When I first read this puzzle (years ago) the answer mentioned a cooper heating a metal ring to make it easier to get it on a barrel. That's why I chose such an unusual sized torus; as a red herring. (And in the hope that some might think the tiny hole would be 'overwhelmed' by the the torus in some way.)

Just like that!

[quote=wblipp;195798]...Blacksmiths know better - a really tight fit is sometimes made by putting the "plug" on dry ice to make it smaller and heating the hole (OK, so the metal around the hole for you [B]pedants[/B]) to make it larger. Tongs a sledge hammer finish the task.[/quote]

[I]"A [B]pedant[/B] is a person who is overly concerned with formalism and precision, or who makes a show of his learning."

[/I]Hmm, Oh well.

I'll have to repeat the experiment, if I can repair my calipers. I dropped them and the needle came off the dial. They're quite old.

[QUOTE=storm5510;195816]Um... It was an oven. I'll get it started. Once it reaches 500°F, I'll saturate it for three hours, minimum.[/QUOTE]

I meant what I wrote. If you take it from 30 F to 500 F, you'd expect about 0.011; from 70 F to 500 F, more like 0.010.

[quote=CRGreathouse;195873]I meant what I wrote. If you take it from 30 F to 500 F, you'd expect about 0.011; from 70 F to 500 F, more like 0.010.[/quote]

We posted at the same time. How about starting around 0°F. My freezer usually runs in that range. Measure at zero and then again at 500?

[QUOTE=storm5510;195874]We posted at the same time. How about starting around 0°F. My freezer usually runs in that range. Measure at zero and then again at 500?[/QUOTE]

It would be about the same -- 0.011, maybe 0.012. I think 0.010 is the best you could reasonably hope to measure with the difficulties of taking it out of the {freezer|oven} and having it come toward room temperature.

I managed to repair my calipers. I slightly heated the needle hub to make it hold onto the dial post. As I said, it's an old mechanical type.

I don't know how accurately I can measure this object. It is not machine-grade by any means. There is not a common dimension between any two sides. I suspect it came from a piece of farm machinery.

I will pick a pair of sides and mark them and see what I can come up with.

[QUOTE=storm5510;195912]I managed to repair my calipers. I slightly heated the needle hub to make it hold onto the dial post. As I said, it's an old mechanical type.

I don't know how accurately I can measure this object. It is not machine-grade by any means. There is not a common dimension between any two sides. I suspect it came from a piece of farm machinery.

I will pick a pair of sides and mark them and see what I can come up with.[/QUOTE]If your object is not very regularly shaped, you must make sure you take your second measure in exactly the same place as the first one. You will also have another problem measuring the object with your calliper : it is meant to be used at a "normal" temperature, once the object is heated it will transfer heat to the calliper and the measure will not be accurate.

The question is why measure ? Instead of thinking of what happens to a disk, think of a ring of thin wire. It will lengthen when heated and the hole will grow.

Jacob

[QUOTE=S485122;195922]The question is why measure ?[/QUOTE]

Why not? I expect the hole will grow, but I'd like to see how closely the expansion matches the prediction. Also, measuring the outside as well as the inside gives a check on the measurement.

[quote=S485122;195922]...You will also have another problem measuring the object with your calliper : it is meant to be used at a "normal" temperature, once the object is heated it will transfer heat to the calliper and the measure will not be accurate...[/quote]

I considered this, and the reason I will do the measurements as rapidly as I can to avoid as much temperature transfer as possible.

I marked a spot on the bottom side to measure at because of the dimensional irregularities.

I have the cold measurements complete. The freezer cycles from 0°F up to 9°F. I have the nut sitting out and it is almost snow white from frozen condensation. I will do the hot portion later today or this evening.