Hello.
I was wondering if there is a special tool besides using some pliers to tighten Sanwa and Seimitsu screw in buttons?
Technically the Happs button wrench is said to work on Sanwa screw-ins but not Seimitsu.
Although it does not work as well since the Happs wrench does not grip the sanwa nut as easily.
I sometimes use a screw driver to push the notches on Seimitsu tighter.