Hello everyone,

Some months ago I've been drilling pin holes (6mm) with very tight accuracy.
The pins were just sliding into the holes smoothly.

But on the last job I've lost that tight size tolerance and now the drill holes are way looser than before.
Even with new drill bit (from the same brand).
Now I need to use 6.2mm pin in order to fit nicely in a hole drilled with 6mm twist drill.
It wasn't the case before when I was using 6mm pins for a holes drilled with 6mm drill and the fit was almost perfect.

I've tried drilling with a drill chuck holder and also with a TTS ER collet holder, the result was the same.
Not even close to the tolerances from few weeks ago.

Here is a link to some videos that I've made measuring the run out of the tools.
https://drive.google.com/folderview?...BkV4RzQDa6q3gm
Please let me know if you have any problems viewing the videos.
The scale on the indicator is in mm, 0.01mm

Could you please advice what would be the reason for loosing that accuracy.
What should I do to fix it.

Machine is Tormach PCNC 1100 and we're working mainly with steel and aluminum.

Thanks a lot!