numbers. The dial feet diameter, location and length is modified from the standard Caliber 2893-2 positioning in order to fit the in-house movement plates.

All Pantones developed by Hartwig Balke in Baltimore, MD.

MAKING THE HANDS: Technical Requirements

The hands are made of steel with the hour & minute hands painted in color Pantone 458 U. They have a flat profile and the center arbor is painted in black. Skeletonized to feature a window filled with SuperLuminova Pantone 5793 U. The sweep-second hand is painted in red Pantone 1807 U with a length .5mm longer than the minute-hand. The arbor of the sweep-second hand is made from a softer material (brass) to ream the seat according to shaft dimension.

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