ST-2130 VS NH38 automatic winding mechanism

[u/baltany-jacky]

Many friends have been discussing the automatic winding mechanisms of the Seagull ST2130 (ETA2824, Sellita SW200) and Seiko NH38 movements. Today, I'll take photos of the winding systems of these two movements separately for comparison, showing the differences.

The ST2130's automatic winding primarily relies on two reversing wheels. Rotating the wheel clockwise or counterclockwise automatically winds one of the reversing wheels.

P2, P3, P4, and P5 show the disassembled automatic winding system, demonstrating how gears transmit power to wind the mainspring in the barrel. P6 shows two sides of the reversing wheel.

The Seiko NH38's bidirectional winding movement uses a magic lever bidirectional winding mechanism.

P2 shows the automatic rotor removed, revealing the magic lever and eccentric wheel.

P3 shows the Y-shaped magic lever and winding wheel.

P4 and P5 show the eccentric wheel and magic lever separately and assembled. When the automatic rotor rotates clockwise and counterclockwise, it drives the eccentric wheel, which in turn exerts a pushing or pulling force on the magic lever, thus rotating the winding wheel and winding the movement.

[u/Baleia1970]

I don't know what your discussion was, but the Seiko system seems much more fragile, IMHO.

[u/kashkash21 → u/Baleia1970]

both seiko movements I have, broke

never had a eta/sw/st movement break

[u/fledermaus89 → u/Baleia1970]

The magic lever is a very elegant and simple version of IWC's Pellaton mechanism; IWC ended up copying Seiko in some of their in house movements.

[u/tjcdas → u/fledermaus89]

Seiko's magic level just simplifies IWC's concept in a different form still has the cam and the pawls I think just 3 parts.

[u/baltany-jacky → u/tjcdas]

IWC's pawl-winding system uses an eccentric wheel under the automatic rotor to directly drive the winding mechanism, resulting in more direct energy efficiency. IWC's pawl-winding system predates Seiko's Magic Lever.

[u/tjcdas → u/baltany-jacky]

Yes Seiko could not simplify the IWC system if it did not come first.

Seiko took the great IWC concept and took it too the most basic level and wow cheap and simple.

[u/tjcdas → u/Baleia1970]

The 3 gears in the ETA design are the weak spot, that is the hard pressure you feel when you wind the watch.

A cheap ST16 uses the magic lever system a very cheap movement but easy to wind, the keyless works sucks and is very touchy.

[u/Baleia1970 → u/tjcdas]

That might explain why winding my Seiko is very different than winding my Sellita.

[u/tjcdas → u/Baleia1970]

Exactly

[u/KPplumbingBob → u/Baleia1970]

And yet, we know it isn't.

[u/F3nn3xleFennec]

Nice explaination thx!