Back in the time when the early plastic variable speed Dremel tools were available, I bought one, with the associated drill press, for drilling pcbs. Using mostly carbide bits and some HSS bits, several thousand holes were drilled with no problems. Even though a few bits broke, the tools barely had any detectable shaft play until...
Fast forward to a few years ago, and for the first time, that Dremel was used to do some polishing, light grinding, and other operations that applied more radial force than axial. Despite regularly lubricating the bearings, side play in a bit mounted in the chuck became noticeable and rendered it unusable for precision drilling.
A new Dremel tool was bought but it did not fit the old drill press so a new drill press was bought. The new combination lacks the rigidity and even the admittedly poor tolerances of the old rig to the point it's useless for drilling pcbs. Now days, modeling tolerances require better tolerances that that required for my pcbs.
In the interim, the old Dremel has been rebuilt with new bearings, brushes, etc and is again good enough for drilling.
I currently have more than one Dremel tool. Those that are used for drilling are not used for polishing or grinding et al.