scrap 2x4's sitting around, so decided to see if I could make them. I had My Vet chop them to 8 inch pieces.
Then grabbed a drill with a 1/2 inch bit. Put some tape on the end of the bit to keep me from drilling too deep, and drilled my holes. Went in the house to test it with a marker, and my holes were just a bit too small.
So I tried a 9/16 inch bit, which made the holes to big to snuggly hold the lid. Now what?
Initially, when the hole was too small My Vet recommended just wiggling the 1/2 inch bit to make a slightly larger hole. (I of course, insisted on using the 9/16.) So I did what I should have done in the first place, and wiggled the bit while it spun, making a slightly larger hole. Those holes worked like a charm! It took a bit of finagling to get the lid in, but once it was there it wasn't going anywhere.
I hit them with a sand block to remove any possible splinters, and walla!
We made 5 in all, 1 for home and 4 for school. I can't wait to test them at school this week!