Specs required for watch stem

[Guest Teedotyyz]

Can someone advise what size of stem is required for an Asian Auto 21J movement? I have checked Ofrei and E-Bay but do not know what size is required or if I need an extender. I snapped mine clean in half and have sourced a new crown but cannot get the stem. It is the only thing left to put a project watch back together. Thanks. Tim.

[sssurfer]

Hi, you need a caliber 90 stem (0.90 mm diameter).

But if you actually snapped your stem in half then an extender might not work, you might need a brand new stem.

The extender works good when the stem is just cut short on its crown end, so that you just need a short extender.

That is because the extender's female end is a swelling end that can't go deep into the movement, it needs to stay inside the spacer ring between the movement and the case wall.

Hope this makes sense.