Badly behaving brass

On Mar 4, 7:14 am, "dadiOH" <[email protected]> wrote:
> I used to have a wooden sail boat that was made in the 30s. There
> were several forged iron rings on various spars and I was told that
> the way to get them on was to make the ring with a slightly smaller
> inside dimension than the OD of the spar at th desird ring position,
> grease the spar, heat the ring, position the ring on the spar and then
> toss a bucket of water on it. The ring shrinks and is forever at the
> correct place.
>
> Well, lately I have been making myself a new cane. The shaft is
> hickory, head mahogany. The shaft is reduced into a shouldered
> spindle where it goes into the head. I wanted a transitional
> pretty-pretty between the two different woods and decided to use
> brass. A piece of 3/4" brass pipe is just the right outside diameter
> but the inside diameter was a bit too small to get over the spindle so
> I decided to try the heat & quench method ala spar rings.
>
> I cut off a 5/8" wide piece of the pipe to use as my ferrule and
> heated it up to see if it would expand enough to get over my spindle.
> The dang thing didn't get any bigger; in fact, the ID *decreased*.
> Huh? I thought about that for a moment and decided that the wall of
> the brass ring must be expanding both outward and inward and therefore
> the ID was decreasing, OD increasing.
>
> But then I started thinking about what would happen if I cut the brass
> ring and flattened it out into a strip. That strip would be 5/8"
> wide, about 1/8" thick and 3+" long. Heat that and each dimension
> should increase but the length would increase most, right? Bend that
> now elongated piece of brass back into a ring and the ID should be
> bigger, right? So why did my piece of pipe decrease in ID when I
> heated it?

Are you sure it wasn't distorting? Maybe the overall interior 'area'
was increasing in size while a particular diameter was decreasing?

R

On Mar 4, 7:14=A0am, "dadiOH" <[email protected]> wrote:
> I used to have a wooden sail boat that was made in the 30s. =A0There
> were several forged iron rings on various spars and I was told that
> the way to get them on was to make the ring with a slightly smaller
> inside dimension than the OD of the spar at th desird ring position,
> grease the spar, heat the ring, position the ring on the spar and then
> toss a bucket of water on it. =A0The ring shrinks and is forever at the
> correct place.
>
> Well, lately I have been making myself a new cane. =A0The shaft is
> hickory, head mahogany. =A0The shaft is reduced into a shouldered
> spindle where it goes into the head. =A0I wanted a transitional
> pretty-pretty between the two different woods and decided to use
> brass. =A0A piece of 3/4" brass pipe is just the right outside diameter
> but the inside diameter was a bit too small to get over the spindle so
> I decided to try the heat & quench method ala spar rings.
>
> I cut off a 5/8" wide piece of the pipe to use as my ferrule and
> heated it up to see if it would expand enough to get over my spindle.
> The dang thing didn't get any bigger; in fact, the ID *decreased*.
> Huh? =A0I thought about that for a moment and decided that the wall of
> the brass ring must be expanding both outward and inward and therefore
> the ID was decreasing, OD increasing.
>
> But then I started thinking about what would happen if I cut the brass
> ring and flattened it out into a strip. =A0That strip would be 5/8"
> wide, about 1/8" thick and 3+" long. =A0Heat that and each dimension
> should increase but the length would increase most, right? =A0Bend that
> now elongated piece of brass back into a ring and the ID should be
> bigger, right? =A0So why did my piece of pipe decrease in ID when I
> heated it?
>
> --
>
> dadiOH
> ____________________________
>
> dadiOH's dandies v3.06...
> ...a help file of info about MP3s, recording from
> LP/cassette and tips & tricks on this and that.
> Get it athttp://mysite.verizon.net/xico

It didn't.

As the ring expands with heat, so will the hole. Not by much, though.

The coefficient of expansion of brass is .00001 per degree
Fahrenheit. That's almost twice that of steel or wrought iron.
Still, heating your ring by 400 degrees would expand it only .003" in
diameter. Not much, is it? Not much by woodworking standards anyway.

You'd be better off heating the wood to shrink it by drying.

I'd just press it on, though.

John Martin