I can offer no help with your question, but have an interesting story.

I refurbished an older Ugartechea and the safety button looked like a rabbit turd dented to look like a golf ball and pushed onto the safety lever. I just figured while I was refinishing everything I would give it a slightly more attractive shape. I managed to take enough off the ball that it was nearly impossible to move the safety on and off.

lesson learned.
CHAZ