Spindel clearance ?

Hi
I have a Cylindrical Grinding machine TOS HOSTIVAR, and I have a problem on OD grinding , problem is that during the grinding I have in feed grinding of wheel into my worpiece and make my workpiece oval
I don't know what is the problem I think my spindle clearance is too high and I measure it by dail andicator and pulling or pushing the spindle shat and I saw 0.4 mm radial clearance
Is the clearance high or ok?

My grinding method: 0.005mm depth of cut wth high feed rate movement.
Material stainless steel.

I am wait for your help.
Thanks