It wasn't an ordinary watch, but a pretend talking two-way radio wristwatch - as worn by the ace detective Dick Tracy, a popular American comic strip hero, greatly admired by kids on both sides of the Atlantic.
Of course, it was inevitable that I would catch the eye of Mr Ruffett while amusing myself talking to an imaginary watch.
Making a sudden beeline to my woodworking bench, his steel ruler raised, his beady eye homed in on my balsawood creation.
"What have we here?" he chortled aloud, holding my arm up to the class.
"It's a replica talking watch," I squeaked by way of explanation, adding: "A Dick Tracy two-way radio watch."
I was then frog-marched out to the front of the class, my arm still held aloft, where Mr Ruffett addressed the assembly.
"Forgive me, children, for wasting your time on elementary carpentry exercises, when we have a genius among us who's constructed a talking watch.
"Pray silence everybody, while Professor Broomstick kindly gives us an active demonstration of his amazing technology.
"Needless to say, if we don't hear any response from his creation, I think a small whack with my ruler might be appropriate."
I was then forced to repeatedly yell, "Calling all cars!" This was followed by a sharp rap across the knuckles, as my request was greeted with silence.
Thus ended my enthusiasm for imaginary Dick Tracy talking watches - that is, until today, when I rang the caregiver on an Apple Watch and she responded with a short grocery list.
Shame it has all come 70 years too late to placate my woodwork teacher.