Cutting blanks off bar or profile stock (usually 6 or 12 metres long) is one of the most common jobs in a workshop. The classic beginner's mistake is letting the saw blade overheat. An overheated blade dulls quickly, the teeth chip and the cut end of the workpiece ends up burred and discoloured.
Aluminium and steel behave differently when cut, so cooling and feed need a different approach for each. Your main ally here is a dedicated cutting oil that cools the cut and helps the teeth do their work.
What you will need
- WD-40 Specialist Cutting Oil
- WD-40 Multi-Use for cleaning and protection afterwards
- band saw, cut-off saw or hacksaw with a blade of suitable pitch
- vice or clamps
- aluminium or steel bar or profile
- safety glasses, gloves, swarf brush
Important: Wear safety glasses and clamp the workpiece securely. Never clear swarf by hand while the machine is running: use a brush. Ventilate the area if smoke appears.
Step 1
Prepare the workpiece and tool
Mark the length and clamp the bar firmly in the vice so the offcut does not pinch the blade at the end of the cut. Check that the blade is sharp and correctly tensioned: thin-walled profile needs a finer tooth, solid bar a coarser one.
Step 2
Apply the cutting oil
Before you start, spray WD-40 Specialist Cutting Oil onto the cutting edge of the blade and the cut line. The oil carries away heat, keeps both workpiece and tool from overheating and reduces friction so the teeth cut cleanly.
Step 3
Cut the aluminium
Aluminium is soft and cuts easily. One application of oil is usually enough for the whole cut: the blade does not clog, there is no smoke and the end comes out square. Do not press too hard, so the chips can clear the teeth instead of packing the gullets.
Step 4
Cut the steel
Steel is much harder, so work more slowly with steady pressure. Reapply cutting oil several times during the cut and slow down if needed so the teeth actually remove metal rather than rubbing it.
Step 5
Prevent overheating
The first signs of overheating are smoke from the cut, darkening chips and a sharp smell. As soon as you notice them, apply more oil: the smoke dies down almost at once and the temperature drops. Regular cooling multiplies blade life and gives a straight, smooth face even on hard steel.
Step 6
Clean up and protect
Deburr the ends with a file and wipe off swarf and oil residue. Treat steel blanks and the vice with WD-40 Multi-Use: it displaces moisture and protects freshly cut surfaces from rust, especially in an unheated workshop.
Tip: Do not chase speed: on hard steel a slower blade with steady feed and cutting oil gives a cleaner cut and longer blade life than high speed without cooling.
What next
Keep cutting oil next to the saw and apply it at the start of every cut. After work, treat tools and steel stock with WD-40 Multi-Use so they do not rust before 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.
More guides in «How to use».