In article ,
Andy Burns wrote:
At some point in the next week or two, I'll want to drill and tap a
dozen holes into stainless steel tube, this is 2mm wall thickness, 42mm
diameter handrail, I'll have a 100-200mm offcut to practice on.

Now, we didn't do metalworking at school, so I'm lacking in the basics,
but a bit of searching seems to suggest ...

For M5 bolts, use a 4.2mm drill, assuming it's 0.8mm course pitch (need
to check) hopefully an 18V cordless drill/driver isn't going to struggle?

A 2mm wall thickness ain't going to give much of a thread for M5 bolts.
The usual way would be to weld in bosses to increase the thickness. As a
rule of thumb, you want about the same thread length as the diameter as a
minumum.

--
*If you can't see my mirrors, I'm doing my hair*

Dave Plowman London SW
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