Or better still not bother and buy some cheap Acme lead screw with a more fitting Dia and pitch. You'll nail several birds with one screw.!! So to speak.

Threaded rod is a multi edge gotcha sword in that the pitch is small which requires you to spin it fast and still get low speeds. The Thread is poor and abrasive which at high speed wears nuts away very quickly. The thread pitch varies wildly along it's length so isn't accurate. It's highly inefficient so zapping motor torque which you don't have spare because the motors have to spin fast just move at what is a relatively low feed rate.

If you can't afford ballscrews then Lead screw is the next logical choice. Threaded rod isn't and shouldn't even be considered other than for bolting the frame together.!!