Here's a typical turntable bearing, as fitted to our long-suffering Telefunken S 600 test rig. It's not the best of its kind by far, but neither is it the worst. The stainless steel shaft is rotating in bronze bushings, and a thrust plate (held with a circlip) bears the weight of the platter. The bearing housing is a nice oversized casting, somewhat compensating for a thin shaft.
To measure vertical acceleration, we've attached the accelerometer to a thrust plate. For horizontal axis, the similar Endevco Picomin 22
accelerometer is glued to the side of bearing body with cyanoacrylate.