>
>However, I studied it a bit more closely this time and it appears to me
>that some of the drillings have almost started to break through to the
>inner surface - am I imagining it, or are there slight bumps on the visible
>part on the inside? If so, this is probably bad news ....
>
Not true. The marks you see on the inside are merely heat marks as a result
of the drilling. I ended up blunting two brand new 3/16 drill bits on the
stainless steel and towards the end I think the piece was getting quite
warm. Making all of those dimples really takes it out of the drill bit.
Doing a blind finger test on the inside of the tube produces not detectable
bumps.
>Any drilling like this needs to be done to a carefully set depth stop using
>a bench drill, _not_ a hand-held one, with the workpiece supported in a
>precisely repeatable way for each hole location.
Which is the technique that I used and documented on the site.
Tony
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