High-Speed Steel Reamer for Cast Iron Valve Guides (0.404") - Perfect for Automotive Engine Repair and Valve Seat Maintenance

I used this on a cast iron cylinder head to ream out the cooling passage in a 6.5 diesel for a head fix. I would say it was worth it's price. It did exactly what is was made to do and ate the cast iron like it was aluminum. I actually had to use it install the valve guides and found out this was made of very high quality steel when hammering in the value guides. I would say this is about as hard of metal as a transmission gear.