A release  poppet with long, O-ring for dry type.

Because I did not hardening  head of it,It got dented and the clutch became hard to turn off .

So make it with SKS 3,harden it hardening.
This is newly made.

It was broiled with acetylene,The moment when the color changed from red to orange,sink in oil.

It went well.
It became hard enough for the file to slide.