I have tried several models of flow through systems and continue to tinker to get the results I’m looking for. The idea is for the finished castings to fall through the grate at the bottom of the bin and the worms to work towards the top of the bin.
Materials: square metal tubing, plywood, braided cable, 1.5″ self tapping metal screws, small I beam we found for the base bar to mount winches, and 2 winches (one we salvaged and another from Tractor Supply @$20) for pulling each direction.
We welded a bar to slide along the bottom of the bin to agitate the castings through the grate. I have tried other versions without the cutting bar, and castings tend to get clumpy and stuck. Stay tuned for the big reveal when we add worms and a few finishing touches.
Texas Jumpers 
For the base of my bin I put loose flat bars in “upright” knife edge up bettween 1″ square tube spacers, you can then use a rake or pitch fork to scrape out the material from the bottom. None of my scraper design’s worked all got stuck. Simple is better.
Ian C
Great idea. That sounds like an excellent design.
Thanks for sharing.
Hey Ian–would you be willing to post/email me a picture of your arrangement? I’m considering a couple of different options for building my own, medium scale flow through system. Thank!
The only worm I would recommend for any in ground application is the Jumper.
Hi ~ Sure will take a look on my work PC if the “internal working” pics are still there……..Send me your email to : home@zim.co.zw rgds Ian
Just posted two bin pics to my face book page:-
Vermiculture ~ Southern Africa
See more pics & text detail on : https://www.facebook.com/groups/1509031789381996/
In hindsight I would make the sides flat & the top a couple of inches narrower to aid gravity.
I was using roofing sheets I had to hand. The “LOOSE” flat bars at the base, work very well, have no intention at this stage in changing the base concept. . . . Ian