A trick to get your screw holes to line up, works if you have a drill press and if you know where you want the hole to enter and exit on both the top and bottom of the stock. It’s especially useful if you’re working from a funny shaped blank that may not be exactly squared up.
Take a sheet of plywood and cut a square about a foot on either side, and put a 16-penny framing nail from the bottom up. Put this on the table of your drill press, Position you board with nail in exactly the right place, so that the drillbit point lands exactly on top of the nail point, and use at least 2C clamps to clamp the plywood in place to the table. Now sit your stock so the point of the nail sits exactly on the bottom of where you want the hole to exit. Then start the top of the hole with the drill bit where you’ve marked the hole from that end and start drilling, but stop about halfway. Then flip it over locate the nail into the start hole so it sits exactly in the center, then start drilling from the Mark on the other end. This ensures that the two holes meet exactly in the center.
This sounds good but I'm struggling to wrap my head around the angles if your piece isn't square.
How do you ensure the angle is right and that the 2 holes line up without having a dog leg in the middle?