The fitting would work fine provided it is machined to the specifications it claims. ... FPT (aka MNPT aka FIP) - Female Pipe Thread (aka Male National Pipe Thread aka Female Iron Pipe).

Glue a 1-1/2-inch PVC x 3/4-inch FIP adapter (A) onto a female PVC trap adapter (B). Note: This allows you to attach your shop vacuum to 3/4-inch pipe. The barbed fitting (C) connects to 1/2-inch ...