Subject: Re: Q: How are steel bottles made?

From: [email-masked] (Dave)
Date: Wed, 26 Jun 1996 23:34:51 GMT

[email-masked] (Tim Nye) wrote:

>In article <[email-masked]> [email-masked] (Dave) writes:

>>Something I have often wondered, is how such things as oxygen
>>cylinders are made? I understand they can't simply be cast: they have
>>to be forged. But how to forge a hollow object with such a small neck?
>>They don't seem to be made in 2 halves & welded up, either.

>There are two stages.  First is 'backwards extrusion'.  A short cylindrical 
>chunk or red hot steel is placed in the bottom of a die which has a 
>cylindrical cavity the same OD as the finished bottle.

>Then a long, cylindrical punch with the same diameter as the ID comes down 
>into the work.  As it decends, the only place for the hot steel to go is up 
>through the gap between the punch and die, and you end up with a tall cup.

>For the second stage, the top of the bottle is heated red hot again, and a 
>machine called a 'swager' which has opposing hammers pounds the sides closed 
>to form the neck of the bottle.  The hammers are shaped to provide the nice 
>contours, and they rotate around the bottle as the process continues.

>There, confused yet? ;-)

>Tim

 Many thanks, Tim. I admit to amazement that the hammering process
(done only from the outside) can give the accurate form it does.
Methinks I won't try this at home...

 Thanks also to everyone else who responded.

--  Dave Brooks <http://www.iinet.net.au/~daveb>
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From: [email-masked] (Steve Rayner)
Date: Tue, 25 Jun 1996 09:33:22 GMT

According to my sources, the modern ones are spun.  During WW2 a lot of 
military tanks were coiled & welded at the same time.  The latter are not 
considered safe for re use.

In a previous article, [email-masked] (Dave) says:

>Please, someone enlighten me :)
>

-- 
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     MY SECRET IS OIL OF HARLEY DAVIDSON !      Steve Rayner
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