M 100-5
1964–1965 · 10k Rolled Gold Plate / Stainless Steel · Automatic
About the M 100-5
Made only in 1964, the M 100-5 is part of Hamilton's M Series, a line of automatic dress watches that leaned into clean, understated design. It runs on the caliber 689, a 17-jewel automatic movement, and comes in a 10k Rolled Gold Plate case with a stainless steel back. The silver dial pairs applied baton markers with a sweep seconds hand, giving it a spare, professional look that reads well on the wrist.
Applied baton markers on a silver dial are worth examining closely on any example you come across. The markers themselves can loosen or develop corrosion at their bases, particularly if the watch has seen moisture over the years. The M 100-5 is a straightforward watch in terms of design, but finding one with clean dial and intact markers makes a real difference.
From the Catalog
Hamilton described the M 100-5 as a self-winding watch in 10k yellow rolled gold plate with a stainless steel back, and it retailed for $100 in 1964.
Hamilton Catalog Images
1964
What to Look For
| Dial | Look at each applied baton marker carefully. Check for separation at the edges or dark corrosion at the base where the marker meets the dial surface. The silver dial finish shows age honestly, so look for even patina rather than spots or staining from moisture intrusion. |
| Crystal | Check for deep scratches or a hazy, crazed surface. Acrylic crystals on watches of this era can be polished out if the damage is minor, but a badly crazed crystal will need replacement. |
| Movement | Oil dries out in movements of this age, and the caliber 689 is no exception. Dried oil creates enough friction to stop an automatic entirely. Give the watch some wrist time and see how it behaves before drawing conclusions about the movement's condition. |
| Case | Rolled gold plate wears through at high-contact areas over time. Check the lugs and the back edge of the case for brass showing through. The stainless steel back is more durable, but also note that case backs on this era of Hamilton can be tricky to open without the right tools. |
| Crown | Make sure the crown threads smoothly and seats properly. A sticky or loose crown can point to a worn stem or stripped threads. Also worth noting: even though this watch was originally rated waterproof, no vintage watch should be trusted near water today. |
The Movement
The caliber 689 is a 17-jewel automatic that Hamilton used across a range of dress watches in the 1960s. It winds via a rotor as you wear it, so no manual winding is needed in normal use, though it can also be wound by hand. It is a reliable workhorse movement, though like all movements of this age it benefits considerably from a fresh service.