Thumbwheels (aka: finger roll) are typically loose. Not a 1/4" loose but loose nonetheless. Usually, the outer flange in press fitted to the hub and inner flange.
Having said that, I'm sure it's labelled S&W but it's not anything manufactured by S&W. It's a S&W badged caliper made by someone else and probably not a high quality product li8ke Starrett, Brown & Sharpe, Mitutoyo or Fowler.
When buying measuring tools, it's always better to buy brands that are actually made by companies that specialize in measuring instruments, not in firearms or reloading components.
For example, you can buy a 6" Starrett dial caliper 0.001 in solid stainless, is/os measurements with a depth rod and covered rack for less than a hundred dollars and it will outlast you..... or me.