Subject: Re: twisting tube

From: BILL PATE <[email-masked]>
Date: Thu, 29 Feb 1996 16:01:48 -0400 (EDT)

>I have been trying to twist some square tubing but it keeps collapsing.
>The tube is 1" square with a wall thickness of about 1/16". I want to end

Slide a piece of 3/4" round inside to keep the space open.

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From: [email-masked] (Bradley Sanders)
Date: Thu, 29 Feb 1996 17:47:00 -0500

>Slide a piece of 3/4" round inside to keep the space open.
Also, if you weld a washer with a 3/4" diameter hole in it to both ends, it 
gives you something to get the visegrips on, and you can give it a real 
controlled twist.

Bradley Sanders

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From: Mike Linn <[email-masked]>
Date: Thu, 29 Feb 96 18:06 EST

>> up with a 20" piece with about a 7" one revolution twist.
>>                                                         Thanks for any help.
>>                                                           Bob Schade

        As mentioned before, a piece of round stock inside the square will
keep it from collapsing. the smaller the round the deeper the grooves in the
twist... to a point then it'll collapse. 3/4" to maybe 5/8th" will probably
get you where you want. 

        Another tip to pipe/tube forging is to put a piece of duct tape
across the "handle" end of the tube. It keeps fire from coming up thru the
pipe and getting the handle hot and when cooled in the slack tub it keeps
the steam off the hands and face. 

        I discovered that if you've twisted the tube down tight against the
stock, if you CAREFULLY and slowly, pointing the open pipe end away from you
or others, pour a little water down the pipe the inner round stock will cool
and contract a little. enough to get the stock out.

mike
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               Michael Linn 
            Artisian Blacksmith
              AFC Web Master
 http://www.the-matrix.com/afc/index.html
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Smile, it makes people wonder what you've been up to.

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From: [email-masked]
Date: Sun, 3 Mar 1996 00:57:49 -0500

i did a little experimenting with twisting tube stock.
i found that if i put a piece of something else into the tube  then it
doesn't collapse all the way.  it only collaspes until it hits the inner
material.  this can give some really deep twist lines if it is a small piece
inside.  if the inner sleeve is just barely smaller than the nmain stock then
the twist cuts are fairly mild.  you also get different results if the inner
piece is round vs square vs hollow .

the only potential problem is the inner piece is permanently stuck..  if  you
can leave the inner piece in and it wont affect the work then fine.
   otherwise  i dont know.

scott sweebe

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From: [email-masked] (Bradley Sanders)
Date: Sun, 3 Mar 1996 10:20:31 -0500

>can leave the inner piece in and it wont affect the work then fine.

Hi,

     When twisting some square brass 3/4" tubing in the same method, I used 
an olive oil wipe on the inside bar. Olive oil has been used for centuries 
by goldsmiths as an ingot lubricant and release, because it is the only oil 
which doesn't break down under the heat required to melt gold.

     Also, try welding or soldering washers with a hole the diameter of the 
inside piece to the tubing at both ends... it tends to give you a good 
handle and to reinforce the ends of the tubing so it doesn't collapse and 
tighten itself on the inside piece.

                                        Bradley Sanders
                                        Sanders Museum Services