drill bit size

[Brent]

I have been using 7mm,8mm,10mm drill bits for the kits that I have been using. I noticed that some companies use letters instead numbers. Just wandering if anybody could tell me what the size "O" is

 

[Fred in NC]

Drill bit size chart here:

http://www.penturners.org/content/HUTDrills.pdf

8 mm drill is .3150" - Letter size O is .3160" or
.001" bigger than 8 mm.

 

[Brent]

Thanks Fred. I guess I should look on the home page more often