It's not a hammer. Not one of those videos advocate using it to "clap" the seam.
That's how it got the name. Tailors would slam the seam thus making a clapping noise with the wooden block. And it works great to do it that way, really flattens the seam just like the tailor wanted. When I use a tool I like, I research it and discover the why and how of it. Ask me about the seam ripper. LOL I have eididic memory as they call it so only have to read about something once. The way most use it now is because they never knew how it was done anyway. The videos are fine for using the clapper just not the way it was intended.
Last edited by Onebyone; 02-23-2019 at 05:42 AM.