[AT] List quiet!! Everyone OK, or just waterlogged??? --> Lug bolts, JD A

[szabelski at wildblue.net]

Another good example would be how they make spoked wooden wagon wheels. After all the pieces are put together they heat up the metal ring to expand it, then cool it off with buckets of water after it’s in place to shrink it back down (and before the whole thing burns up).

----- Original Message -----
From: Stephen Offiler <soffiler at gmail.com>
To: Antique Tractor Email Discussion Group <at at lists.antique-tractor.com>
Sent: Thu, 04 Jul 2019 07:02:28 -0400 (EDT)
Subject: Re: [AT] List quiet!! Everyone OK, or just waterlogged??? --> Lug bolts, JD A

Yep.  The washer example is a great way to explain how thermal expansion
works on holes.

SO


On Wed, Jul 3, 2019 at 3:31 PM <szabelski at wildblue.net> wrote:

> No. Thermal expansion is constant.
>
>  Consider a flat washer. If you heat it, it will expand on the outside and
> get larger because the molecules are separating due to the heat. The outer
> circumference is now bigger.
>
> Likewise, the inside expands due to the heat and the internal
> circumference becomes bigger by the same ratio.
>
> Think of what happens to the outer edge. The outer edge gets longer so the
> diameter becomes bigger because it remains circular. Now apply the same
> thought to the inner edge. It gets also gets longer, so again the diameter
> becomes bigger because it remains circular.
>
> The washer also gets thicker due to the heat.
>
> Have you ever seen someone replace the lower pulley on a Farmall Cub? You
> really have to put a lot of pulling force to get it off of the crankshaft.
> In order to get it back on, you have to heat the pulley to somewhere near
> 300 degrees and press it onto the crankshaft. That’s why the crankshaft is
> threaded on the end so you can use a 3/4 inch bolt and washers (or some
> other spacer) to press it on.You have to make sure both pulleys line up
> properly, so you need to get it right while the pulley is hot enough. When
> the pulley cools you can’t just tap it back and forth to line them up, it’s
> on there good.
>
> There are also cases where bearings have to be heated in order to get them
> onto a shaft.
>
> ----- Original Message ----
> From: Mike M <meulenms at gmx.com>
> To: Antique Tractor Email Discussion Group <at at lists.antique-tractor.com>
> Sent: Tue, 02 Jul 2019 12:29:37 -0400 (EDT)
> Subject: Re: [AT] List quiet!! Everyone OK, or just waterlogged??? --> Lug
> bolts, JD A
>
> Wouldn't heating the "hole" cause the steel to expand making it smaller?
>
> Just curious.
>
> Mike M
>
> On 7/1/2019 9:10 PM, szabelski at wildblue.net wrote:
> > When applying heat you want to heat the item the bolt in threaded into,
> not the bolt.
>
>
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