When I jog thru the area where the majority of the time the z-axis operates during a job it makes a howling noise. Like a loose fit and dry so it can vibrate and make the noise as it travels thru this area. Speed seems to have no impact when jogging this area. This would be the lower end of my z travel. Not to be confused with a resonance issue. If I give it some extra lube, it will quiet down a little and then back at it. Jogging above that area is quiet and as expected.
While I didn't build this unit, I believe it to be a acme 1/2-10 lead screw with a round flange mounted AB delrin nut. Length of lead screw is about 12".
Z-axis plate & gantry is HPDE and holds a Bosch Colt router
So what's at fault? The nut or the screw or both?
** Update **
I should have looked closer, not a newbie, but should have looked closer at the hardware. The nut is a plain non-antibacklash delrin nut