Origin of saying 'hold this 'bout an hour'

My brother used to say that to his younger sibling when I’d be looking over his shoulder as he worked on a car, or whatever. He’d hand me something, and say, “Hold this 'bout an hour.”

I said it to my grandson today while helping him get his sneakers on. I untied and loosened the strings, and handed him one, “hold this 'bout an hour”. He giggled, and a lady who was passing by said, “My Dad used to say that to me, too. Wonder where it came from?”

Partial answer: “an hour” is an expression meaning “the right amount of time”.
its a very old literary short cut … of course the amount of time is unknown, variable…

Eg Shakespeare said “hour” when he didn’t mean anything like “exactly 3600 seconds”.
"Life’s but a walking shadow, a poor player,
That struts and frets his hour upon the stage,
And then is heard no more. It is a tale
Told by an idiot, full of sound and fury,
Signifying nothing.”
― William Shakespeare, Macbeth

Have you heard anyone else use the expression?

Western Pennsylvania, never heard the expression until today.

Ohio, SoCal, New England, and a Linguist–never heard it.

I think mechanic’s argot is fascinating. I wrote a paper about it in college after spending a summer as a mechanic helper/gopher/truck washer.

One old hand, working for me years later, had a favorite line he would use when trying to line up bolt holes or somesuch…“Hand me a pencil so I can draw this together”.

And, of course, the common one about needing to put a ‘little hair around it’ to get things to line up properly.

or, the farmer with the magneto-powered spark plug wire who would disconnect it from the distributor, and have a youngster ‘hold this for me’ while he cranked the engine over. No one ever gets knocked on their rear more than once with that one. You remember.

Or, they’d get you to stick your head over the engine to watch for a ‘leak’, then blow the horn…

One guy, who serviced our tractors and service trucks, always, the last thing he did before taking the keys back to the key-board, would be to turn the radio up to the highest volume on a top-40 station.