[TowerTalk] Sweding

[Jim Lux]

Roger (K8RI) wrote:
> 
>> Looking for ideas on sweding, have  hyd 200 ton press. Like to swed 2 inch 
>> to 1/2 inch Al tube.
>>
> 
> I have a feeling you meant swaging and not sweding which has nothing to do 
> with reducing tube diameter.<:-)) (seems like that used to be spelled 
> swedging?) at any rate from 2" all the way down to 1/2" is more than is 
> usually done due to a number of factors such as hardening, wall thickening, 
> and a wrinkle free transition. OTOH, it's done in steps of maybe 1/8" at the 
> larger diameter and progressivlely smaller steps as the diameter gets 
> smaller (and the wall gets thicker and harder)
> 

There's also a somewhat entertaining method to get very large reductions 
called magneforming.  You put a coil around the work piece, and 
discharge a big capacitor through it.   The magnetic field cause the 
workpiece to shrink, and going from 1" copper pipe down to 1/4" isn't 
really a challenge, nor is ripping a beer can in half, nor is shrinking 
a quarter down to where it is thicker than it is in diameter.

Commercially it's used for such things as shrinking the can onto the 
base for spin on oil filters, removing dents from airplane wings, etc.


15-30 uF at 10-20 kV, with a work coil of 10 turns of AWG 10 wire 
closewound on a 1.5" form works pretty well.  The work coil is 
sacrificial, and do the operation behind something that will contain the 
shrapnel. I use concrete bricks. Others use plate steel. 3/4" plywood is 
not sufficient.


google "hickman quarter shrinker" for a site which explains it all.