Anyone know how to keep cut square when hack sawing

[Enoch]

Mark the metal both across and down, use a square to make sure both lines are at exactly 90 degrees to the work piece, make sure the lines are quite thin but easily visible. Use smooth deliberate strokes on the saw, take your time. Focus your attention on the two lines. The saw will be pointing down at the front approx 15-20 degrees. Always use a good quality blade - I like the bimetallic ones. Key thing is to not be in too much of a hurry, a good blade will cut quite quickly. Keep your body still, with a bit of practice it becomes a lot easier. The other way is to get somebody else to do it
All the best,
Enoch