I built my flow through based on the 55 gallon drum design. I had a large trash can had sitting around waiting to become a rain barrel but decided to make into a worm condo.
I marked and drilled 3/4 OD holes on either side. I used a tape measure and level to make sure they lined up to each other.
I used 1/2 ID conduit (3/4 OD)for the spacers. HD sells them in 10' lengths for $2. I wasn't until I drilled the holes that I realized I needed 11 two foot lengths of conduit. I could have saved $2 by only having to purchase 2 pieces of 10' conduit if I measured the spacing for 10 rods.
I wrapped the ends of the spacers with duct tape so that they would not slip out.
I opted to run the spacers east/west and have the opening on the south side to reduce the load over the opening. It will be a little more difficult scraping sided to side rather than back and forth. Here is a view from the inside.
Here is one looking at the opening. I didn't have a jigsaw so I used my Dremel tool with a cutting bit to make the opening.
It is loaded up with some newspaper ready for some finished compost, veggie scraps and a pound of worms. I will probably order the worms next week to give the 'condo' a breaking in period with the new furnishings.
Total cost was a little more than $6. | 
