Glad you asked! You might be sorry you did! I'm actually having problems using these dowels, and wouldn't mind some ideas. I'll try to make a long story short. I've enclosed a drawing and a photo. Many years ago I started to carve a large mushroom. For the top, I laminated eight 2 x 6 's (actually 1.75” x 5.5”) using hide glue which is an indoor glue. Recently I donated this carving to the local senior center for their outdoor garden, and with the weather, a large piece broke off the top. I'm sure more of the boards would have delaminated in time. I decided to reinforce it with dowels and exterior glue (Titebound III). I was afraid regular dowels would just displace the glue, so I wanted to use fluted dowels. Your 5” x 5/8” were the biggest fluted dowels I could find. The drawing shows my plan. Because of the drill bits I had available, I had trouble drilling 5/8” holes that deep. I had envisioned a nice snug fit, and that I would be tapping the glue embedded dowels in with a mallet. But when I tried fitting them, they were falling out loose. They measure about .615” at the widest point. I tried soaking some of them for a long time in water and that kind of put them over the 5/8” width. Still they were kind of loose, hardly making contact with the original boards. Also I'm not sure water logging them is such a good idea. It turns out, because of the depth I needed for the holes, I ended up making some pretty sloppy holes. So I'm sure that is also a factor. I was thinking of making a kind of paste by mixing glue and sawdust. I'd fill the grooves in the dowels with regular glue and coat the outside with this mixture of sawdust and glue as I'm pushing them in. So that's my story. As with many of my projects, things don't always go according to plan! Denny Kayser (978-256-0642) PS I couldn't attach my pdf drawing showing the dowels.