Glad you got it solved. Too bad the bolt stub didn't come out easily, but they never do for me either.

On 9/28/2020 at 7:30 PM, Captain Obvious said:

M6 x 1.0 is used extensively all over the car, and while I did not look up that bolt specifically, I believe that's what it is.

As for the official pilot drill size necessary, I'd have to look into that. There are rules for metric taps (that I never committed to memory), but it would be easier for me to instead just see what size drill bit fits snug into the threaded hole of a couple M6 x 1.0 hex nuts and just use that.

Edit - You made me look... My crib notes says I use a 3/16 (.1875) drill for my pilot when tapping M6 x 1.0. It's probably a little undersize according to the rules, but that's how I roll.

The basic rule for metric tap drill size is very simple. Tap drill equals thread size minus pitch, for M6x1.0 tap drill is 5.0mm (.1968"), closed imperial drill is #9, .1960". Here is a printable Starrett toolbox card with inch/metric tap drills and decimal equivalents that I have found very handy and a link on the Starrett website.

https://www.starrett.com/docs/educational/decimal-equivalent-card---bulletin-1317.pdf

 

Starrett-decimal-equivalent-card-imp-metric tap drill-bulletin-1317.pdf