Well, I'm pretty sure this isn't a standard tool in most DIY toolboxes. In fact, I've NEVER needed one until this Subaru engine. Now I live in a pretty small town, and in the "back" of it as well, so virtually every trip to the store takes about an hour's worth of driving and shopping, and most of the tools in town are over-priced because they can. I'm pretty sure I'll pick up a 14mm next time I'm in a reasonable place to do it, but since I wanted to get the job done right away....
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14mm from the bucket-o-bolts, matching nut, a minute with the welder. About 5 minutes total. Yes, yes, garbage welds. I have to do a bunch of test welding to get the settings right for anything pretty, and here I was only concerned with penetration, so power up FTW!!! Worked a charm.