Here is a great, portable solution for drilling straight using a hand drill
Drilling straight holes with a hand drill can be challenging, especially when using large bits. A drill press does this well, but it’s not a tool everyone has. And even with a drill press, working with a large piece can be very challenging.
A portable drill guide acts like a miniature drill press by guiding your drill for straight holes. A portable drill guide can be tough to find in home centers, but you can pick one up online.
To use it, you just place the drill bit into the chuck on the drill guide, and then attach your drill to the shaft on the chuck. Hold the drill guide in place to position the bit, and then drill.