Cynthia Eid
ceid@cynthiaeid.com

Ok , this is a good news/bad news kind of thing.  The good news is that they worked!

I put scraps of the silver I'd cut for the 3" disc between the bolts on the MDS to avoid any flexion of the plates.  I also used the torque wrench (25 inch pounds) to try to make the first pressing as evenly drawn as possible.  This was quite successful.  The metal varied between 1.0 and .95 mm thick. (And the top edge remained smoother throughout the deep draw process)

For the second, third, and fourth draws, I used 1/8" o-rings--one at the bottom, and two at the top, everything well larded.  In each draw, the o-rings squirted out of the top nicely.

Here's the bad news:  
During the fifth draw (from 1" diameter to 3/4") the snake/egg syndrome struck (see Lee's post).   There was a huge noise, which I could not figure out for a while.  It turned out that the top had torn off, with the 0-rings mostly stuck in the top, but partly still in the bottom/drawn section.

The good news is that after I got everything apart, and sawed off the snake/egg/torn section, I found that the thickness was very consistent---varied only from 1.02mm to 1.05mm.  Wow!  We're on to something here!

After a quick trip to the hardware store because I'd forgotten that I needed 1/16" o-rings for the final draw (3/4" to 5/8") I tried drawing the 1 1/2" length of 3/4' diameter tube that I still had.  I put one ring half way down, and one at the top, hoping that might work better than the one-at-the-bottom one-at-the-top system.  No such luck.  The o-rings slid well for 1 1/4", and then the snake/egg syndrome struck again.

The good news:  after trimming off the snake/egg bulgy section, the wall thickness variation was only from 1.04 to 1.08mm.  (I love that digital caliper I bought when Lee, Jim, Anne, Uwe, and I hit the used tool store near Bonny Doon last year!)

My plan for my next adventure in the studio (hopefully tomorrow afternoon, but we'll see--I'm coming down with a cold or something):

1. Measure the wall-thickness variations when I don't use a torque wrench for comparison.
2.  Try drawing using 0-rings for the 2nd, 3rd, and 4th draws, and wax wire or strips for the 5th and 6th draws.  I think this will work.  I'll let you know!
Cindy
www.cynthiaeid.com