I spent a little more time on it tonight, mostly straightening up the hole using the carbide burr, and then ran the tap through it. I got in 18mm, (which is better than I did on Prom Night) but the threaded portion of the original studs is 25mm. Now I must decide if I rest on my laurels and stop here, or try to get another 7-8mm and risk buggering up what threads I have left.
