I have converted a prazi 400 mill to cnc with flashcut stepper drive,using 4:1 timing belt speed reduction on steppers.This gives a max feed rate of 8 in per minute. I have stock acme threaded screws. I went with the 4:1 ratio to give greater positioning accuracy and greater torque at low speeds but clearly rapids are limited by slippage to 8 in per minute.What do you all think ,should i have gone with a lesser ratio? What would be the best compromise between speed and torque?