Slic3r and/or printing anomaly

You might want to check your backlash on X and Y axis.  It looks like the "shadow" extends all the way to the edge of the part from the protrusion.  This indicates to me that the axis ended up in a different location when going in the opposite direction than turning the original corner.

I've printed out Ian's Belt Tension Gauge and finally found enough quarters but haven't used it yet.

The belt tension gauge is probably the most expensive print I've done.  Unless you want to go slumming it with washers but I like my printer accessories to have a little class.  Maybe I'll replace the quarters with some gold Sacagawea dollar coins just because.

If you record a short video, does it pick up the clanking sound you are talking about?

I tried to upload the (20 MB) movie here, but the site silently barfed.  Try looking at www.jonbondy.com/clanks.mov

I just tried printing something on that printer, and within a few minutes, there was a clanking noise and the print was off in the Y direction.  I checked the voltage on the Y  motor driver, and it was 0.515: I bumped it to 0.520, but that difference seems unlikely to be the problem.  I printed out Ian's belt tension gauge, but am not sure what the "right" tension is.

One of the guide rods seems to cause increases in resistance to movement when rotated in the "wrong" orientation.  I reoriented it, but see no way to keep the rod in the optimal orientation.

I tried to put the X and Y movements through their paces, using Repetier Host's Manual Controls, but I feel as if the movement is too slow.  My maximum speed in Slicer is 75 mm/s, or 4500 mm/min.  My setting in the RH configuration for Travel Feed Rate is 4800.  I would like to use the Manual mode to check things out, but in Manual mode all seems well.

I wonder if someone should create an X/Y torture test gCode file...

The back rod runs through bushings and the idler pulleys on the front are on bolts.  When you tighten the belts it adds friction to both of those places, making the axis harder to move.   The bushings and the front pulleys would be better off replaced with bearings so you can keep the belts tight and maintain smooth motion.  There is a tradeoff between loose enough to move, and tight enough to keep the x carriage stable.  I havent really figured out what the balance is, but I tend to keep the belts looser.   I have some bearings to try out, but there some other projects in line ahead of that one.   

I don't know a correct belt tension.  I usually seem to run it between 3 and 4 notches  visible on the guide between the belts.   Check it with the nozzle forward and with it back.   I've seen the tension differ between those positions.

Replacement rods from Solidoodle are $6 apiece, which seems reasonable.  But they want $18 to ship 2 of these, which seems absurd.

I went to  McMaster Carr, and all I could find in 8mm was hardened shafts for $12 apiece.  Not sure exactly what Solidoodle might be using.  Maybe one of you will know better than I