The 1×6 had six dowels in it and i pushed it together without glue and it is still together and that was 12 years ago. It would not come apart. I would have to have broken the wood to get it apart and that’s when I realized I had a problem. I did some research after that and discovered that a 9.7mm drill ...But as we went on through the years, what we found is the dowel sizes vary from company to company. You know, they give you all sorts of excuses that they can only go 5 thou, plus or minus 5 thou which is of course 10 thou and that can be problematic so Mike and I started looking at it again and did some research and thought that possibly the 9.6 might have been better rather than the 9.7 because it was more of a median size.