How to use a Hacksaw

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====== How to use a Hacksaw ======

**Choose the Right TPI (Teeth Per Inch)**
  14 TPI (Coarse): For soft metals like aluminium, brass, copper, and thick plastics.
  18 TPI (Medium): For general mild steel, angle iron, and electrical conduit.
  24 to 32 TPI (Fine): For hard metals like tool steel, cast iron, thin-walled tubing, and sheet metal.
  
  The Golden Rule: You must have at least 3 teeth touching the metal at all times

**Install the Blade Correctly**
  Direction: The teeth must face forward (away from the handle). When you push the saw, it should cut; when you pull it back, it should glide. (Check the arrow printed on the blade!).
  Tension: Tighten the wingnut until the blade makes a high-pitched "ping" when you pluck it.
  
**Secure Your Workpiece**
  Clamp the metal firmly in a bench vice.
  Cut close to the vice: Keep the cut line within 1 inch (2.5 cm) of the vice jaws. Clamp it tight!
  
**Mark Your Cut Line**
  Use a scriber or a sharp awl to scratch a line across the metal. (Pencil marks rub off on metal).
  Use a try square to ensure the line is perfectly perpendicular if you need a straight cut.
  Put a centre-punch mark right on the line to help the blade "bite" when you start.
  
**The Cutting Technique (The "Push" is the Cut)**
  Hacksaws only cut on the forward push stroke.
  Starting the cut: Place your thumb against the side of the blade to guide it. Use very short, gentle strokes pulling the saw backwards a few times to create a shallow groove (a "kerf"). Once the    groove is started, move your thumb.
  The Stroke: Use long, full strokes—using the entire length of the blade. This clears swarf (metal shavings) from the teeth.
  Pressure: Apply firm, heavy pressure ON THE FORWARD PUSH ONLY. On the backward pull, lighten the pressure completely so the teeth just glide back.
  Speed: Aim for 40 to 50 strokes per minute. This is much slower than you think. If you go too fast, the teeth will heat up and go dull—even bi-metal blades have their limits.

**Angle and "Lead"**
  Hold the saw at a 45-degree angle to the metal (not perfectly horizontal). This makes the blade cut a wider kerf and prevents it from binding.
  When cutting large pipes or thick bars, rotate the blade slightly so it points diagonally towards he cut. This reduces the surface area the teeth have to cut at once.

**Finishing the Cut**
  As you get to the bottom of the cut, slow down and lighten your pressure. If you push hard at the very end, the metal will tear, leaving a sharp burr, and the saw will jump.
  Hold the piece you are cutting off with your free hand so it doesn't drop and bend the blade as it breaks free.
  YouTube Video on how to use Hacksaw