My steam-wagon's ancestors were built in Bourton, near Gillingham. The North Dorset one.
I asked a friend from Sherborne, not ever so far from there, if Gillingham or Jillingham.
"Gillingham – hard G", he replied. "Soft G for the Kent one. Easy to remember – we're 'ard in Dorset!"
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As for the machine components, I have heard them pronounced either way and we still understand each other. The Gib Adjusters though are designed so that on old, rather worn machines they lead to "other" uses of the English language!
Once listening to two friends Up North arguing over whether the town COLNE is "Cone" or "Coln", eventually I said, "If you two Lancashire Lasses can't agree on how to pronounce your own town names, what hope for a Southerner like me of getting them right?"