Working with mild steel.

[Neale]

I've been cutting steel with my router for a while now, on the basis originally of "What could possibly go wrong?" Mainly bright mild (EN1) but more recently EN3B or similar from my local stockholder. The kind of general-purpose mild steel as desctibed by Wal, I suspect.

Key thing for me was finding cutters rated at 8K RPM or more (in the small sizes - 2-4mm - that I normally uae), some kind of coated carbide, usually 3-flute, and also recommended to be used dry, no lubricant or coolant, which is great for someone with a wooden bed machine. The usual 3HP spindle really doesn't have any grunt worth talking about at much under 7K, and I have done more damage to cutters running too slowly and slowing the spindle (you can stall it with a 3mm cutter...) than I have done with cutting faster. I get my cutters from Cutwel.

You need a stiff machine, I suspect. Mine is all welded steel, profile rails, ballscrews. I don't think that rigidity is as big a problem as resonance - if I were building another machine I would go heavier than the 3mm box that I used just for damping.

Not exactly a high-volume production technique but you use what you've got!