Originally Posted by
WizardOfBoz
I asked the question: 5/8 or 3/4 on a site for professional machinists I visit. Will report back if there's any clarification. In the mean-time... Use a number 7 drill! It's 5.105mm!
The topic has been discussed numerous times on Practical Machinist. Search the website ...
The two charts you referenced in a previous post list 5.00 mm and
#10 (4.91 mm) as the drill size for M6 x 1 threads.