Frank Krygowski wrote:

If you're drilling and tapping in (say) rear
dropouts, normal practices should be fine.
But if you're planning on drilling and
tapping frame tubes, you probably wont' have
sufficient wall thickness in the tubes.

It's usually considered proper to give tapped
holes a thread depth at least 1.5 times the
screw diameter. So for a 5mm screw, you'd
want 7.5mm of thickness. Sometimes a little
less can be OK. But your frame tube walls are
probably less than 1mm thickness.
That's not enough.

The stays that hold the chainguard, both from
the front and under, are very thin, probably
around 1mm. Still it is enough for a couple of
Torx flat-headed M5 screws to hold it (1 from
under, 2 front, the one at the rear is usually
bolted tho with a nut on the other side).

The down stay is also fastened in the same way
to the frame. (I don't know how the front one
is attached because you typically don't remove
it. But I'll check it out.)

With Loctite I suppose it'd be even more
strength to it?

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