The first pair I used was very difficult to start screwing into the piece of wood. Being softwood it was also difficult to get them to start straight. After struggling with the first pair, I used a 1/2" tap to slightly widen the beginning of the 3-8" hole and the starting problem was solved. Care must be taken to keep the allen wrench straight and pressed into its socket as these sockets are quite soft and easily removed with a wrench.