Thread: Milling Cast Iron

No that would be very unwise.

Grey cast iron routs very nicely!

You will need to use a carbide rotary burr cutter. Drill a hole to start from with a bull nosed cutter (these are the best ones for cutting with the end) set at about 2 to 3mm depth for each cut! Im in a bit of a hurry, if I get a minute later I will post a photo!

Agree that it would not be a very wise thing to do.

I have never done so, but a mate of my late brther did so I have no idea what cutter he used but the result was supprisingly good

OK, last post a bit of a rush so here goes!

The photo is of an old enging which I have deck relieved .125".

The cutter was set at this depth and locked down, starting the cut from within the valve pocket or the hole you will have pre drilled in your case.

The cutter used is a carbide, bull nosed, 10mmdia, die grinder burr. These are designed to spin at 22000rpm, which is the same top speed of my makita 1/2" variable speed router. make sure you lock up the depth and don't try to freehand plunge!

For your job you will want to through cut a section out, clamping some type of guide to your table would be best to save any "stuff ups". A 6mm Bull nosed burr would be best for this through cut.

Then you will need to make a final cleanup cut around the edge with a larger 10mm or bigger parallel sided burr.

depending on the insert and thickness of your cast iron wing you may need to rout a rebate (I doubt your wing will be thick enough) for the router insert to sit into, this can be done with a burr with parallel sides and square end.

Buy quality carbide burrs not rubbish!

Be carefull the swarf is sharp and you will need glasses and a faceshield over them, best to wear a cap full coverage clothing and light gloves, but the little sharp burrs will still work their way into the most uncomfortable places!

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