Cutting iron is a common part of small repairs: shortening a pipe, a box section, an angle or a bar for a fence or a shelf. The result depends less on muscle than on preparation: the workpiece must not move, the cutting line must be clear and the blade must not overheat.
Below we explain step by step how to cut iron with a hacksaw or an angle grinder, how to reduce friction and heat, and how to protect the fresh cut from rust, especially if the part will be used outdoors.
What you will need
- a vice or strong clamps
- a hacksaw with a good quality blade or an angle grinder with a cutting disc
- a steel scriber and a triangular file
- a metal file for deburring
- WD-40 Specialist Cutting Oil for cutting
- WD-40 Multi-Use to protect the cut edge
- safety glasses, gloves and ear defenders for the grinder
Important: When using an angle grinder, always wear safety glasses and gloves, hold the tool with both hands and never remove the guard. Sparks travel far, so clear away anything flammable nearby.
Step 1
Clamp the workpiece
Fix the piece in a vice so that the cutting point sits as close to the jaws as possible. Support the free end of a long piece. It must not wobble or vibrate while you cut: this is what gives a straight edge and saves the blade.
To avoid crushing thin box section or pipe, put wooden blocks between the jaws.
Step 2
Choose the cutting tool
For bars, thin pipes and angles a hacksaw is usually enough at home. What matters most is a good blade, with fine teeth for thin metal and coarser teeth for thick stock. For thick metal or a lot of cuts an angle grinder is quicker, and for repeated straight or angled cuts a metal mitre saw is the professional choice.
Step 3
Mark the cutting line
Scribe the line with a steel scriber rather than a marker, as a scratch stays visible through swarf. Then make a small notch on the line with a triangular file. The blade will bite into this groove straight away and will not wander on the first stroke.
Step 4
Cut with lubrication
Hold the saw firmly, use the full length of the blade and press only on the forward stroke. To reduce friction and heat, apply WD-40 Specialist Cutting Oil into the notch through the precision straw and top it up as you go. The blade cuts more easily, runs cooler and lasts longer.
As you near the end of the cut, support the offcut by hand so it does not snap off and leave a torn edge.
Step 5
Deburr and protect the cut
Run a metal file over the cut to remove burrs and sharp edges. The piece should be smooth and safe to handle.
A fresh cut has no coating at all and rusts quickly in damp weather. Wipe it clean and apply a thin film of WD-40 Multi-Use, and if the part is going outdoors, prime and paint it later.
Tip: After the job, blow the swarf out of the vice and spray the screw with
WD-40 Smart Straw: the thin straw reaches deep into the thread, so the vice turns smoothly and does not rust in a damp garage.
What next
Replace hacksaw blades as soon as they start skating instead of cutting, and store them lightly protected. Treat your workshop tools the same way every few months so they are always ready for the next job.
These uses come from the experience of WD-40 users in many countries. Always follow the instructions and warnings on the product label.
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