Thread adapters larger than 1/2"

I have a 1/2-20 stud that I need to step up to a 3/4-16 stud. I searched around for 1/2-20 female to 3/4-16 male thread adapters, but was only able to find such a product on McMaster for sizes 1/2 and smaller. Are there "thread adapters" (assuming that’s what they’re called) for larger sizes? If so, does anyone know where I can buy them?