Working into space constraints, I really need a 1 inch hole, going over by 84 mils will put me into breaking sidewall territory, so I grabbed the 0.8835 "1/2" incher with the intent of making up the difference with file by hand. To its credit, it did seem to make a bit more progress before failure.
There are a lot of ways to botch a screw, and I've sheared my share of hardware via the mechanical force of the hardware itself; I do not recall seeing something quite this bad.
A little internet sleuthing (admittedly done BEFORE I purchased the tool, so you're all encouraged to laugh heartily AT me) indicates a lot of failure with the small stud, but apparently there's a newer revision that addresses the problem. Hopefully mine is first rev, this level of failure indicates process issue with me.
If you're bored and want to read more about this sort of thing, look up "cast iron railroad bridges".
I've given the stud a bit of scrutiny, and cannot find evidence of material having fractured out of the screw. Thread count matches, and I can see where faces would line up. However, the metal is now highly deformed and the gap will not close when lined up, as if it was under heavy preload prior to failure and relaxed into a state that puts a wide void where thread should be.
It's almost as if it's laughing at me.
The panel is getting nicely chewed up at this point.
Side by side, a comparison of losers. Really though, it's pull stud failure on both accounts, so instead of fussing about with further stupidity I'm thinking of visiting my local reputable hardware supplier and seeing what I can get in the way of threaded stock that can support this sort of load.
In the mean time, for this one, I just drilled it out as high as I can go with a drill (0.875") and made the rest up with a hand file, as evidenced by the bought of scraping situated inboard of the abnormally large pilot lamp assembly.
Now that the front panel can support a mock up, I'm free to position the iron for plunging the mounting holes and then moving on to tube socket & various. Thankfully, I'm substituting a 6BQ5 for the 6K6, and I can get away with making a hole to accept 9 pin miniature with the drill press. Otherwise, I'd probably be a bit irate about this experience.
Also, FWIW, my snap edge is the one pictured on the left, the uglier cut to right being one conducted in field with a circular saw (by others). Thought it crucial to defend my work since that will all be buried in woodwork anyway. HAH