Bike Chains and Derailleur Gears

After getting a tip from one of my friends about a bike shop in town that might be able to give me some free bike chain I stopped by to see what I could get donated.  I ended up getting 5 or 6 derailleur units and about $100 of free used bike chain.  The inspiration for using bike chain came from James Glanville and his project creating a similar 3D printer from common parts.  The derailleur units each contained 2 jockey wheels used to route the chain through them.  I took apart all of the derailleurs and removed the jockey wheels.  They just happened to have a 5/16" inner bore!  What are the chances?!  So I sandwiched one jockey wheel on each Z axis drive rod between two lock washers and a couple nuts.  I tried as hard as I could to make the jockey wheels slip on the drive rods but can't generate enough force to accomplish it so I think it will work find for this application.  I then used my new chain tool to splice the chains together in the appropriate lengths to connect all of the Z axis gears to the stepper motor driving it all.  I experimented with using one large chain that looped around the entire machine but had issues with tensioning and the chains derailing (ironic?).  The solution was to use one chain loop per two drive rods.  I tried using 4 different loops to complete the circle but I had issues with alignment.  When you complete the circle all of the gears need to be perfectly aligned.  I ended up always having one chain that was stretched far to tight and the other side had too much slack.  

Edit:  Here is a shot of what I am talking about.  You can see how the back chain has additional slack on one side and is stretched on the other.  I did eventually get the gears aligned to get rid of this problem, but the friction was still much higher and required a much larger motor torque to move the Z axis.

So in the end I settled on only 3 chain loops which still engaged all four rods, but avoided the tensioning problems I was having with 4 loops.  There might be eventual problems with the vertical supports bending or deforming as only the left side in the picture below is in compression while the other side is free to stretch and bend.  Either way I don't notice too much of this at the moment so hopefully it won't be an issue.  Just in case I am leaving the extra gears so I can always throw the fourth chain on if needed.  Here's a shot of the current drive train.  

The whole system turned rather freely by hand so I attached my motor driver that I had made before to the Z axis stepper and fired it up to test it out.  Moment of truth.....   it worked!  All four drive rods turned pushing the table up!  It worked beautifully for about 5 seconds and then completely died.  I later found that my power supply which was salvaged from a 1990's computer had died under the high current load (and probably lots of dust).  It was rated to supply more than double the current I was driving the motors at, but I guess age had gotten the better of it.  I ordered a new 500W ATX2 power supply from Newegg that can supply up to 18 Amps on the +12V rail.  I think that should cover any future current problems.