[BITList] down the hole

[HUGH]

Frank/Colin,

Stud couplings, etc, for small bore high pressure applications came in taper and parallel thread forms.  The former were prone to damage by those with access to long spanners who believed they had to be screwed up what looked like a facing.  It was a long learning curve on the drillships for some, but eventually they realised the seal came from the thread itself.  I have seen taper threads on the handles of brushes and mops, but they are a mere convenience.  They allow the threads to be hit or miss, so cheaper to make and easier to secure the handle.

Hugh.
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