Are tariffs grandfathered?

[Cuddles]

I'm thinking of buying some equipment from China. I can collocate there in the mean time and have it shipped later to avoid getting hit with tariffs but don't know if they apply the day of purchase (grandfathered) or the day I take possession at customs (later);

 

[zdreg]

the newspapers mentioned that companies are rushing to have goods delivered before tariffs take effect. imagine the fraud if it was based upon purchase date.
here is an explanation in reverse for exports
https://2016.export.gov/logistics/eg_main_018130.asp
it will apply to imports the US.

in any case call a custom's office or any import forwarder to confirm.