I'm trying to join 1 x 4 poplar with the jig. I'm using clamps in my shop. I drill 2 3/4 holes in the end piece and everytime the end piece moves about 1/16th toward the end of the face piece when I itghten. Any thoughts would be greatly appreciated.
Clamp it, then clamp it tighter.
I'm serious, I've had the same exact problem where it moves just a tiny bit. I use the right angle clamp and sometimes a couple other clamps to hold it fast where it won't move. After you get the first screw in, you should be okay, but the first one will move if not clamped tight.