If it is anything like importing to Canada, just show up at the border with the lathe and a proper receipt. Either you get someone who just asks about the lathe, or they send you to secondary and they figure out how much tax and duty you pay.
What I sometimes do is call or stop at customs on my way and ask what to have when you bring it across.
Not all border crossings allow commercial imports. At least into Canada. Rainbow Bridge is one as well as the lower bridge which is Nexus only. In Niagara anyways.
In my experience, if you have a receipt for a used machine, I have rarely paid any duty or tax if any. This is going the opposite way you are going.
Also your money is worth $1.32 to our $1.00. Makes it more worth the drive.
Martin