My rotary tool had large wobbling at the tip of bits. Maybe I bought a cheap rubbish. I found the bottom of the hole that accepted the collet was flat. It should be cone to centralise the end of the bit.


So I made a cone from 5mm styrene rod and put it at the bottom of the collet hole.


I made this by turning the styrene rod on drill press with a chisel.


Pushed this cone into the hole.


Tighten the collet with the bit pushing. Then only very small wobbling observed.



inserted by FC2 system