My thumbpiece on my 586 has what looks like rust in the checkering.I ordered a new one to replace it.I have never worked on a S&W revolver.Is there anything I need to know involving swapping out the thumbpiece. Thanks

Just unscrew it,lift off the old one and put the new one on.I actually lost a thumbpiece on a fishing trip.

Just like arjay said, unscrew, using a properly fitting screwdriver, remove & replace. Remember you're just installing a thumbpiece so don't get too carried away when tightening the new one down.

Because the shape of the newer thumbpiece digs into the web of my wife's hand on her J Frames I've replaced the newer style with the older, more rounded type, on all her J's.

Since then she hasn't had any problem whatsoever.

__________________
Ogy

If the rust happens to another gun or happens to the new thumb piece you just bought, take an old stiff toothbrush and some gun oil and it will remove it.

If the rust persists, you can remove the thumb piece and clean off the old bluing and re-blue it. Cold bluing is not as durable as Factory Hot Blue, but it might be enough to solve your problem.

Chief38

Thanks for the info.