An interesting thing happened this morning in the shop. The straight cutting guide I made yesterday for my Skilsaw didn’t cut straight. I trimmed one edge of my plywood top blank and when I laid a straightedge against the cut surface it would rock about 1/32”. Investigating, I found that my edge guide had a slight bow in it, about 1/64-1/32” in a 48” span. I assumed I had erred in its construction, normally a valid assumption, and set about to make another one. I had a piece of plywood about the right size and the edges both checked straight with my straightedge (an aluminum T-square that’s part of my Exac-T-Guide). I cut a new piece of hardboard and proceeded to glue and screw the two pieces together. Checking again with the straightedge I found that the plywood now had a bow in it of about the same magnitude as the one from yesterday. I removed all but two of the screws, leaving the two nearest the ends, and checked again – the glue had not not set up so the wood was free to move. The plywood checked straight again. Apparently when I drive screws I do it cockeyed so I’m going to let this one dry over the weekend while I go out of town. Fortunately I made the top blank big enough to allow for this kind of thing so I can still trim it to final size and don’t have to start over.