finally ivanising..

[Falcon 269]

get a thin bit of wire like a paper clip and poke it down the hole to the bottom then mark or bend it when it enters the hole. put the drill back down as far as it goes and mark where it enters the hole. you can now compare the lengths to make sure you got to the bottom.



Unnecessary, really.  


The thickness of the metal you're drilling through is less than 1mm and the void beneath is not much larger.  You're either through or you're not.  It is quite obvious when the hole is enlarged. 


I would advise against messing around bending paper clips or similar in case you have the misfortune to break it off in the hole.  Then the fun would really start ...