Drilling Cast Iron......

[81cutlass]

That's right, cast iron carbon nodules act as graphite so you don't need lubricant.

Otherwise as long as it's not induction hardened it usually cuts easy.

 

[79 GP 4 speed]

I used the grease to stop the shavings from going into the exhaust manifold on my truck. I still had to use a magnet after it was drilled and tapped to make sure all the shavings were out so they didn't go through the turbo.

 

[MC96]

When I turn 5x4.75 to 5x5 for guys I use HSS no lube.

I like cast iron, makes a nice chip

 

[Streetbu]

Drilled out the pushrod holes in my Vortec heads. Grabbed a bit and went at it dry, had both heads done in a minute or two with zero issues.

 

[SSpev]

Used to do a lot of this. 6 foot radial arm any size hole down to 1/8npt. then chuck the tap in. put it on slow and let it eat.☕