I haven’t tried this yet myself, but here is a good video on creating a rubber stamp with a K40.
Love this. I struggled with inverting the colours and used my vinyl cutter software then exported, converted to svg then laser cut. Now I see I can do in K40 whisperer. I agree that you need to experiment with the power and that buying good quality laserable rubber is important.
I found that thingiverse has some templates for laser cutting wooden handles.
Worked ok for me.
From long past the K40’s main purpose was to do stamps!