Are we talking about the first step, making the hour glass block?
Low is completely right, no-ones blocks are ever 100% perfect and, especially with HST's, I often make them just that lil bit bigger and square them down to the right size.
Usually Destructions for an HST are to cut squares
7/8ths of an inch bigger than the desired finished size ...
7/8th 's My arse!! Cut them an inch (or more) bigger and square down!
Ask as many questions as you like, we have all been there and done that .. even if its to ourselves in an empty room!!!
You should have heard me rave yesterday as I was trying to put a block together that simply wouldn't go!