I don’t even know if a secondary clutch is a thing, but I recently got 2 older Tombow pencils that are experiencing the same problem.
(I was able to fix one of them, but the other is being stubborn.)
Problem goes like this:
Clicking to advance the lead pushes lead out, but then the lead immediately retracts the exact same amount (so no lead is actually advanced).
If I use a piece of lead short enough, the lead advance works. Once the lead is long enough, it hits something up inside the clutch that’s really grabbing it and not letting go
How can I clean up or de-gunk whatever is up inside the clutch that’s grabbing the lead? Is there a secondary clutch in there? I’ve not encountered this before and am not sure what to do to fix the issue.