LP12 inner platter dimension

Does anyone know the exact diameter of the LP12 inner platter?
Looks like 5 3/8 top step and 6 1/2 on the bottom step. I could only remove the outer platter and lay the tape on its edge. You can also contact Linn in Jacksonville Fl and they may have the exact mm. These measurements are in inches. Hope this helps.
I just measured the inside hole of the outer platter and it looks to be 5 3/8", so I think I'm pretty close on the first measurement.