Theres an explaination video that was shot... I'm putting  up the shop photos from tonight up for now.

 

Everything is cemented into place. Extra cements it poured in to the wall to "lumpy it up" and make it tacky for the hard plaastic liner

I'm guessing that the ABS variety of pipe I chose (for price cheap) would scratch and file away by the hard grit pretty quickly, so a hard liner is in order.  I priced out liquid truck bed liner, yikes $$$$$$

The hardest, thinnest material I could find around the house was a god-awful-ugly plastic placemat we had during the messy high-chair days.

Cut to fit inside the barrel and short enough to fit below the two flanges (one noted in red). I let the edges overlap and didn't worry about a perfect edge to edge meet around the inner perimeter, because....

...we need a tumbling bar! I'm imagining the rocks and grit just sliding down the slide of the rotating barrel versus a nice tumbling. This is a 3/8" scrap of plastic I yanked out of a window casing but I was ready to use any abs-based plastic objects to glue to the walls (Legos etc.). Back to my preface - the bar was slathered with toxic pipe glue and glues over the liner seam

Shes running with a full load! I was bummed when I saw a slow leak from the threaded flange. I also noticed that the barrel scuffed up in about an hour and barely noticeable slips were occurring every few seconds.  Its probably but a major problem but I really wanted this thing to last so two improvents are required: 1) Teflon tape 2) Wrap the barrel in something grippy - gonna try rubber bands.

Works pretty well but the ugly rubber bands are killing me. Here - the o rings makes me happy.