Install the blade on a hacksaw so the teeth face forward. The saws are designed so the blade will cut when it’s pushed (the forward stroke) rather than when pulled. Some blades have an arrow that shows the correct installation (the arrow points toward the handle). Install the blade so it’s tight in the saw and won’t bend. When you do a lot of cutting, the blade will heat up and expand, so be sure to tighten it if it starts to bend.