Brazing or hard soldering with suitable flux for the steel + cleaning.

Gluing with epoxy (that can take 200+ deg. C).

Forced assembly using a tight tolerance on the holes and a press.

Same as 3. but with a profiled pin driven in (the fluted part would be
nice for this).

I don't think that brass qualifies as sterilisable metal under all
circumstances. Please check this.

Peter

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